Sources

Every line here was read against the source linked beneath it. Where the source said something different, the line was corrected. Lines nothing could back are listed as not traced, not hidden, so don’t cite them from Ouranos. Data drawn straight from a catalogue, such as stars and exoplanets, is credited on each card and on the credits page.

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Sun62 traced

Open its page

A ball of hydrogen and helium 109 times Earth's width, fusing 600 million tonnes of hydrogen a second — white in space, its face changing every day.NASA, Five Weird Things That Happen in Outer SpaceNASA NSSDCA, Sun Fact SheetNASA, Sun: FactsStanford Solar Center, What color is the Sun?
diameter · 1,391,400 km · 109 × earthNASA NSSDCA, Sun Fact Sheet; worked out from its numbers
mass · 333,000 earths · 1.988 × 10³⁰ kgNASA NSSDCA, Sun Fact Sheet; worked out from its numbers
surface · 5,772 K · effective temperaturePrsa et al. 2016, IAU 2015 Resolution B3
core · 15.7 million K · modelNASA NSSDCA, Sun Fact Sheet
turns · 25 days at the equator · 35 at the polesNASA SOHO, Lesson: Differential Rotation of the Sun; worked out from its numbers
age · 4.6 billion years · half its lifeNASA, Sun: Facts
light to earth · 8 min 19 sJPL SSD, Astrodynamic Parameters; worked out from its numbers
cycle · ~11 years · sunspot cycle 25NASA/Marshall, The Sunspot CycleNASA, NASA, NOAA: Sun Reaches Maximum Phase in 11-Year Solar Cycle (2024)
width vs earth · 100 · 109×NASA NSSDCA, Sun Fact Sheet
gravity at the surface · 100 · 28×NASA NSSDCA, Sun Fact Sheet
The Sun holds 99.8% of all the mass in the Solar System.NASA, Sun: Facts
It is an ordinary star — a G2 dwarf, one of hundreds of billions in the Milky Way — and it was born about 4.6 billion years ago when a cloud of gas and dust collapsed under its own gravity.NASA, Sun: FactsNASA NSSDCA, Sun Fact SheetCaltech Cool Cosmos, What is the Milky Way?NRAO, How many stars do Andromeda and the Milky Way have?
In its core, at about 15 million degrees, hydrogen nuclei fuse into helium: every second about 600 million tonnes of hydrogen become helium, and around four million tonnes of matter turn into the energy that lights and warms everything in the Solar System.NASA, Five Weird Things That Happen in Outer Space; worked out from its numbersNASA, Sun: FactsNASA NSSDCA, Sun Fact Sheet
That energy takes a long time to get out.NASA, Sun: Facts
In the dense radiative zone the light bounces from particle to particle, a journey NASA puts at about 170,000 years from the core to the top of the convection zone; in the outer third, the convective zone, hot gas rises and cool gas sinks.NASA, Sun: Facts; worked out from its numbersNASA/Marshall, The Solar InteriorNASA/Marshall, Photospheric Features
The tops of those convection cells are the granules that cover the visible surface, the photosphere — each about the size of Texas, lasting about 20 minutes before it is replaced.NASA/Marshall, Photospheric FeaturesNSO, Inouye Solar Telescope first light release
From the photosphere, light reaches Earth in about eight minutes and twenty seconds.JPL SSD, Astrodynamic Parameters; worked out from its numbers
In space the Sun is white: its light peaks in the green but contains every colour, and together they make white.Stanford Solar Center, What color is the Sun?
It looks yellow or orange from the ground because our air scatters away some of its blue, and pictures of it are often coloured: visible-light images may be processed to look orange, and ultraviolet images are given bright colours we can see.Stanford Solar Center, What color is the Sun?NASA SDO, HMI & AIA Channels
Seen in white light its disc is darker and redder towards the edge, where we look through cooler upper layers: limb darkening.Majewski, ASTR 3130 lecture notes, University of VirginiaNASA/Marshall, The Photosphere
The Sun's magnetism drives its weather.NASA, Sun: FactsNASA, Sunspots
Its equator turns in about 25 days and its poles in about 35, winding up magnetic fields that break the surface as dark, cooler sunspots and bright faculae.NASA/Marshall, The Solar DynamoNASA SOHO, Lesson: Differential Rotation of the SunNASA, SunspotsNASA/Marshall, Photospheric Features
Over about 11 years the number of sunspots rises and falls, and the magnetic poles swap places; the current cycle, number 25, reached its maximum around 2024–25.NASA, Sun: FactsNASA/Marshall, The Sunspot CycleNASA, NASA, NOAA: Sun Reaches Maximum Phase in 11-Year Solar Cycle (2024)
Twisted fields can snap in solar flares, and coronal mass ejections hurl billions of tonnes of plasma into space — when they reach Earth they light up the aurorae and can disturb satellites and power grids.NOAA SWPC, Coronal Mass EjectionsNASA/Marshall, Solar FlaresNASA, Sun: Facts
Above the surface lies the corona, an atmosphere of a million degrees or more — far hotter than the surface beneath it, a puzzle still being worked out — which streams outward as the solar wind at 300 to 800 km/s, filling the heliosphere far past Pluto.NASA/Marshall, Solar Wind Features; worked out from its numbersNASA/Marshall, The CoronaNASA/Marshall, The Big QuestionsNASA, Sun: FactsGurnett et al. 2013, Science, In Situ Observations of Interstellar Plasma with Voyager 1NASA NSSDCA, Pluto Fact Sheet
NASA's Parker Solar Probe has flown through the corona itself, passing about 6.1–6.2 million km from the surface in December 2024, the closest any spacecraft has come.Johns Hopkins APL, A Star Explored (2024)NASA, Parker Solar Probe mission page
In about five billion years the Sun will run out of hydrogen in its core, swell into a red giant, and finally shrink to a white dwarf.NASA, Sun: Facts
radius · 695,700 km · iau nominalPrsa et al. 2016, IAU 2015 Resolution B3NASA NSSDCA, Sun Fact Sheet
mean density · 1.41 g/cm³NASA NSSDCA, Sun Fact Sheet; worked out from its numbers
surface gravity · 274 m/s²NASA NSSDCA, Sun Fact Sheet
escape velocity · 617.6 km/sNASA NSSDCA, Sun Fact Sheet
luminosity · 3.828 × 10²⁶ W · iau nominalPrsa et al. 2016, IAU 2015 Resolution B3NASA NSSDCA, Sun Fact Sheet
effective temperature · 5,772 KPrsa et al. 2016, IAU 2015 Resolution B3
spectral type · G2VNASA NSSDCA, Sun Fact Sheet
composition (mass) · hydrogen ~74%, helium ~25% · other elements ~1.3%Asplund et al. 2009, The Chemical Composition of the Sun, ARA&ANASA/Marshall Solar Physics home
round the galaxy · ~200–230 million years · at ~247 km/s, reid et al. 2019NASA, Sun: Facts; worked out from its numbersReid et al. 2019, ApJGRAVITY Collaboration 2022, A&A
from the galactic centre · ~27,000 light-years · 8,277 pc, gravity 2022GRAVITY Collaboration 2022, A&A; worked out from its numbers
rotation (equator) · ~25 days siderealNASA SOHO, Lesson: Differential Rotation of the Sun; worked out from its numbersNASA, Sun: FactsNASA NSSDCA, Sun Fact Sheet
rotation (poles) · ~35 daysNASA SOHO, Lesson: Differential Rotation of the Sun; worked out from its numbers
axis tilt · 7.25° · to the eclipticNASA NSSDCA, Sun Fact SheetNASA, Sun: Facts
photosphere · ~5,800 K · the visible surfaceRyden, Astronomy 162 Lecture 4, Ohio State UniversityNASA/Marshall, The Photosphere
chromosphere · to ~2,000 km up · pink in an eclipseNOAA NCEI, chromosphere imagery data description: Ca II K shows it from about 500 to 2,000 km above the photosphereRyden, Astronomy 162 Lecture 4, Ohio State University
corona · 1–3 million K · seen in an eclipse or in ultravioletImamura, The Sun: A Typical Star, University of OregonNASA, Sun: FactsNASA SDO, HMI & AIA ChannelsNASA/Marshall, The Corona
solar wind · 300–800 km/s · about a million tonnes a secondHyperPhysics, The Solar WindRyden, Astronomy 162 Lecture 4, Ohio State UniversityNASA/Marshall, Solar Wind Features
core · to ~25% of the radius · fusion, ~15.7 million KNASA/Marshall, The Solar InteriorNASA NSSDCA, Sun Fact Sheet
radiative zone · to ~70% · helioseismologyNASA/Marshall, The Solar InteriorNASA/Marshall, Helioseismology
convective zone · outer ~30% · helioseismologyNASA/Marshall, The Solar Interior; worked out from its numbersNASA/Marshall, Helioseismology
granules · ~1,000 km · minutes eachNASA/Marshall, Photospheric Features
Sound waves ringing through the Sun — helioseismology, measured by SOHO and SDO — map its interior; you can hear them sped up on the listen channel.Stanford Solar Center, sounds of the SunNASA/Marshall, HelioseismologyNASA SDO, HMI & AIA Channels
sunspot fields · ~0.1–0.4 tesla · thousands of times earth'sSolanki, Inhester & Schussler 2006, Rep. Prog. Phys. 69, 563; worked out from its numbersNASA NSSDCA, Sun Fact SheetNASA/Marshall, Photospheric Features
magnetic cycle · ~22 years · two sunspot cyclesNASA/Marshall, The Solar DynamoPetrovay & Christensen 2010, The Magnetic Sun
heliosphere · to ~120 au · voyager 1 crossed in 2012Gurnett et al. 2013, Science, In Situ Observations of Interstellar Plasma with Voyager 1NASA, Voyager 1 mission page
1990–2009 · ulysses · over the polesNASA, Ulysses mission page
1995– · soho · esa/nasa, at l1NASA, SOHO mission page
2010– · sdo · the face you see hereNASA SDO, Mission
2018– · parker solar probe · through the coronaNASA NSSDCA catalog, Parker Solar ProbeNASA, Parker Solar Probe mission page
2020– · solar orbiter · esa, first polar imagesNASA, Solar Orbiter mission pageESA, Solar Orbiter gets world-first views of the Sun's poles
2023– · aditya-l1 · india, at l1ESA, How is ESA supporting ISRO's Aditya-L1 solar mission?
brightness · mag −26.74NASA NSSDCA, Sun Fact Sheet
apparent size · 31.45′ – 32.53′NASA NSSDCA, Sun Fact Sheet; worked out from its numbers
never look at it · without a proper solar filterNASA, Eclipse Viewing Safety

Mercury59 traced

Open its page

The smallest planet and the closest to the Sun — a dense iron world under a cratered crust, scorched by day and frozen by night.NASA Science, Mercury FactsMESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011
diameter · 4,879 km · 0.38 × earthNASA NSSDCA, Planetary Fact SheetNASA NSSDCA, Mercury Fact Sheet
mass · 0.055 earths · 3.30 × 10²³ kgNASA NSSDCA, Mercury Fact Sheet
solar day · 176 days · two of its yearsNASA Science, Mercury Facts; worked out from its numbersHorner et al. 2020, Solar System Physics for Exoplanet Research
year · 88.0 daysNASA NSSDCA, Planetary Fact Sheet
from the sun · 57.9 M km · 0.39 auNASA NSSDCA, Mercury Fact SheetNASA NSSDCA, Planetary Fact Sheet
surface · −180 to 430 °C · night to dayNASA Science, Mercury Facts
moons · 0NASA NSSDCA, Mercury Fact SheetNASA Science, Mercury Facts
core · ~83% of its radius · modelHauck et al. 2013, JGR Planets, The curious case of Mercury's internal structure; worked out from its numbersNASA Science, Mercury Facts
width vs earth · 38 · 0.38×NASA NSSDCA, Mercury Fact Sheet
gravity vs earth · 38 · 0.38×NASA NSSDCA, Mercury Fact Sheet
sunlight received · 100 · 6.7× earth'sNASA NSSDCA, Mercury Fact Sheet
Mercury is the smallest of the eight planets, only a little larger than our Moon, and the one closest to the Sun.NASA Science, Mercury Facts
From its surface the Sun looks two to three times as wide as it does from Earth and pours down almost seven times as much light on average.NASA Science, Mercury Facts; worked out from its numbersNASA NSSDCA, Mercury Fact Sheet
Yet it is not the hottest planet — Venus is — because Mercury has almost no air to hold heat: its days reach about 430 °C and its nights fall to about −180 °C, the widest swing of any planet.NASA Science, Mercury FactsMESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011
It turns slowly and in step with its orbit: three rotations for every two trips round the Sun.Margot et al. 2018, Mercury's Internal Structure
The result is a day — sunrise to sunrise — that lasts 176 Earth days, two of Mercury's years.NASA Science, Mercury FactsHorner et al. 2020, Solar System Physics for Exoplanet Research
At some places on its surface the Sun rises, stops, goes briefly backwards and rises again, because near perihelion its orbital speed outruns its spin.NASA Science, Mercury FactsHorner et al. 2020, Solar System Physics for Exoplanet Research
For its size Mercury is astonishingly dense.Margot et al. 2018, Mercury's Internal StructureHorner et al. 2020, Solar System Physics for Exoplanet Research
An iron core takes up about 83–85% of its radius, leaving a thin rocky mantle and crust — as if most of an ordinary planet's rock had been stripped away, perhaps by a giant impact early on or by the young Sun's heat.Hauck et al. 2013, JGR Planets, The curious case of Mercury's internal structure; worked out from its numbersNASA Science, Mercury FactsMESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011Ebel & Stewart 2018, The Elusive Origin of Mercury
Some of that core is still molten, and it drives a weak magnetic field, about one percent of Earth's, discovered by Mariner 10 in 1974.NASA Science, Mercury FactsMESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011NASA 2019, A Closer Look at Mercury's Spin and GravitySun et al. 2021, Review of Mercury's Dynamic Magnetosphere, Science China Earth Sciences
Its face records a violent past.NASA Science, Mercury Facts
The Caloris Basin, about 1,550 km across, was blasted out by an impact long thought to have sent shock waves through the whole planet and jumbled the ground on the far side, an idea a 2020 study of MESSENGER's images disputes.NASA Science, Mercury FactsRodriguez et al. 2020, Scientific Reports, The Chaotic Terrains of Mercury
Long cliffs called lobate scarps, some over a kilometre high and hundreds of kilometres long, formed as the planet cooled and shrank.MESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011NASA Science, Mercury Facts
MESSENGER found bright 'hollows' where something in the rock seems to have been vaporising away, perhaps still today, and evidence of water ice hiding in the permanent shadow of craters near the poles — ice on the planet nearest the Sun.Blewett et al. 2011, Science 333, 1856NASA Science, Mercury's Strange HollowsNASA Science, MESSENGER mission page
Only two spacecraft had been before BepiColombo: Mariner 10 flew past three times in 1974–75, and MESSENGER orbited from 2011 until it was crashed into the surface in 2015, mapping the whole planet.NASA Science, MESSENGER mission pageNASA NSSDCA, Mariner 10 catalog entryNASA Science, Exploration of MercuryMESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011
The European–Japanese BepiColombo, launched in 2018, flew past six times on its way to an orbit planned for November 2026.ESA, BepiColombo factsheetESA, Latest updates: BepiColombo's arrival at Mercury
mean radius · 2,439.7 kmNASA NSSDCA, Mercury Fact Sheet
mean density · 5.429 g/cm³ · earth 5.51NASA NSSDCA, Mercury Fact SheetNASA NSSDCA, Planetary Fact Sheet
surface gravity · 3.70 m/s²NASA NSSDCA, Mercury Fact Sheet
escape velocity · 4.3 km/sNASA NSSDCA, Mercury Fact Sheet
bond albedo · 0.068NASA NSSDCA, Mercury Fact Sheet
geometric albedo · 0.142NASA NSSDCA, Mercury Fact Sheet
caloris basin · ~1,550 km acrossNASA Science, Mercury Facts
semi-major axis · 57.91 M km · 0.387 auNASA NSSDCA, Mercury Fact Sheet
perihelion · aphelion · 46.0 · 69.8 M kmNASA NSSDCA, Mercury Fact SheetNASA NSSDCA, Planetary Fact Sheet
eccentricity · 0.2056 · the most of any planetNASA NSSDCA, Mercury Fact SheetNASA NSSDCA, Planetary Fact Sheet
inclination · 7.00°NASA NSSDCA, Mercury Fact Sheet
sidereal period · 87.97 daysNASA NSSDCA, Mercury Fact Sheet
rotation · 58.646 days · 3 turns per 2 orbitsJPL SSD, Planetary Physical Parameters; worked out from its numbersMargot et al. 2018, Mercury's Internal Structure
axial tilt · 0.034° · no seasonsNASA NSSDCA, Mercury Fact Sheet; worked out from its numbersNASA Science, Mercury FactsNoyelles & Lhotka 2013, Advances in Space Research (arXiv:1211.7027): Mercury's measured obliquity "(2.04 +/- 0.08) arcmin"
air · an exosphere only · surface pressure < ~5 × 10⁻¹⁵ barNASA NSSDCA, Mercury Fact Sheet
atoms found · oxygen, sodium, hydrogen, helium, potassiumNASA Science, Mercury Facts
sodium tail · streams anti-sunward · pushed by sunlightNASA NTRS 20150010997, Observation of neutral sodium above Mercury during the transitNASA image article, Mercury's Sodium Tail
core radius · ~2,020–2,074 km · hauck et al. 2013; nasaHauck et al. 2013, JGR Planets, The curious case of Mercury's internal structureNASA Science, Mercury Facts
solid inner core · ~600–1,400 km radius · genova et al. 2019, modelGenova et al. 2019, GRL, Geodetic Evidence That Mercury Has A Solid Inner Core; worked out from its numbersNASA 2019, A Closer Look at Mercury's Spin and Gravity
mantle + crust · ~400 km thick · modelMargot et al. 2018, Mercury's Internal StructureNASA Science, Mercury Facts
MESSENGER's gravity and spin measurements point to a large core with a solid inner part — a structure much like Earth's, but with far less rock around it.Genova et al. 2019, GRL, Geodetic Evidence That Mercury Has A Solid Inner CoreNASA 2019, A Closer Look at Mercury's Spin and GravityMargot et al. 2018, Mercury's Internal Structure
field at the surface · 250–700 nT · about 1% of earth'sNASA NSSDCA, Mercury Fact Sheet; worked out from its numbersNASA Science, Mercury Facts
dipole · offset ~480 km north · anderson et al. 2011Anderson et al. 2011, Science 333, 1859Sun et al. 2021, Review of Mercury's Dynamic Magnetosphere, Science China Earth Sciences
discovered · mariner 10, 1974Sun et al. 2021, Review of Mercury's Dynamic Magnetosphere, Science China Earth SciencesNASA NSSDCA, Mariner 10 catalog entry
moons · noneNASA Science, Mercury FactsNASA NSSDCA, Mercury Fact Sheet
1974–75 · mariner 10 · three flybys, 45% mappedNASA NSSDCA, Mariner 10 catalog entryMESSENGER Mercury Orbit Insertion press kit, NASA/JHU APL, 2011
2008–09 · messenger · three flybysNASA Science, MESSENGER mission page
2011–15 · messenger · orbiter, whole planet mappedNASA Science, MESSENGER mission page
2018– · bepicolombo · esa/jaxa, orbit planned for nov 2026ESA, BepiColombo factsheetESA, Latest updates: BepiColombo's arrival at Mercury
brightest · mag −2.4NASA NSSDCA, Mercury Fact Sheet
from the sun · never more than 28° · low at dusk or dawnUniversity of Rochester, AST 104, The Planet MercuryNASA Science, Exploration of Mercury
apparent size · 4.5″ – 13″NASA NSSDCA, Mercury Fact Sheet

Venus61 traced

Open its page

Earth's near-twin in size, wrapped in a crushing carbon-dioxide atmosphere and clouds of sulfuric acid — the hottest surface of any planet.NASA Venus factsNASA NSSDCA Venus fact sheetTitov et al. 2018, Space Sci Rev 214, 126
diameter · 12,104 km · 0.95 × earthNASA NSSDCA Venus fact sheet; worked out from its numbersNASA NSSDCA planetary fact sheet, ratio to EarthNASA Venus facts
mass · 0.815 earths · 4.87 × 10²⁴ kgNASA NSSDCA Venus fact sheetNASA NSSDCA planetary fact sheet, ratio to Earth
day (sidereal) · 243.0 days · backwardsNASA NSSDCA Venus fact sheet; worked out from its numbersJPL SSD planetary physical parameters
year · 224.7 daysNASA NSSDCA Venus fact sheet
from the sun · 108.2 M km · 0.72 auNASA NSSDCA Venus fact sheetJPL SSD approximate planetary elements, Table 1
surface · 464 °C · day and nightNASA NSSDCA Venus fact sheet
pressure · 92 bar · ~900 m under the seaNASA NSSDCA Venus fact sheetNASA Venus factsSolar System Physics for Exoplanet Research, arXiv:2004.13209
moons · 0NASA NSSDCA Venus fact sheetNASA Venus facts
width vs earth · 95 · 0.95×NASA NSSDCA planetary fact sheet, ratio to Earth
gravity vs earth · 90 · 0.90×NASA NSSDCA Venus fact sheet; worked out from its numbersNASA NSSDCA planetary fact sheet, ratio to Earth
air pressure · 100 · 92×NASA NSSDCA planetary fact sheet, ratio to Earth
Venus is almost Earth's twin in size and mass, and it comes closer to us than any other planet.NASA Venus factsJPL, Venus: a planetary portrait of inner beautyNASA Venus lithograph
But where Earth kept oceans, Venus ended up with an atmosphere of carbon dioxide so thick that the pressure at the surface is 92 times ours — like being nearly a kilometre under the sea — and a runaway greenhouse effect holds the ground at about 464 °C, hot enough to melt lead, by day and by night alike.NASA NSSDCA Venus fact sheetNASA NSSDCA planetary fact sheet, ratio to EarthNASA Venus facts
Its clouds, made of droplets of sulfuric acid, cover the whole planet in a layer between about 48 and 70 km up, and reflect most of the sunlight that reaches them.Titov et al. 2018, Space Sci Rev 214, 126
That is why Venus shines so brightly in our sky, brighter than anything but the Sun and the Moon — and why reflected sunlight never shows a telescope its surface.NASA Venus factsNASA Venus lithographTitov et al. 2018, Space Sci Rev 214, 126
Visible light first saw it from space as the heat glow of the ground on the night side, caught by Parker Solar Probe's WISPR camera (Wood et al. 2022).Wood et al. 2022, GRL (abstract, via Europe PMC)NASA, Parker Solar Probe first visible-light images of the surfaceNASA SVS, New Views of Venus' Surface From Space
The cloud tops race round the planet in about four days, 60 to 80 times faster than the ground beneath turns: a 'superrotation' still not fully explained.Brightness modulations of Venus, Nature Communications 2020ESA Venus Express, super-rotation is speeding upNASA Venus lithographEGU25-5337 abstractMarkiewicz et al., EGU2008-A-03630
The planet itself turns very slowly and backwards: one rotation takes 243 Earth days, longer than its year, and the Sun rises in the west.NASA Venus factsNASA NSSDCA Venus fact sheetNASA Venus lithograph
Radar from the Magellan orbiter (1990–94) mapped the hidden surface — vast volcanic plains, thousands of volcanoes, and strange formations such as 'pancake' domes and ringed 'coronae' that appear unique to Venus.NASA Magellan mission pageNASA Venus factsESA, Venus and Earth comparedSan Diego State University, How Volcanoes Work: Venus
Few craters means the surface is young, possibly repaved by volcanism: NASA says its average age could be as young as 150 million years, with older surfaces mixed in, and other estimates run to 300–600 million.NASA Venus factsBottke et al. 2026, arXiv:2606.05036, sec. 7.3NASA Venus lithograph
How volcanically active Venus is today remains one of its biggest unknowns.Assessing the evidence for active volcanism on Venus, review, NASA NTRSHerrick & Hensley 2023, Science (abstract, via Europe PMC)
In 2023 scientists comparing Magellan radar images taken months apart found a volcanic vent near Maat Mons that had changed shape and grown — the first direct geological evidence of recent volcanic activity on Venus.JPL, NASA's Magellan data reveals volcanic activity on VenusHerrick & Hensley 2023, Science (abstract, via Europe PMC)Assessing the evidence for active volcanism on Venus, review, NASA NTRS
The Soviet Venera landers were the only craft to reach the surface and send back pictures; Venera 13 in 1982 survived 127 minutes and returned the first colour images before the heat and pressure overcame it.NASA SVS, New Views of Venus' Surface From SpaceSiddiqi, Beyond Earth, NASA history bookNASA APOD 1999 Jan 24, A Venus LandingNASA Venus lithograph
Orbiters have studied it since — Venus Express (2006–14) and Japan's Akatsuki (observing from 2015, silent from 2024, mission ended 2025), whose ultraviolet images of the cloud tops this globe wears.Titov et al. 2018, Space Sci Rev 214, 126ESA Venus ExpressNASA Venus Express pageNASA Akatsuki pageThe Planetary Society, AkatsukiYamazaki et al. 2018, Earth Planets Space 70, 23: Akatsuki's UV imagesNASA PDS, Akatsuki UVI instrument description
New missions — NASA's DAVINCI and VERITAS and ESA's EnVision — are planned for the 2030s.NASA VERITAS overviewThe Planetary Society, DAVINCIESA EnVisionNASA Venus overview
mean radius · 6,051.8 kmNASA NSSDCA Venus fact sheetJPL SSD planetary physical parameters
mean density · 5.243 g/cm³JPL SSD planetary physical parametersNASA NSSDCA Venus fact sheet
surface gravity · 8.87 m/s²NASA NSSDCA Venus fact sheetJPL SSD planetary physical parameters
escape velocity · 10.36 km/sNASA NSSDCA Venus fact sheetJPL SSD planetary physical parameters
bond albedo · 0.77 · jupiter's is 0.343NASA NSSDCA Venus fact sheet; worked out from its numbers
geometric albedo · 0.689NASA NSSDCA Venus fact sheet
semi-major axis · 108.21 M km · 0.723 auNASA NSSDCA Venus fact sheetJPL SSD approximate planetary elements, Table 1
eccentricity · 0.0068 · the most circularNASA NSSDCA Venus fact sheetPogge, Ohio State Astronomy 161, Venus UnveiledNASA NSSDCA planetary fact sheet
inclination · 3.39°JPL SSD approximate planetary elements, Table 1NASA NSSDCA Venus fact sheet
sidereal period · 224.70 daysNASA NSSDCA Venus fact sheet
rotation · 243.02 days, retrogradeJPL SSD planetary physical parametersNASA NSSDCA Venus fact sheet
solar day · 116.75 daysNASA NSSDCA Venus fact sheet; worked out from its numbersNASA Venus lithograph
axial tilt · 177.4° · upside downNASA NSSDCA Venus fact sheetPogge, Ohio State Astronomy 161, Venus Unveiled
carbon dioxide · 96.5NASA NSSDCA Venus fact sheet
nitrogen · 3.5NASA NSSDCA Venus fact sheet
surface pressure · 92 barNASA NSSDCA Venus fact sheet
surface temperature · 464 °C · 737 KNASA NSSDCA Venus fact sheet
clouds · sulfuric acid droplets · ~48–70 km upTitov et al. 2018, Space Sci Rev 214, 126NASA Venus facts
cloud-top winds · ~100 m/s · round the planet in ~4 daysESA Venus Express, super-rotation is speeding up; worked out from its numbersNASA Venus factsNASA Venus lithograph
iron core radius · ~2,900–4,350 km · modelShah et al. 2021, Interior Structure Models of Venus, arXiv:2112.03225
crust · ~8–25 km · james et al. 2013, modelJames, Zuber & Phillips 2013, JGR Planets (abstract, MIT DSpace)
No seismometer has given a clear reading of Venus. Venera 13 and 14 carried simple geophones: 13 recorded nothing, and 14 may have recorded two small signals in about an hour. So its interior is inferred from its size, density and gravity field.Lorenz & Panning 2017, arXiv:1704.05924Shah et al. 2021, Interior Structure Models of Venus, arXiv:2112.03225
internal field · none detectedNASA Venus factsNASA NSSDCA planetary fact sheet
induced magnetosphere · from the solar wind meeting the ionosphereNASA Venus facts
moons · noneNASA Venus factsNASA NSSDCA Venus fact sheet
1962 · mariner 2 · first successful planetary flybyNASA Mariner 2 pageNASA Venus lithograph
1970 · venera 7 · first signal from another planet's surfaceSiddiqi, Beyond Earth, NASA history bookNASA Venus lithograph
1975 · venera 9 · first pictures from the surfaceSiddiqi, Beyond Earth, NASA history book
1982 · venera 13 · colour pictures, 127 minutesSiddiqi, Beyond Earth, NASA history bookNASA APOD 1999 Jan 24, A Venus Landing
1990–94 · magellan · radar map of 98%NASA Magellan mission pageNASA Venus lithograph
2006–14 · venus express · esa orbiterESA Venus ExpressNASA Venus Express page
2015–25 · akatsuki · jaxa orbiter, silent from 2024NASA Akatsuki pageThe Planetary Society, Akatsuki
brightest · mag −4.8 · the brightest planetNASA NSSDCA Venus fact sheetNASA Venus lithograph
apparent size · 9.7″ – 66.1″NASA NSSDCA Venus fact sheet
phases · like the moon's · seen by galileo, 1610NASA Earth Observatory, Planetary MotionNASA, Galileo's Phases of Venus and Other Planets

Earth60 traced

Open its page

Home: the only world known to have life — liquid oceans, a breathable atmosphere and a magnetic shield.NASA, Facts About EarthNASA, Earth's Magnetosphere
diameter · 12,756 km · at the equatorNASA, Facts About Earth
mass · 5.972 × 10²⁴ kgNASA NSSDCA Earth Fact SheetJPL SSD, Planetary Physical Parameters
day · 23 h 56 m 4 s · siderealESA, Geostationary orbitNASA NSSDCA Earth Fact Sheet
year · 365.256 daysNASA NSSDCA Earth Fact Sheet
from the sun · 149.6 M km · 1 auNASA NSSDCA Earth Fact SheetJPL SSD, Planetary Physical Parameters
mean surface · 15 °CNASA NSSDCA Earth Fact Sheet
moons · 1 · the moonNASA NSSDCA Earth Fact SheetNASA, Facts About Earth
ocean · ~71% of the surfaceNASA, Facts About Earth
Earth is the largest of the four rocky planets and the only world known to have life.NASA, Facts About Earth
About 71% of its surface is ocean — liquid water, which it can keep because it lies at the right distance from the Sun and has an atmosphere that holds in heat.NASA, Facts About EarthNASA, What is the habitable zone?NASA, Evidence (climate change)
That atmosphere, 78% nitrogen and 21% oxygen, owes its oxygen to life itself: photosynthesis by ocean microbes and plants filled the air over billions of years.NASA, Facts About EarthNASA, Basics of Space Flight, ch. 1NOAA, How much oxygen comes from the ocean?Lyons et al. 2014, Nature
It is also the only planet known to have plate tectonics.NASA, Basics of Space Flight, ch. 1
Its rigid outer shell is broken into plates that drift a few centimetres a year, building mountains, opening oceans and recycling crust into the mantle.USGS, The Interior of the EarthUSGS, This Dynamic Earth: Understanding plate motions
That cycle helps keep the climate stable over long times by drawing carbon dioxide out of the air and returning it through volcanoes.NASA Earth Observatory, The Carbon Cycle
Deep inside, a solid iron-nickel inner core about 1,220 km in radius sits inside a liquid outer core whose churning generates the magnetic field.NASA, Facts About EarthNASA, Earth's MagnetosphereUSGS, The Interior of the EarthEARTH Magazine, March 29, 1936: Lehmann notes Earth's inner core
The field forms a magnetosphere that deflects most of the solar wind, protects the atmosphere, and channels particles into the poles to light the aurorae — the green curtains astronauts photograph from the International Space Station.NASA, Earth's MagnetosphereNASA, Facts About EarthNASA Earth Observatory, Cruising Past the Aurora Borealis
Earth's axis is tilted 23.4°, which gives it its seasons, and its large Moon holds that tilt in a narrow range, about 22° to 24.5°.NASA, Facts About EarthLissauer et al., Rotation of a Moonless Earth (NASA NTRS)
Seen from space it is mostly blue and white: oceans and clouds, with deserts, forests and ice between.NASA Earth Observatory, History of the Blue MarbleNASA Earth Observatory, Blue Marble: Next Generation
From Saturn, Cassini photographed it as a blue dot far beyond the rings.NASA Photojournal PIA17171NASA Photojournal PIA14949NASA, The Day the Earth Smiled
Its own climate is changing quickly.NASA, Evidence (climate change)
Carbon dioxide in the air, about 280 parts per million before the industrial age, passed 420 ppm in the 2020s — measured continuously at Mauna Loa since 1958 — and the planet's average temperature has risen by more than 1 °C.NOAA Climate.gov, Atmospheric Carbon DioxideNOAA GML, Mauna Loa annual mean CO2NOAA Climate.gov, Global Temperature
Satellites track sea ice daily, sea level every ten days and the weather almost continuously.NSIDC, Sea Ice IndexNASA Earthdata, Sentinel-6BNOAA NESDIS, Geostationary Satellites
equatorial radius · 6,378.1 kmNASA NSSDCA Earth Fact SheetJPL SSD, Planetary Physical Parameters
polar radius · 6,356.8 kmNASA NSSDCA Earth Fact Sheet
mean density · 5.513 g/cm³ · the densest planetNASA NSSDCA Earth Fact SheetJPL SSD, Planetary Physical ParametersNASA, Facts About Mercury
surface gravity · 9.81 m/s²NASA NSSDCA Earth Fact SheetJPL SSD, Planetary Physical Parameters
escape velocity · 11.19 km/sJPL SSD, Planetary Physical ParametersNASA NSSDCA Earth Fact Sheet
bond albedo · 0.294NASA NSSDCA Earth Fact Sheet
highest · deepest · 8,849 m · −10,935 m · everest · challenger deepNOAA Ocean Exploration, National Ocean MonthNOAA, How deep is the ocean?
semi-major axis · 149.60 M km · 1.000 auNASA NSSDCA Earth Fact Sheet
perihelion · aphelion · 147.1 · 152.1 M km · january · julyNASA NSSDCA Earth Fact SheetNASA Space Place, What causes the seasons?
eccentricity · 0.0167NASA NSSDCA Earth Fact Sheet
sidereal period · 365.256 daysNASA NSSDCA Earth Fact Sheet
rotation · 23 h 56 m 4.1 sJPL SSD, Planetary Physical Parameters; worked out from its numbersNASA NSSDCA Earth Fact Sheet
axial tilt · 23.44° · the seasonsNASA NSSDCA Earth Fact SheetNASA, Facts About Earth
geostationary ring · 35,786 km up · one turn a day, over one spot on the equatorESA, Geostationary orbit
graveyard orbit · ~300 km higher · where old satellites are retiredESA, Graveyard orbit 300 km above GEO
nitrogen · 78.08NASA NSSDCA Earth Fact Sheet
oxygen · 20.95NASA NSSDCA Earth Fact Sheet
argon · 0.93NASA NSSDCA Earth Fact Sheet; worked out from its numbers
other · 0.04NASA NSSDCA Earth Fact Sheet; worked out from its numbers
carbon dioxide · ~425 ppm · mauna loa, 2024NOAA Climate.gov, Atmospheric Carbon DioxideNOAA GML, Mauna Loa annual mean CO2
surface pressure · 1.013 barNOAA JetStream, Air pressureNASA NSSDCA Earth Fact Sheet
water vapour · ~0–4% · variesNOAA JetStream, The atmosphereUCAR, What's in the air?
inner core · ~1,220 km radius, solid iron and nickel · seismologyNASA, Facts About EarthUSGS, The Interior of the EarthEARTH Magazine, March 29, 1936: Lehmann notes Earth's inner core
outer core · to ~3,480 km radius, liquid · seismologyNASA NSSDCA Earth Fact Sheet; worked out from its numbersUSGS, The Interior of the EarthNASA, Earth's Magnetosphere
mantle · ~2,900 km thick · seismologyNASA, Facts About EarthUSGS, The Interior of the Earth
crust · ~5–70+ kmNASA, Facts About EarthUSGS, The Interior of the EarthMooney, Prodehl & Pavlenkova, USGS
centre · ~5,400 °C or more, ~3.6 million bar · estimates varyNASA, Facts About Earth; worked out from its numbersMorard et al. 2011, The melting curve of iron at extreme pressures, arXiv:1010.5133 (High Energy Dens.Phys.7:141-144,2011)Low viscosity of the Earth's inner core, Nature Communications 2019
field at the surface · 25,000–65,000 nT · 0.25–0.65 gaussNOAA NCEI, Geomagnetism FAQNASA NSSDCA Earth Fact Sheet
dipole tilt · ~9.2° to the spin axis · igrf-14, 2025IGRF-14 coefficients, NOAA NGDC; worked out from its numbersNOAA NCEI, Wandering of the Geomagnetic Poles
reach toward the sun · ~10 earth radii · ~64,000 kmScolini et al., arXiv:1712.05847; worked out from its numbersNASA, Magnetosphere and ionosphere
the moon · 3,474.8 km across · 384,400 km awayNASA NSSDCA Moon Fact Sheet; worked out from its numbersNASA, Facts About Earth
1957 · sputnik 1 · first satelliteNASA, Sputnik and the Dawn of the Space Age
1961 · vostok 1 · first human in orbitNASA, Yuri Gagarin: First Human in Space
1968 · apollo 8 · 'earthrise'NASA SVS, Earthrise in 4KNASA, Apollo 8: Earthrise
1972 · apollo 17 · 'the blue marble'NASA Earth Observatory, History of the Blue MarbleNASA, Blue Marble from Apollo 17
1998– · iss · people aboard since 2000NASA, International Space Station; worked out from its numbersNASA, Space Station overview
from the moon · mag ~−17 at full · ~3.7× the moon's widthNASA NTRS, NASA's Planned Return to the Moon: Global Access; worked out from its numbersNASA NSSDCA Earth Fact SheetNASA NSSDCA Moon Fact Sheet

Moon55 traced

Open its page

A quarter of Earth's width, locked face-on to us, its dark seas of old lava and bright cratered highlands mapped down to a metre.NASA NSSDCA, Moon Fact Sheet; worked out from its numbersNASA Science, Tidal LockingNASA Science, Moon CompositionNASA NSSDCA Master Catalog, LRO
diameter · 3,474.8 km · 0.27 × earthNASA NSSDCA, Moon Fact Sheet; worked out from its numbers
mass · 0.0123 earths · 7.35 × 10²² kgNASA NSSDCA, Moon Fact Sheet; worked out from its numbers
month · 29.53 days · new to newEspenak, NASA GSFC, Eclipses and the Moon's OrbitNASA Science, Moon Phases
turns · 27.32 days · face-on to earthNASA NSSDCA, Moon Fact Sheet; worked out from its numbersNASA Science, Tidal Locking
from earth · 384,400 km · meanNASA NSSDCA, Moon Fact Sheet
surface · −173 to 127 °C · full sun to darknessNASA Science, Moon Facts; worked out from its numbersNASA NSSDCA, Moon Fact Sheet
walked on · 12 people · 1969–72NASA Science, Moon Exploration
drifting away · 3.8 cm / year · laser rangingNASA NSSDCA, Moon Fact SheetNASA JPL, Apollo 11 Experiment Continues to Return Valuable Data
width vs earth · 27 · 0.27×NASA NSSDCA, Moon Fact Sheet
gravity vs earth · 17 · 0.17×NASA NSSDCA, Moon Fact Sheet
The Moon is Earth's only natural satellite and the fifth-largest moon in the Solar System.NASA Science, Moon FactsNASA APOD 2025 August 23
It was most likely born from a giant collision about 4.5 billion years ago, when a Mars-sized body struck the young Earth and threw out debris that gathered into a ball — the reason Moon rock is so like Earth's mantle, and the Moon so poor in iron.NASA Science, How the Moon Formed
It turns once on its axis in exactly the time it takes to orbit, so the same face always points at us; tides raised by Earth locked it that way long ago.NASA Science, Tidal Locking
Those tides work in both directions: the Moon raises our ocean tides, slows Earth's spin, and is drifting away by about 3.8 cm a year — measured by firing lasers at reflectors left by Apollo astronauts.NASA Science, TidesNASA JPL, The Apollo Experiment That Keeps on GivingNASA JPL, Apollo 11 Experiment Continues to Return Valuable DataNASA NSSDCA, Moon Fact Sheet
Its face is a record of the early Solar System.NASA Science, Moon Facts
The bright highlands are ancient crust, pounded by impacts.NASA Science, Moon Composition
The dark 'seas' (maria) are lava that flooded the largest basins between about 4.2 and 1.2 billion years ago.NASA Science, Moon CompositionNASA Science, Moon Facts
With almost no air and no weather, footprints and craters last for millions of years; the largest basin, South Pole–Aitken on the far side, is about 2,500 km across.NASA NSSDCA, 30th Anniversary of Apollo 11NASA Science, Moon FactsNASA Photojournal PIA13496, The Moon's Largest Impact BasinNASA SVS 3582, Lunar Topography in False Color
Twelve people walked on the Moon between July 1969 and December 1972, on six Apollo missions, and brought back 382 kg of rock and soil.NASA Science, Moon ExplorationNASA NSSDCA, The Apollo ProgramNASA NSSDCA, Lunar Exploration TimelineNASA Science, Moon Facts
Robotic missions returned after a gap from 1976 to 1990: NASA's Lunar Reconnaissance Orbiter has mapped it at under a metre a pixel since 2009 — its photographs of the landing sites, with the astronauts' tracks and rovers still visible, are in Ouranos — and China's Chang'e 4 made the first landing on the far side in 2019.NASA NSSDCA, Lunar Exploration TimelineNASA Science, LRO AboutNASA History, 15 Years Ago: LRO Begins Moon Mapping MissionNASA NSSDCA Master Catalog, LROC experimentNASA Science, 10 Cool Things LRO Is Teaching UsNASA Science, Moon Missions
The poles now draw close attention.NASA, NASA Identifies Candidate Regions for Landing Next Americans on Moon
Some craters there never see sunlight and are among the coldest places measured in the Solar System; water ice is trapped in some of those shadows.NASA SVS 4043, LRO Peers into Permanent ShadowsNASA Science, 10 Cool Things LRO Is Teaching UsNASA Science, Moon Water and Ices
India's Chandrayaan-3 landed near the south pole in 2023, China's Chang'e 6 brought back the first far-side samples in 2024, and NASA's Artemis programme aims to land people in the south polar region.NASA Science, Moon MissionsNASA, LRO Observes Chandrayaan-3 Landing SiteThe Planetary Society, Chang'e-6NASA, NASA Identifies Candidate Regions for Landing Next Americans on Moon
mean radius · 1,737.4 kmNASA NSSDCA, Moon Fact Sheet
mean density · 3.344 g/cm³NASA NSSDCA, Moon Fact Sheet; worked out from its numbers
surface gravity · 1.62 m/s² · one-sixth of earth'sNASA NSSDCA, Moon Fact Sheet; worked out from its numbers
escape velocity · 2.38 km/sNASA NSSDCA, Moon Fact Sheet
geometric albedo · 0.12 · as dark as worn asphaltNASA NSSDCA, Moon Fact SheetC. Baird, West Texas A&M University, Why is the moon so bright?
south pole–aitken · ~2,500 km across · the largest basinNASA Photojournal PIA13496, The Moon's Largest Impact Basin
mean distance · 384,400 kmNASA NSSDCA, Moon Fact Sheet
perigee · apogee · 363,300 · 405,500 kmNASA NSSDCA, Moon Fact Sheet
eccentricity · 0.0549NASA NSSDCA, Moon Fact Sheet
inclination · 5.145° · to the eclipticNASA NSSDCA, Moon Fact Sheet
sidereal month · 27.322 daysNASA NSSDCA, Moon Fact SheetNASA Science, Moon Phases
synodic month · 29.531 days · phasesEspenak, NASA GSFC, Eclipses and the Moon's Orbit
axial tilt · ~1.5° · to the eclipticNASA SVS 5229, Moon Essentials: Seasons; worked out from its numbersBourgoin et al. 2025, Lunar Reference Timescale, arXiv 2507.21597
air · an exosphere only · ~3 × 10⁻¹⁵ bar at nightNASA NSSDCA, Moon Fact SheetNASA Science, Moon Facts
found in it · helium, argon, neon, sodium, potassiumColaprete et al., LADEE UVS instrument paper (NMSU Atmospheres node)NASA, LADEE Spacecraft Finds Neon in Lunar AtmosphereNASA NSSDCA, Moon Fact Sheet
solid inner core · ~240 km radius · weber et al. 2011, modelWeber et al., Seismic Detection of the Lunar Core, NASA NTRS presentationNASA Science, Moon FactsR. C. Weber, Interior of the Moon, NASA NTRS 20130013896
fluid outer core · to ~330 km · modelWeber et al., Seismic Detection of the Lunar Core, NASA NTRS presentation; worked out from its numbersNASA Science, Moon Facts
crust · ~34–43 km · grailTaylor, Wieczorek et al., GRAIL crust, NASA NTRS 20130013613
Apollo's seismometers, working until 1977, recorded thousands of moonquakes: about 7,200 deep ones, roughly 700 to 1,200 km down, and only 28 shallow ones, whose depths are poorly known.R. C. Weber, Interior of the Moon, NASA NTRS 20130013896Nakamura, Jackson & Jackson 2004, More Far-Side Deep Moonquake Nests, NASA NTRSShallow moonquakes and lunar bases, NASA NTRS 19930008250
global field · none todayOran et al. 2020, Science Advances (PMC7723427)A lunar core dynamo limited to the Moon's first ~140 million years (PMC11379625)
crustal magnetism · patches, probably from an ancient dynamoOran et al. 2020, Science Advances (PMC7723427)A lunar core dynamo limited to the Moon's first ~140 million years (PMC11379625)
1959 · luna 2 · first craft to reach itNASA Science, Moon Missions
1966 · luna 9 · first soft landingNASA Science, Moon MissionsNASA Science, Moon Exploration
1969–72 · apollo 11–17 · 12 people on the surfaceNASA Science, Moon ExplorationNASA NSSDCA, The Apollo Program
2009– · lro · mapping at < 1 m a pixelNASA NSSDCA Master Catalog, LROC experimentNASA History, 15 Years Ago: LRO Begins Moon Mapping Mission
2019 · chang'e 4 · first far-side landingNASA Science, Moon MissionsThe Planetary Society, Chang'e-4
2023 · chandrayaan-3 · near the south poleNASA Science, Moon MissionsNASA, LRO Observes Chandrayaan-3 Landing Site
2024 · chang'e 6 · far-side samplesNASA Science, Moon MissionsThe Planetary Society, Chang'e-6
full moon · mag −12.7NASA NSSDCA, Moon Fact Sheet
apparent size · 29.4′ – 33.5′ · apogee to perigeeNASA NSSDCA, Moon Fact Sheet; worked out from its numbers
earthshine · the dark part lit by earth · best at a thin crescentNASA Science, Moon Phases

Mars70 traced

Open its page

A cold desert world of rust-coloured dust, giant volcanoes and dry river valleys — once wet, now home to rovers.NASA, Mars: FactsNASA, 10 Things: Massive Dust Storm on Mars (2018)NASA, Curiosity mission page
diameter · 6,792 km · 0.53 × earthNASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbers
mass · 0.107 earths · 6.42 × 10²³ kgNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
day (sol) · 24 h 39 m 35 sNASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbers
year · 687 days · 1.88 earth yearsNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)NASA, Mars: Facts
from the sun · 228.0 M km · 1.52 auNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
mean surface · −59 °C · ~214 KNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
pressure · ~6 mbar · 0.6% of earth'sNASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbersNASA NSSDCA Earth Fact Sheet
moons · 2 · phobos, deimosNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)NASA, Mars: Facts
width vs earth · 53 · 0.53×NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
gravity vs earth · 38 · 0.38×NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
air pressure · 1 · 0.006×NASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbersNASA NSSDCA Earth Fact Sheet
Mars is half Earth's width with about a tenth of its mass, and it is one of the most explored bodies in the Solar System.NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)NASA, Mars: Facts
Its colour comes from iron oxide — rust — in the fine dust that covers its surface and hangs in its thin air, which is why its sky is butterscotch by day and its sunsets blue.NASA, Mars: FactsNASA, Mount Sharp Panorama in White-Balanced ColorsNASA, 10+ Things: Tour of Storms Across the Solar SystemNASA, What Do Sunrises and Sunsets Look Like on Mars?NASA Photojournal PIA00917, Color Variations in the Sky at Sunset
It holds the Solar System's largest volcano and largest canyon.NASA, Mars: Facts
Olympus Mons, a shield volcano, rises about 21 km above the Martian datum, more than twice the height of Everest; NASA gives more than 40 km from base to summit on one page and 23 km on another.NASA PGDA, The Whole MOLA Catalog; worked out from its numbersESA, Olympus Mons: the caldera in close-upNASA, Mars: FactsNASA SVS 2864, Mauna Loa and Olympus Mons comparison
Valles Marineris, a system of canyons some 4,000 km long and about 9.3 km deep at its deepest, would stretch across the United States.NASA, Mars: Facts
Its southern highlands are ancient and cratered; the northern lowlands are sparsely cratered plains over ancient buried crust.MARSIS radar sounder evidence of buried basins in the northern lowlands of Mars, NatureNASA Photojournal, Martian Dichotomy BoundaryConnerney et al. 1999, Science 284, Magnetic Lineations in the Ancient Crust of Mars
Mars was once wetter.NASA, Mars: Facts
Orbiters have photographed dried river valleys, deltas and lake beds, and rovers have found minerals that form only in water.NASA, Mars: FactsNASA, 10 Things: Massive Dust Storm on Mars (2018)NASA, Delta-Like Fan On Mars Suggests Ancient Rivers Were Persistent
Curiosity has spent more than a decade climbing the layered rocks of Gale crater, a former lake; Perseverance is collecting samples in Jezero crater, once a lake fed by a river delta, for possible return to Earth.NASA, Curiosity mission pageNASA, Curiosity Science HighlightsNASA, Curiosity Rover Finds Clues to Chilly Ancient Mars Buried in RocksNASA, Mars 2020 Perseverance mission page
Today water survives mostly as ice — in the polar caps and buried beneath the ground at mid-latitudes.NASA, Mars: FactsNASA, NASA Is Locating Ice on Mars With This New MapNASA, Frozen: Ice on Earth and Well Beyond
Its air is about 95% carbon dioxide and less than one percent of Earth's surface pressure.NASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbersNASA NSSDCA Earth Fact Sheet
Even so it has weather: dust devils, clouds of water ice, and dust storms that can swell to cover the whole planet, as one did in 2018, ending the Opportunity rover's nearly 15-year mission.NASA Photojournal, Dust Devil DaysNASA Photojournal, A Cloudy Day on MarsNASA, 10 Things: Massive Dust Storm on Mars (2018)NASA, Global Storms on Mars Launch Dust Towers Into the SkyNASA, Record-Setting Opportunity Rover Mission on Mars Comes to End (2019)
The polar caps grow and shrink with the seasons as carbon dioxide freezes out of the air and returns.NASA, Frozen: Ice on Earth and Well BeyondSchmidt et al. 2010, Sublimation of the Martian CO2 Seasonal South Polar Cap (OMEGA/Mars Express) (Planetary and Space Science, Volume 58, Issue 10, August 2010, Pages 1129-1138)
Mars has no global magnetic field today, but parts of its ancient crust are strongly magnetised, a fossil of a dynamo that died long ago; without that shield the solar wind strips gas from its upper atmosphere, which the MAVEN orbiter has measured and which appears to have played a key role in the loss of its early thick atmosphere.NASA, Mars: FactsConnerney et al. 1999, Science 284, Magnetic Lineations in the Ancient Crust of MarsNASA release 15-217, MAVEN: speed of solar wind strippingNASA SVS 4370, MAVEN and the solar wind
InSight's seismometer recorded over a thousand marsquakes and found a liquid iron core; a 2025 analysis of those quakes reports a solid inner core about 613 km in radius inside it (Bi et al., Nature).NASA, Marsquake Data Reveals Lumpy Nature of Red Planet's InteriorNASA, InSight Reveals the Deep Interior of Mars (2021)Bi et al. 2025, Nature, Seismic detection of a 600-km solid inner core in MarsBi et al. 2025, the same paper free to read (PubMed Central)NASA Science, Mars facts: the core is "made of iron, nickel, and sulfur"
Its two small moons, Phobos and Deimos, may be captured asteroids or debris from a giant impact — and if Phobos breaks up on its slow spiral inward, Mars may one day gain a ring.NASA, Moons of MarsNASA, PhobosRosenblatt et al. 2016, Nature Geoscience
equatorial radius · 3,396.2 kmNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)JPL SSD, planetary physical parameters
polar radius · 3,376.2 kmNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
mean density · 3.934 g/cm³NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)JPL SSD, planetary physical parameters
surface gravity · 3.73 m/s² · meanNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
escape velocity · 5.03 km/sNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)JPL SSD, planetary physical parameters
bond albedo · 0.25NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
olympus mons · ~21 km · above the datum (mola); over 40 km base to summit (nasa)NASA PGDA, The Whole MOLA CatalogNASA, Mars: FactsESA, Olympus Mons: the caldera in close-up
valles marineris · ~4,000 km long, ≤ 9.3 km deep · rim to floor (nasa)NASA, Mars: Facts
semi-major axis · 227.956 M km · 1.524 auNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
perihelion · aphelion · 206.650 · 249.261 M kmNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
eccentricity · 0.0935NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
inclination · 1.85°NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
sidereal period · 686.98 daysNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
rotation · 24 h 37 m 22.7 sJPL SSD, planetary physical parameters; worked out from its numbers
axial tilt · 25.19° · seasons like earth's, nearly twice as longNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)NASA, Mars: FactsNASA, 10 Things: Massive Dust Storm on Mars (2018)
carbon dioxide · 95.1NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
nitrogen · 2.59NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
argon · 1.94NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
other · 0.25NASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbers
surface pressure · ~6 mbar · varies with the seasonNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
dust storms · can cover the planet · 2001, 2007, 2018NASA, 10 Things: Massive Dust Storm on Mars (2018)NASA, Global Storms on Mars Launch Dust Towers Into the SkyNASA, Mars: Facts
sky colour · butterscotch by day, blue at sunsetNASA, Mount Sharp Panorama in White-Balanced ColorsNASA, What Do Sunrises and Sunsets Look Like on Mars?
liquid iron core · ~1,650–1,830 km radius · insight seismology; estimates differNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)NASA, InSight Reveals the Deep Interior of Mars (2021)NASA Science, Mars facts: the core is "made of iron, nickel, and sulfur"
solid inner core · 613 ± 67 km radius · reported by bi et al. 2025Bi et al. 2025, Nature, Seismic detection of a 600-km solid inner core in MarsBi et al. 2025, the same paper free to read (PubMed Central)
crust · ~24–72 km · insightKnapmeyer-Endrun et al. 2021, Science 373, 438
marsquakes recorded · 1,319 · insight, 2018–22NASA, Marsquake Data Reveals Lumpy Nature of Red Planet's InteriorNASA, InSight mission page
global field · none todayNASA, Mars: Facts
crustal fields · up to ~1,500 nT at 100 km · mars global surveyorConnerney et al. 1999, Science 284, Magnetic Lineations in the Ancient Crust of Mars
atmosphere lost · to the solar wind · mavenNASA release 15-217, MAVEN: speed of solar wind strippingNASA SVS 4370, MAVEN and the solar wind
phobos · ~27 × 22 × 18 km · 9,378 km out, 7 h 39 mNASA NSSDCA Mars Fact Sheet (updated 19 May 2025); worked out from its numbersNASA, PhobosJPL SSD, planetary satellite mean elements
deimos · ~15 × 12 × 11 km · 23,460 km out, 30.3 hNASA, Deimos; worked out from its numbersNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)JPL SSD, planetary satellite mean elements
1965 · mariner 4 · first close photosNASA, Mariner 4 mission pageNSSDCA Master Catalog, Mariner 4
1976 · viking 1 and 2 · first successful landersNASA, Viking mission pageNASA GISS, Mars24 Sunclock: Mars Landers
1997 · pathfinder · sojourner · first roverNASA, Mars Pathfinder mission pageNASA GISS, Mars24 Sunclock: Mars Landers
2004–18 · spirit · opportunity · roversNASA, Record-Setting Opportunity Rover Mission on Mars Comes to End (2019)NASA, Mars: Facts
2012– · curiosity · gale craterNASA, Curiosity mission page
2018–22 · insight · marsquakesNASA, InSight mission pageNASA, Marsquake Data Reveals Lumpy Nature of Red Planet's Interior
2021– · perseverance · ingenuity · ingenuity: first powered flight on another planetNASA, Ingenuity Mars HelicopterNASA, Mars 2020 Perseverance mission page
2021–22 · zhurong · china's first mars roverNature news 2023, What's happened to China's first Mars rover?NASA GISS, Mars24 Sunclock: Mars Landers
brightest · mag −2.9 · at a close oppositionNASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
apparent size · 3.5″ – 25.6″NASA NSSDCA Mars Fact Sheet (updated 19 May 2025)
next opposition · february 2027British Astronomical Association, Mars opposition 2026-27

Jupiter78 traced

Open its page

More than twice the mass of every other planet combined — hydrogen and helium with no solid surface, wrapped in cloud bands racing at up to 540 km/h.NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024); worked out from its numbersNASA NSSDCA, Planetary Fact SheetNASA Science, Jupiter Facts
diameter · 142,984 km · 11.2 × earthNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024); worked out from its numbers
mass · 317.8 earths · 1.898 × 10²⁷ kgNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
day · 9 h 55 m 30 s · fastest spinNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024); worked out from its numbersNASA Science, Jupiter Facts
year · 11.86 years · 4,332.6 daysNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
from the sun · 778.5 M km · 5.20 auNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
1 bar level · −108 °C · 165 K at 1 barNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)Atreya et al. 2003, Composition, clouds and origin of Jupiter's atmosphereNASA APOD 2020 Nov 23, A Jupiter Vista from Juno
rings · 4 · faint, dustyNASA NSSDCA, Jupiter Rings Fact SheetBurns et al. 2004, in Jupiter (Bagenal et al., eds), ch. 11NASA Science, Jupiter Facts
red spot · ~14,000 km wide · and shrinkingUPC press release on Sánchez-Lavega et al. 2024Sánchez-Lavega et al. 2024, GRL (arXiv)NASA 2024, Hubble Watches Great Red Spot Behave Like a Stress Ball
width vs earth · 100 · 11.2×NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
volume vs earth · 100 · 1,321×NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
gravity at the 1 bar level · 26 · 2.64×NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
sunlight received · 4 · 3.7%NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
Jupiter is the giant of the Solar System: 318 times the mass of Earth and two and a half times the mass of all the other planets put together.NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024); worked out from its numbersNASA NSSDCA, Planetary Fact Sheet
Like the Sun it is made almost entirely of hydrogen and helium, and it has no surface to stand on — what we see are the tops of clouds of ammonia ice, tinted cream, ochre and brown by compounds no one has yet pinned down, and combed into light zones and dark belts by jet streams that blow alternately east and west.NASA Science, Jupiter FactsNASA APOD 2020 Nov 23, A Jupiter Vista from Juno
It was very probably the first planet to form, growing a massive core within the Sun's first few million years and then sweeping up gas.NASA Science, Jupiter FactsKruijer et al. 2017, PNAS
One hypothesis — the Grand Tack — has it drifting inward toward the Sun and back out again, scattering material that may explain why Mars is small and the asteroid belt so thin.Walsh et al. 2011, Nature (arXiv)
Whatever its path, its gravity still sculpts the Solar System today: it clears gaps in the asteroid belt, holds a swarm of Trojan asteroids in step with it, and swallowed comet Shoemaker–Levy 9 in July 1994, the first collision of two Solar System bodies that spacecraft were in place to watch.Murray & Holman 2001, The role of chaotic resonances (arXiv)NASA Science, Asteroids: FactsNASA Science, Comet Shoemaker-Levy 9
Its weather includes the largest atmospheric vortex in the Solar System.Parisi et al. 2021, Science, abstract
The Great Red Spot, an anticyclone wider than Earth, has been followed since at least 1831 — and it is shrinking, from about 39,000 km across in 1879 to around 14,000 km by the 2020s; Juno found it reaches 350 to 500 km down.Sánchez-Lavega et al. 2024, GRL (arXiv); worked out from its numbersUPC press release on Sánchez-Lavega et al. 2024NASA 2018, Great Red Spot Getting Taller as it ShrinksParisi et al. 2021, Science, abstractNASA Science, Jupiter Facts
Around each pole Juno discovered a ring of cyclones packed together like a geometric pattern — eight round the north pole, five or six round the south — along with shallow lightning and slushy ammonia hail.Adriani et al. 2018, Nature, abstractNASA/JPL 2019, Juno Navigators Enable Jupiter Cyclone DiscoveryNASA/JPL 2020, Juno Updates Quarter-Century Jupiter Mystery
Deep inside, the pressure squeezes hydrogen into a liquid metal, and the churning of that metal drives the strongest magnetic field of any planet.NASA Science, Jupiter FactsSwRI Mission Juno, Jupiter's MagnetosphereTsang & Jones 2020, Characterising Jupiter's dynamo radius (arXiv) (Earth Planet. Sci. Lett., vol. 530, 115879 (2020))
Its magnetosphere is the largest structure in the Solar System after the Sun's own: it traps lethal radiation belts, lights permanent aurorae at both poles, and hums with radio bursts that its volcanic moon Io helps switch on and off.Bagenal 2024, Magnetosphere of Jupiter (LASP, Univ. Colorado)SwRI Mission Juno, Jupiter's MagnetosphereESA/Hubble heic1613, Vivid auroras in Jupiter's atmosphereNASA Radio Jove, The Jovian Decametric Radio EmissionNASA Science, Juno mission page
On the listen channel, Juno crosses the bow shock, the shock wave in front of that magnetic field.NASA/JPL PIA20753, via PDS Ring-Moon Systems Node
Jupiter's moons changed history: Galileo's sighting of four of them in 1610 was the first proof that not everything circles the Earth.NASA Science, Ganymede: ExplorationESA, Hello Jupiter! How to observe a gas giantNASA Science, Jupiter Moons
One of those four, Europa, hides a salty ocean under its ice that may hold more water than all of Earth's seas — one of the best places to look for life beyond our planet.NASA Science, Europa ClipperNASA Science, Jupiter Facts
NASA's Europa Clipper and ESA's JUICE are on their way, due in 2030 and 2031, and Juno has been in orbit since 2016.NASA Science, Europa ClipperESA, JuiceNASA Science, Juno mission pageNASA Science, Juno stories (Jul 2026 items; Thebe pass 1 May 2026)
equatorial radius · 71,492 km · (1 bar)NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
polar radius · 66,854 kmNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
flattening · 0.0649NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
mean density · 1.326 g/cm³ · earth 5.51NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024); worked out from its numbers
gravity (mean, 1 bar) · 25.92 m/s² · equator 23.12, pole 27.01NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
escape velocity · 59.5 km/sNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
moment of inertia · 0.254 MR²NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
bond albedo · 0.503 · li et al. 2018; older 0.343Li et al. 2018, Nature CommunicationsNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
internal heat flux · 7.5 W/m² · li et al. 2018Li et al. 2018, Nature Communications
semi-major axis · 778.48 M km · 5.2038 auNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024); worked out from its numbers
perihelion · aphelion · 740.6 · 816.4 M kmNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
eccentricity · 0.0487NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
inclination · 1.304°NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
sidereal period · 11.862 yrNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
rotation (system III) · 9 h 55 m 29.7 sConnerney et al. 2022, JRM33 model (JGR Planets)NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
axial tilt · 3.13° · no extreme seasonsNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)NASA Science, Jupiter Facts
hydrogen · 89.8NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
helium · 10.2NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
methane · ~3,000 ppmNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
ammonia · ~260 ppmNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
ammonia ice clouds · ~0.7 barAtreya et al. 2003, Composition, clouds and origin of Jupiter's atmosphere
ammonium hydrosulfide clouds · ~2 barAtreya et al. 2003, Composition, clouds and origin of Jupiter's atmosphere
water clouds · ~5–7 barAtreya et al. 2003, Composition, clouds and origin of Jupiter's atmosphere
fastest jets · ~150 m/sNASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
great red spot · ~14,000 km wide · 350–500 km deepUPC press release on Sánchez-Lavega et al. 2024Sánchez-Lavega et al. 2024, GRL (arXiv)Parisi et al. 2021, Science, abstractNASA Science, Jupiter Facts
metallic hydrogen · below ~10,000 km · modelConnerney et al. 2022, JRM33 model (JGR Planets); worked out from its numbers
dilute core · to ~half the radius · juno gravityLiu et al. 2019, Nature (arXiv)Wahl et al. 2017, GRL (arXiv)NASA Science, Jupiter Facts
central pressure · tens of millions of bar · modelGuillot & Gautier 2015, Giant planets (arXiv)
central temperature · ~20,000–35,000 K · modelHelled & Howard 2024, Giant planet interiors and atmospheres (arXiv)Guillot et al. 2004, in Jupiter (Bagenal et al., eds), ch. 3
Juno's gravity measurements found Jupiter's heavy elements spread through a large, dilute core rather than packed into a small rocky ball — possibly stirred by a giant impact early on.Wahl et al. 2017, GRL (arXiv)Liu et al. 2019, Nature (arXiv)NASA Science, Jupiter Facts
field at the equator · 4.17 gauss · the dipole; earth ~0.31LASP MOP, Juno trajectory information (JRM09 dipole)Connerney et al. 2022, JRM33 model (JGR Planets)NASA NSSDCA, Earth Fact Sheet
magnetic moment · ~20,000 × earthBagenal 2024, Magnetosphere of Jupiter (LASP, Univ. Colorado); worked out from its numbersNASA Goddard, Millennium of Geomagnetism: other planets
tilt · 10.3°LASP MOP, Juno trajectory information (JRM09 dipole)Connerney et al. 2022, JRM33 model (JGR Planets)
reach toward the sun · 3–7 M kmKhurana et al. 2004, in Jupiter (Bagenal et al., eds), ch. 24; worked out from its numbersBagenal 2024, Magnetosphere of Jupiter (LASP, Univ. Colorado)
tail · past saturn's orbitBagenal 2024, Magnetosphere of Jupiter (LASP, Univ. Colorado)
io's plasma · ~1 tonne/sBagenal 2024, Magnetosphere of Jupiter (LASP, Univ. Colorado)Thomas et al. 2004, in Jupiter (Bagenal et al., eds), ch. 23
io · 3,643 km · volcanoesNASA NSSDCA, Jovian Satellite Fact Sheet; worked out from its numbersNASA Science, Io
europa · 3,122 km · oceanNASA NSSDCA, Jovian Satellite Fact Sheet; worked out from its numbersNASA Science, Europa Clipper
ganymede · 5,262 km · largest moonNASA NSSDCA, Jovian Satellite Fact Sheet; worked out from its numbersNASA Science, Jupiter Moons
callisto · 4,821 km · crateredNASA NSSDCA, Jovian Satellite Fact Sheet; worked out from its numbersNASA Science, Callisto
rings (voyager 1, 1979) · halo · main · 2 gossamer · 89,400–280,000 kmNASA NSSDCA, Jupiter Rings Fact SheetBurns et al. 2004, in Jupiter (Bagenal et al., eds), ch. 11NASA Science, Jupiter Facts
1973 · pioneer 10 · first flybyNASA Science, Pioneer 10
1979 · voyager 1 and 2 · rings, io's volcanoesNASA 2014, Hubble Shows Great Red Spot Is Smaller Than Ever MeasuredNASA Science, IoNASA Science, Jupiter Facts
1995–2003 · galileo · first orbiter + probeNASA Science, Galileo missionNASA/JPL 2020, Juno Updates Quarter-Century Jupiter Mystery
2016– · juno · polar orbiterNASA Science, Juno mission page
2030 · europa clipper · arrivesNASA Science, Europa Clipper
2031 · juice · arrivesESA, Juice
brightest · mag −2.94NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
apparent size · 30.5″ – 50.1″NASA NSSDCA, Jupiter Fact Sheet (updated 2 Oct 2024)
binoculars · up to four galilean moonsNASA Night Sky Network, Spot the King of PlanetsNASA Watch the Skies blog, 16 Sep 2022
small telescope · cloud bands, and the red spot if powerful enoughNASA Night Sky Network, Spot the King of Planets

Saturn72 traced

Open its page

The ringed planet — light enough to float on water, with a hexagon at its north pole and rings of ice 270,000 km across but mostly only metres thick.NASA, Saturn: Facts; worked out from its numbersNASA NSSDCA, Saturnian Rings Fact Sheet
diameter · 120,536 km · 9.45 × earthNASA NSSDCA, Saturn Fact Sheet; worked out from its numbers
mass · 95.2 earths · 5.68 × 10²⁶ kgNASA NSSDCA, Saturn Fact Sheet
day · 10 h 33 m 38 s · ring seismologyMankovich et al. 2019, ApJ (arXiv:1805.10286)
year · 29.4 yearsNASA, Saturn: Facts
from the sun · 1,432 M km · 9.57 auNASA NSSDCA, Saturn Fact Sheet
1 bar level · −139 °C · 134 K at 1 barNASA NSSDCA, Saturn Fact SheetCassini Exploration of the Planet Saturn: A Comprehensive Review (PMC8753610)
density · 0.687 g/cm³ · less than waterNASA NSSDCA, Saturn Fact Sheet; worked out from its numbersNASA, Saturn: Facts
rings · 3 main · A, B, C; fainter D to GNASA, Saturn: Facts
width vs earth · 85 · 9.45×NASA NSSDCA, Saturn Fact Sheet
gravity at the 1 bar level · 46 · 1.14×NASA NSSDCA, Saturn Fact Sheet
sunlight received · 2 · 1.1%NASA NSSDCA, Saturn Fact Sheet
Saturn is the second-largest planet, nine and a half times Earth's width, yet so light for its size that it would float in a big enough ocean: its average density is less than that of water.NASA, Saturn: FactsNASA NSSDCA, Saturn Fact Sheet
Like Jupiter it is mostly hydrogen and helium with no solid surface, but its clouds lie under a thick haze, in soft shades of yellow, brown and grey.NASA, Saturn: FactsNASA PIA09910 (PDS Rings Node)
It spins so fast — a day of about 10 hours 34 minutes — that it bulges at the equator, about eleven percent wider there than from pole to pole.NASA NSSDCA, Saturn Fact Sheet; worked out from its numbersMankovich et al. 2019, ApJ (arXiv:1805.10286)NASA, Flattened Crescent
Its rings are the most spectacular in the Solar System: three main rings, A, B and C, and the fainter D, E, F and G, lettered in the order they were found.NASA, Saturn: Facts
The main rings span about 270,000 km yet in most places are only about ten metres thick.NASA NSSDCA, Saturnian Rings Fact Sheet; worked out from its numbersNASA, Saturn: Facts
They are made of countless pieces of water ice, from grains of dust to boulders the size of houses, constantly colliding.NASA, Saturn: FactsNASA, Cassini "CAT scan" maps clumps in Saturn's rings: "constantly colliding"Kempf et al. 2023, Science Advances
The Cassini Division, a 4,800 km gap, lies just outside the B ring's edge, which is held by a resonance with the moon Mimas; the small shepherd moon Prometheus helps keep the narrow F ring in place.NASA Photojournal, Looming Saturn; worked out from its numbersNASA NSSDCA, Saturnian Rings Fact SheetSpitale & Porco 2010, AJ (arXiv:0912.3489)NASA, PrometheusNASA, Pandora
How old the rings are is still argued over.Kempf et al. 2023, Science Advances
Cassini's last orbits, threading between the rings and the planet in 2017, measured their mass; with the rings also looking relatively clean, that suggests they may be no more than a few hundred million years old — far younger than Saturn — though other models allow them to be ancient and kept clean.Iess et al. 2019, ScienceKempf et al. 2023, Science AdvancesHyodo et al. 2024, Nature Geoscience
They are also slowly raining onto the planet.NASA, Blame it on the Rain (from Saturn's Rings)NASA, Groundbreaking Science Emerges from Ultra-Close Orbits of Saturn
At Saturn's north pole sits a six-sided jet stream, a hexagon about 30,000 km across, first seen by Voyager and watched by Cassini as it changed colour with the seasons.NASA, Saturn: FactsNASA, Changing Colors in Saturn's NorthSromovsky et al. 2021, Saturn's north polar colour from Cassini VIMS and ISS (arXiv:2108.00322) (Icarus 362 (2021) 114409)
Roughly every Saturnian year a great white storm erupts; the last, in 2010–11, wrapped right round the planet.Caltech, Explaining Saturn's Great White SpotsCassini Exploration of the Planet Saturn: A Comprehensive Review (PMC8753610)
JPL's discovery table lists 293 known moons of Saturn, 292 of them with orbital elements (both read 31 October 2026), more than any other planet, and two of them are among the most interesting worlds we know.JPL SSD, Planetary Satellite Discovery CircumstancesJPL SSD, Planetary Satellite Mean ElementsNASA, Saturn: Facts
Titan, larger than Mercury, has a thick nitrogen atmosphere, rain and lakes of liquid methane; the Huygens probe landed there in 2005, and NASA's Dragonfly rotorcraft is to follow in the 2030s.NASA, Titan: FactsNASA, TitanNASA, Saturn's MoonsNASA, Saturn: ExplorationNASA OIG report IG-25-011, Dragonfly
Enceladus sprays geysers of salty water from a global ocean, through cracks at its south pole, feeding Saturn's E ring.NASA, Enceladus
equatorial radius · 60,268 km · (1 bar)NASA NSSDCA, Saturn Fact Sheet
polar radius · 54,364 kmNASA NSSDCA, Saturn Fact Sheet
flattening · 0.0980NASA NSSDCA, Saturn Fact Sheet
mean density · 0.687 g/cm³NASA NSSDCA, Saturn Fact SheetJPL SSD, Planetary Satellite Physical Parameters
gravity (mean, 1 bar) · 11.19 m/s² · equator 8.96, pole 12.14NASA NSSDCA, Saturn Fact Sheet
escape velocity · 35.5 km/sNASA NSSDCA, Saturn Fact Sheet
bond albedo · 0.34 voyager · 0.41 cassiniNASA NSSDCA, Saturn Fact SheetWang et al. 2024, Nature Communications
gives off · 2.39 ± 0.21 × what it absorbs · wang et al. 2024Wang et al. 2024, Nature Communications; worked out from its numbers
semi-major axis · 1,432.0 M km · 9.57 auNASA NSSDCA, Saturn Fact Sheet
perihelion · aphelion · 1,357.6 · 1,506.5 M kmNASA NSSDCA, Saturn Fact Sheet
eccentricity · 0.0520NASA NSSDCA, Saturn Fact Sheet
inclination · 2.49°NASA NSSDCA, Saturn Fact Sheet
sidereal period · 29.447 yrNASA NSSDCA, Saturn Fact Sheet
rotation · 10 h 33 m 38 s · mankovich et al. 2019Mankovich et al. 2019, ApJ (arXiv:1805.10286)
axial tilt · 26.73° · rings open and close over its yearNASA NSSDCA, Saturn Fact SheetNASA, Hubble Views Saturn Ring-Plane Crossing
hydrogen · 96.3NASA NSSDCA, Saturn Fact Sheet
helium · 3.25NASA NSSDCA, Saturn Fact Sheet
other · 0.45NASA NSSDCA, Saturn Fact Sheet; worked out from its numbers
methane · ~4,500 ppmNASA NSSDCA, Saturn Fact Sheet
fastest jets · ~500 m/s · at the equatorNASA, Saturn: Facts
north polar hexagon · ~30,000 km acrossNASA, Saturn: Facts
great white spots · about once a saturnian year · last 2010–11Caltech, Explaining Saturn's Great White SpotsCassini Exploration of the Planet Saturn: A Comprehensive Review (PMC8753610)
dilute core · to ~60% of the radius · mankovich & fuller 2021, ring seismologyMankovich & Fuller 2021, Nature AstronomyMankovich & Fuller 2021, the same paper free to read (arXiv)
metallic hydrogen · below ~20,000 km · modelDepth of the dynamo region in Saturn, MNRAS 2019; worked out from its numbersLiu et al. 2007, Constraints on Deep-seated Zonal Winds Inside Jupiter and Saturn (arXiv:0711.3922)
Waves in Saturn's rings, set ringing by the planet's own oscillations, let Cassini sound its interior: its core is diffuse, not a hard ball.Mankovich & Fuller 2021, Nature AstronomyMankovich & Fuller 2021, the same paper free to read (arXiv)
field at the equator · 0.21 gaussNASA NSSDCA, Saturn Fact Sheet
tilt · < 0.01° · aligned with the spin axisNASA, Groundbreaking Science Emerges from Ultra-Close Orbits of Saturn
reach toward the sun · ~22–27 saturn radiiAchilleos et al. 2008, JGR Space Physics
aurorae · at both poles · hubble, cassiniESA, Hubble observes energetic lightshow at Saturn's north pole
titan · 5,150 km · thick air, methane lakesJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA, Saturn: Facts
rhea · 1,527 kmJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbers
iapetus · 1,469 km · two-tonedJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA, Iapetus
dione · 1,123 kmJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbers
tethys · 1,062 kmJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbers
enceladus · 504 km · geysers, oceanJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA, Enceladus
mimas · 396 km · herschel craterJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA, Mimas
rings · d · c · b · a · f · g · e · main: a, b, c; 66,900 km to ~480,000 kmNASA NSSDCA, Saturnian Rings Fact SheetNASA, Saturn: Facts
1979 · pioneer 11 · first flybyNASA, Saturn: Exploration
1980–81 · voyager 1 and 2 · flybysNASA, Saturn: Exploration
2004–17 · cassini · 13 years in orbitNASA, Cassini-Huygens
2005 · huygens · landed on titanNASA, Titan: Facts
2030s · dragonfly · to titanNASA, TitanNASA OIG report IG-25-011, Dragonfly
brightest · mag −0.55NASA NSSDCA, Saturn Fact Sheet
apparent size · 14.5″ – 19.9″ · rings ~2.3× widerNASA NSSDCA, Saturn Fact SheetNASA NSSDCA, Saturnian Rings Fact Sheet
small telescope · the rings and titanNASA Watch the Skies, Saturn Shines This Week (2023)

Uranus67 traced

Open its page

A pale greenish-blue ice giant tipped on its side, with thin dark rings and the coldest air of any planet.NASA, Uranus: FactsIrwin et al. 2024, MNRAS 527, 11521Schombert, University of Oregon AST121 lecture 20
diameter · 51,118 km · 4.0 × earthNASA NSSDCA, Uranus Fact Sheet; worked out from its numbers
mass · 14.5 earths · 8.68 × 10²⁵ kgNASA NSSDCA, Uranus Fact SheetJPL SSD, Planetary Physical Parameters
day · 17 h 14 m 52 s · retrogradeLamy et al. 2025, Nature AstronomyNASA, Hubble Helps Determine Uranus Rotation RateNASA NSSDCA, Uranus Fact Sheet
year · 84.0 yearsNASA NSSDCA, Uranus Fact Sheet
from the sun · 2,867 M km · 19.2 auNASA NSSDCA, Uranus Fact SheetJPL SSD, Planetary Physical Parameters
coldest air · −224 °C · 49 KNASA, Uranus: Facts
axial tilt · 97.8° · on its sideNASA NSSDCA, Uranus Fact SheetNASA, Uranus: Facts
rings · 13 · most dark, narrowNASA, Uranus: FactsNASA NSSDCA, Uranus Rings Fact Sheet
width vs earth · 40 · 4.0×NASA NSSDCA, Uranus Fact Sheet
gravity at the 1 bar level · 92 · 0.92×NASA NSSDCA, Uranus Fact Sheet
sunlight received · 1 · 0.27%NASA NSSDCA, Uranus Fact Sheet; worked out from its numbers
Uranus was the first planet discovered with a telescope, found by William Herschel on 13 March 1781 — at first he thought it was a comet or a star.NASA, Uranus: FactsNASA NSSDCA, Uranus Fact Sheet
It is an ice giant: beneath a hydrogen and helium atmosphere tinted pale greenish blue by methane, which absorbs red light, most of its mass is a hot, dense fluid of water, methane and ammonia 'ices' around a small rocky core.NASA, Uranus: FactsIrwin et al. 2024, MNRAS 527, 11521
Its tilt is unique.NASA Science, Uranus: FactsNASA Science, Uranus
Its axis lies 98° from upright, so it rolls round the Sun on its side.NASA NSSDCA, Uranus Fact SheetNASA, Uranus: Facts
Each pole gets about 42 years of continuous sunlight followed by 42 years of night; when Voyager 2 flew past in 1986 the south pole pointed almost straight at the Sun.University of Wisconsin-Madison news, SromovskyNASA NSSDCA image catalog, Uranus - Voyager 2Cartwright et al. 2021, science case for the Uranian satellites
A giant collision early in its history is the most common explanation.Ice Giants review, 2025Rufu & Canup 2022, Tilting Impact
It is also odd inside.Irwin et al. 2025, MNRAS 540, The bolometric Bond albedo and energy balance of Uranus (arXiv abstract)NASA Science, Uranus: Facts
Uranus gives off only about 13–15% more heat than it absorbs from the Sun, where the other giants give off more than twice as much, and its atmosphere is the coldest of any planet, falling to about −224 °C.Wang et al. 2025, GRLGL115660 (NTRS full text); worked out from its numbersIrwin et al. 2025, MNRASSchombert, University of Oregon AST121 lecture 20NASA, Uranus: Facts
Its magnetic field is tilted 59° from its spin axis and offset from the centre by a third of its radius, so it tumbles as the planet turns.NASA NSSDCA, Uranus Fact SheetNASA, Uranus: FactsGeorgia Tech news on Cao & Paty 2017
Its 13 known rings are faint.NASA, Uranus: Facts
The first were found in 1977, when they blocked the light of a star passing behind the planet; Voyager 2 added more in 1986 and Hubble the outer two in 2003–05.NASA, Uranus: ExplorationSmithsonian National Air and Space Museum, UranusNASA, Voyager 2NASA, Hubble Discovers New Rings and Moons Around Uranus (2005)
The inner rings are mostly narrow and dark; the outer two are wide, one reddish and one blue.NASA, Uranus: FactsNASA NSSDCA, Uranus Rings Fact Sheet
Its moons are named after characters from Shakespeare and Pope; the five largest — Miranda, Ariel, Umbriel, Titania and Oberon — mostly show canyons, faults and signs of past activity, though Umbriel's surface is dark and ancient.NASA, Uranus: MoonsCartwright et al. 2021, science case for the Uranian satellitesNASA, UmbrielNASA, TitaniaNASA, OberonNASA, Ariel
Miranda's patchwork face, with cliffs estimated at up to 20 km high, is one of the strangest in the Solar System.NASA, MirandaNASA APOD 2011 April 4, Verona RupesNASA Space Place, Jumping the Tallest Cliff
Only Voyager 2 has visited, flying past on 24 January 1986, and it saw only the southern halves of the moons, the north being in darkness.NASA, Uranus: ExplorationCartwright et al. 2021, science case for the Uranian satellites
Since then Hubble, Keck and the James Webb Space Telescope have watched its storms and clouds as Uranus moves through its seasons; in 2025 Hubble measurements refined its day to 17 hours 14 minutes 52 seconds.de Pater et al. 2015, Record-breaking Storm Activity on Uranus in 2014NASA, Webb Rings in Holidays with Ringed Planet UranusNASA, Uranus: FactsLamy et al. 2025, Nature AstronomyNASA, Hubble Helps Determine Uranus Rotation Rate
A dedicated orbiter and probe is the highest-priority large mission in the National Academies' planetary science decadal survey.National Academies, decadal survey news release, 2022
equatorial radius · 25,559 km · (1 bar)NASA NSSDCA, Uranus Fact SheetJPL SSD, Planetary Physical Parameters
polar radius · 24,973 kmNASA NSSDCA, Uranus Fact Sheet
mean density · 1.27 g/cm³NASA NSSDCA, Uranus Fact Sheet; worked out from its numbersJPL SSD, Planetary Physical Parameters
gravity (mean, 1 bar) · 9.01 m/s² · equator 8.69, pole 9.19NASA NSSDCA, Uranus Fact Sheet
escape velocity · 21.3 km/sNASA NSSDCA, Uranus Fact Sheet
bond albedo · 0.30–0.35NASA NSSDCA, Uranus Fact SheetIrwin et al. 2025, MNRAS
gives off · ~1.13–1.15 × what it absorbs · the other giants: over 2×; wang et al. 2025, irwin et al. 2025Wang et al. 2025, GRLGL115660 (NTRS full text); worked out from its numbersIrwin et al. 2025, MNRAS
semi-major axis · 2,867.0 M km · 19.17 auNASA NSSDCA, Uranus Fact Sheet
eccentricity · 0.0469NASA NSSDCA, Uranus Fact Sheet
inclination · 0.77°NASA NSSDCA, Uranus Fact Sheet
sidereal period · 84.0 yrNASA NSSDCA, Uranus Fact Sheet
rotation · 17 h 14 m 52 s, retrograde · lamy et al. 2025Lamy et al. 2025, Nature Astronomy; worked out from its numbersNASA, Hubble Helps Determine Uranus Rotation RateNASA NSSDCA, Uranus Fact Sheet
axial tilt · 97.77° · 42-year days and nights at the polesNASA NSSDCA, Uranus Fact SheetUniversity of Wisconsin-Madison news, Sromovsky
hydrogen · 82.5NASA NSSDCA, Uranus Fact Sheet
helium · 15.2NASA NSSDCA, Uranus Fact Sheet
methane · 2.3NASA NSSDCA, Uranus Fact Sheet
temperature at 1 bar · −197 °C · 76 KNASA NSSDCA, Uranus Fact Sheet
coldest point · −224 °C · 49 K, nasa; voyager 2 radio: 53 K at the tropopauseNASA, Uranus: FactsNASA, 10 Things: Planetary AtmospheresLindal et al. 1987, JGR (abstract, EarthRef)Helled, Nettelmann & Guillot 2020, Uranus and Neptune review
colour · pale greenish blue · methane absorbs redNASA, Uranus: FactsIrwin et al. 2024, MNRAS 527, 11521
'icy' mantle · water, methane, ammonia fluid · modelHelled et al. 2011, Interior Models of Uranus and NeptuneNASA, Uranus: Facts
rocky core · nearly zero to ~5 earth masses · modelIce Giants review, 2025
No spacecraft has sounded Uranus's interior; models are built on its mass, size, spin and gravity field from Voyager 2, the rings' precession and the moons' orbits.Helled, Nettelmann & Guillot 2020, Uranus and Neptune review
field at the surface · 0.1–1.0 gauss · nssdcaNASA NSSDCA, Uranus Fact Sheet
dipole moment · 0.228 gauss × radius³ · gsfc-o3NASA NSSDCA, Uranus Fact Sheet
tilt · 59° · to the spin axis, gsfc-o3NASA NSSDCA, Uranus Fact Sheet
offset from centre · ~0.35 of its radius · gsfc-o3; ness et al. 1986 fit ~0.3NASA NSSDCA, Uranus Fact SheetNess et al. 1986, Science 233 (NTRS abstract)
titania · 1,578 km · largestJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA NSSDCA, Uranian Satellite Fact SheetNASA, Titania
oberon · 1,523 kmJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA NSSDCA, Uranian Satellite Fact Sheet
umbriel · 1,169 km · darkestJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA NSSDCA, Uranian Satellite Fact SheetNASA, Umbriel
ariel · 1,158 kmJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbers
miranda · 472 km · 20 km cliffsJPL SSD, Planetary Satellite Physical Parameters; worked out from its numbersNASA APOD 2011 April 4, Verona Rupes
rings · 13 · 41,800–51,150 km (the narrow rings; faint zeta lies further in); out to ~106,000 kmNASA NSSDCA, Uranus Rings Fact Sheet; worked out from its numbersPDS Ring-Moon Systems Node, Vital Statistics for UranusNASA, Uranus: Facts
1781 · william herschel · discovered itNASA NSSDCA, Uranus Fact SheetNASA, Uranus: Exploration
1977 · kuiper airborne observatory · first rings foundNASA, Uranus: ExplorationSmithsonian National Air and Space Museum, Uranus
1986 · voyager 2 · the only visitNASA, Uranus: Exploration
2003–05 · hubble · outer two ringsNASA, Hubble Discovers New Rings and Moons Around Uranus (2005)NASA, Uranus: Exploration
brightest · mag 5.4 · just visible to the eye in a dark skyNASA NSSDCA, Uranus Fact SheetNASA, Skywatching
apparent size · 3.3″ – 4.1″NASA NSSDCA, Uranus Fact Sheet

Neptune59 traced

Open its page

The farthest planet, found by mathematics before it was seen — the windiest world in the solar system, with a moon that orbits backwards.NASA Science, Neptune factsESO press release eso2502, winds on WASP-127bNASA NSSDCA, Neptune Fact Sheet
diameter · 49,528 km · 3.9 × earthNASA Science, Neptune factsNASA NSSDCA, Neptune Fact Sheet
mass · 17.1 earths · 1.02 × 10²⁶ kgNASA NSSDCA, Neptune Fact Sheet; worked out from its numbers
day · 16 h 6 mNASA NSSDCA, Neptune Fact Sheet; worked out from its numbersJPL SSD, planetary physical parameters
year · 164.8 yearsNASA NSSDCA, Neptune Fact SheetJPL SSD, planetary physical parameters
from the sun · 4,515 M km · 30.2 auNASA NSSDCA, Neptune Fact Sheet
1 bar level · −201 °C · 72 K at 1 barNASA NSSDCA, Neptune Fact SheetFitzpatrick et al. 2014, Dispersion in Neptune's Zonal Wind Velocities
winds · up to ~2,100 km/h · fastest in the solar systemNASA NSSDCA, Neptune Fact Sheet; worked out from its numbersNASA Science, Neptune factsESO press release eso2502, winds on WASP-127b
rings · 5 main · with arcsNASA Science, Neptune facts
width vs earth · 39 · 3.9×NASA NSSDCA, Neptune Fact Sheet
gravity at the 1 bar level · 100 · 1.15×NASA NSSDCA, Neptune Fact Sheet
sunlight received · 1 · 0.11%NASA NSSDCA, Neptune Fact Sheet; worked out from its numbers
Neptune was the first planet found by prediction.NASA Science, Neptune facts
Irregularities in the orbit of Uranus led Urbain Le Verrier to calculate where an unseen planet must be, and on 23 September 1846 Johann Galle found it at the Berlin Observatory within a degree of the spot.NASA Science, Neptune factsNASA NSSDCA, Neptune Fact SheetVatican Observatory, Catholic Astronomers and the Discovery of Neptune
It is the farthest planet from the Sun, thirty times as far as Earth, and has completed only one orbit since its discovery, in 2011.NASA Science, Neptune factsNASA Science, Neptune exploration timeline
Like Uranus it is an ice giant — a deep fluid mantle of water, ammonia and methane under a hydrogen and helium atmosphere.NASA Science, Neptune facts
For decades it was pictured as a deep blue, but in 2024 a re-analysis of Voyager and modern images showed that its true colour is a blue-green much closer to Uranus, only a little bluer; the vivid blue came from images whose contrast had been boosted.Irwin et al. 2024, MNRAS 527, 11521NASA Science, Neptune facts
Despite receiving a thousandth of the sunlight Earth does, Neptune has the fastest winds measured in the solar system, up to about 2,100 km/h.NASA NSSDCA, Neptune Fact Sheet; worked out from its numbersNASA Science, Neptune factsESO press release eso2502, winds on WASP-127b
Voyager 2 saw a Great Dark Spot the size of Earth in 1989; when Hubble looked again five years later it had gone, and other dark spots have come and gone since.NASA Science, Neptune factsHammel et al. 1995, Science 268, 1740NASA Science, Neptune exploration timeline
Neptune radiates about 2.6 times the energy it absorbs from the Sun, an internal heat source thought to feed its storms.Pearl & Conrath 1991, JGR 96, 18921; worked out from its numbersHueso et al. 2020, Convective storms and atmospheric vertical structure in Uranus and Neptune, arXiv 2111.15494 (Philosophical Transactions of the Royal Society A, Volume 378, Issue 2187, article id.20190476 (2020))Clément et al. 2024, Storms and convection on Uranus and Neptune, 3D cloud-resolving model (A&A 690, A227 (2024))
Its largest moon, Triton, orbits backwards, against Neptune's spin — a sign that it was an object from the Kuiper belt captured by Neptune's gravity.NASA Science, TritonNASA Science, Neptune facts
Voyager 2 found geysers erupting from its frozen nitrogen surface and a thin atmosphere; tides are slowly drawing it inward, and in billions of years it may fall into Neptune, leaving a set of rings.NASA Science, TritonSoderblom et al. 1990, Science 250, 410NASA Science, Neptune factsvan Woerkom 2024, The trans- and post-capture orbital evolution of Triton
Neptune's rings are faint and dusty, and the outermost, named Adams, holds four bright clumps or 'arcs' — Liberté, Égalité, Fraternité and Courage — that should spread out but do not, probably held in place by the small moon Galatea.NASA Science, Neptune factsNASA, New Webb Image Captures Clearest View of Neptune's Rings in Decades
Voyager 2's flyby on 25 August 1989 remains the only visit; in 2022 the James Webb Space Telescope took the clearest view of the rings in more than three decades, and the first in infrared.NASA, New Webb Image Captures Clearest View of Neptune's Rings in DecadesNASA Science, Neptune exploration timelineIrwin et al. 2024, MNRAS 527, 11521
equatorial radius · 24,764 km · (1 bar)NASA NSSDCA, Neptune Fact SheetJPL SSD, planetary physical parameters
polar radius · 24,341 kmNASA NSSDCA, Neptune Fact Sheet
mean density · 1.638 g/cm³ · the densest giantNASA NSSDCA, Neptune Fact SheetJPL SSD, planetary physical parametersNASA Science, Neptune facts
gravity (mean, 1 bar) · 11.27 m/s² · equator 11.00, pole 11.41NASA NSSDCA, Neptune Fact Sheet
escape velocity · 23.5 km/sNASA NSSDCA, Neptune Fact Sheet
bond albedo · 0.29NASA NSSDCA, Neptune Fact SheetPearl & Conrath 1991, JGR 96, 18921
heat radiated · ~2.6× the sunlight it absorbsPearl & Conrath 1991, JGR 96, 18921; worked out from its numbersHueso et al. 2020, Convective storms and atmospheric vertical structure in Uranus and Neptune, arXiv 2111.15494 (Philosophical Transactions of the Royal Society A, Volume 378, Issue 2187, article id.20190476 (2020))
semi-major axis · 4,515.0 M km · 30.18 auNASA NSSDCA, Neptune Fact Sheet
eccentricity · 0.0097NASA NSSDCA, Neptune Fact Sheet
inclination · 1.77°NASA NSSDCA, Neptune Fact Sheet
sidereal period · 164.8 yr · first full orbit since discovery: 2011NASA NSSDCA, Neptune Fact SheetNASA Science, Neptune exploration timeline
rotation · 16 h 6 m 36 sNASA NSSDCA, Neptune Fact Sheet; worked out from its numbersJPL SSD, planetary physical parameters
axial tilt · 28.32°NASA NSSDCA, Neptune Fact Sheet
hydrogen · 80NASA NSSDCA, Neptune Fact Sheet
helium · 19NASA NSSDCA, Neptune Fact Sheet
methane · 1.5NASA NSSDCA, Neptune Fact Sheet
temperature at 1 bar · −201 °C · 72 KNASA NSSDCA, Neptune Fact Sheet
fastest winds · up to ~580 m/s · voyager fit ~400 m/s retrograde at the equatorNASA NSSDCA, Neptune Fact Sheet; worked out from its numbersFitzpatrick et al. 2014, Dispersion in Neptune's Zonal Wind VelocitiesIce Giants review, arXiv 2504.18219
great dark spot · 1989 · gone by 1994Hammel et al. 1995, Science 268, 1740
true colour · blue-green, close to uranus · irwin et al. 2024Irwin et al. 2024, MNRAS 527, 11521
'icy' mantle · water, ammonia, methane fluid · modelNASA Science, Neptune factsIce Giants review, arXiv 2504.18219Helled et al. 2020, Space Sci Rev, Uranus and Neptune
rocky core · nearly 0 to ~5 earth masses · model; nasa says ~1Ice Giants review, arXiv 2504.18219NASA Science, Neptune facts
field at the surface · 0.1–0.9 gauss · nssdcaNASA NSSDCA, Neptune Fact Sheet
dipole moment · 0.142 gauss × radius³ · gsfc-o8NASA NSSDCA, Neptune Fact Sheet
tilt · 47° · to the spin axis, gsfc-o8NASA NSSDCA, Neptune Fact SheetNASA Science, Neptune facts
offset from centre · ~0.49 of its radius · gsfc-o8; ness et al. 1989 fit 0.55NASA NSSDCA, Neptune Fact SheetNess et al. 1989, Science 246, 1473
triton · 2,707 km · retrograde, geysersNASA NSSDCA, Neptunian Satellite Fact Sheet; worked out from its numbersNASA Science, Triton
proteus · ~420 km · one of the darkest objects in the solar systemNASA NSSDCA, Neptunian Satellite Fact Sheet; worked out from its numbersJPL SSD, planetary satellite physical parametersNASA Science, Proteus
nereid · ~340–357 km · orbit eccentricity 0.75, among the highest of any moonNASA NSSDCA, Neptunian Satellite Fact Sheet; worked out from its numbersJPL SSD, planetary satellite physical parametersKiss et al. 2016, MNRAS, Nereid from spaceKiss et al. 2016, the same paper free to read (arXiv)NASA Science, Nereid
rings · galle · le verrier · lassell · arago · adams · adams has arcsNASA Science, Neptune factsNASA NSSDCA, Neptunian Rings Fact Sheet
1846 · le verrier and galle · predicted and foundNASA Science, Neptune factsNASA NSSDCA, Neptune Fact Sheet
1989 · voyager 2 · the only visitNASA Science, Neptune exploration timeline
2022 · jwst · rings in infraredNASA, New Webb Image Captures Clearest View of Neptune's Rings in DecadesNASA Science, Neptune exploration timeline
brightest · mag 7.7 · binocularsNASA NSSDCA, Neptune Fact SheetJPL Night Sky Network, Neptune at opposition event
apparent size · 2.2″ – 2.4″NASA NSSDCA, Neptune Fact Sheet

Pluto59 traced

Open its page

A small world of nitrogen ice and water-ice mountains with a vast glacier in its bright heart, revealed by New Horizons in 2015.Stern et al. 2018, ARA&AStern et al. 2015, ScienceMoore et al. 2016, Science 351, 1284
diameter · 2,377 km · 0.19 × earthNimmo et al. 2017, Icarus; worked out from its numbersNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)Stern et al. 2018, ARA&A
mass · 0.0022 earths · 1.30 × 10²² kgNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
day · 6 d 9 h 18 m · retrogradeNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersNASA Science, Pluto facts
year · 248 yearsNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
from the sun · 29.7–49.3 au · 35.6 au on 31 oct 2026NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersJPL Horizons, target 999, read 2026-11-01NASA Science, Pluto facts
surface · ~−230 °C · ~40 KNASA Science, Pluto facts; worked out from its numbersStern et al. 2018, ARA&A
moons · 5 · charon the largestNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)NASA Science, Pluto facts
discovered · 18 feb 1930 · clyde tombaughNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
width vs earth · 19 · 0.19×NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
gravity vs earth · 6 · 0.063×NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
Pluto was found on 18 February 1930 by Clyde Tombaugh, a 24-year-old at Lowell Observatory, comparing photographs taken nights apart for something that moved.NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersNew Mexico State University Library, Clyde W. Tombaugh chronologyLinda Hall Library, Scientist of the Day: Clyde TombaughLowell Observatory, Pluto Discovery Dome
For 76 years it was counted the ninth planet.NASA Science, Pluto facts; worked out from its numbersIAU 2006 General Assembly, result of the resolution votes
In 2006, after the discovery of Eris and other worlds like it beyond Neptune, the International Astronomical Union created the category of dwarf planet, with Pluto among its first members: one of the millions of small icy objects astronomers think lie in the Kuiper belt.NASA Science, ErisIAU 2006 General Assembly, result of the resolution votesNASA Science, Kuiper Belt facts
When NASA's New Horizons flew past on 14 July 2015 — after nine and a half years of travel — it revealed a world far more active than anyone expected.Stern et al. 2018, ARA&A; worked out from its numbersNASA History, 15 Years Ago: New Horizons Launched
The bright heart of Tombaugh Regio holds Sputnik Planitia, a basin 1,000 km or more across filled with nitrogen ice that slowly churns in cells like a lava lamp, its surface so young it has no craters at all.Stern et al. 2015, ScienceStern et al. 2018, ARA&ANimmo et al. 2016, Nature 540, 94NASA Scientific Visualization Studio, Pluto's convection
Around it rise mountains of water ice several kilometres high, hard as rock at these temperatures.NASA Science, Pluto factsMoore et al. 2016, Science 351, 1284
Pluto has a thin atmosphere of nitrogen with methane and carbon monoxide, about a hundred-thousandth of Earth's surface pressure, and New Horizons saw it layered with blue haze extending more than 200 km up.NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersStern et al. 2018, ARA&A
Whether it freezes out as Pluto moves away from the Sun on its eccentric 248-year orbit is contested: earlier work predicted it would, Olkin et al. (2015) found it does not collapse at any point in the orbit, and occultations from 2017 to 2023 suggest the pressure has started to drop, which their authors say needs more data to confirm.Olkin et al. 2015, IcarusSickafoose et al. 2026, Planetary Science Journal 7 (abstract)Planetary Science Institute release on Sickafoose et al.
Dark red regions such as Cthulhu are coloured by tholins — organic compounds made when ultraviolet light and charged particles act on nitrogen and methane.Stern et al. 2015, ScienceStern et al. 2018, ARA&ANASA JPL, PIA20477 Methane Snow on Pluto's Peaks
There are signs of an ocean of liquid water beneath its ice shell, perhaps kept from freezing by a thin insulating layer of gas hydrates, and possible ice volcanoes such as Wright Mons.NASA Science, Pluto factsNimmo et al. 2016, Nature 540, 94Stern et al. 2018, ARA&A
Its largest moon Charon is half its width — so large that the two orbit a point in the space between them, both turning to keep the same face toward each other.Porter & Canup 2023, Orbits and Masses of the Small Satellites of PlutoNASA Science, Pluto factsStern et al. 2018, ARA&A
Four tiny moons, Styx, Nix, Kerberos and Hydra, circle the pair.NASA Science, Pluto factsStern et al. 2018, ARA&APorter & Canup 2023, Orbits and Masses of the Small Satellites of Pluto
Pluto's orbit is tilted 17° and so stretched that for 20 years of every 248 it comes closer to the Sun than Neptune, as it did from 1979 to 1999; a 3:2 resonance with Neptune keeps the two from ever meeting.Malhotra & Ito 2022, Pluto near the edge of chaosNASA Science, Pluto factsNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)Stern et al. 2018, ARA&A
New Horizons, healthy and with fuel remaining, went on to fly past the small Kuiper belt object Arrokoth on 1 January 2019, the most distant world ever explored.NASA Science, ArrokothJHU APL New Horizons, 2019 Onward
mean radius · 1,188.3 kmNimmo et al. 2017, IcarusJPL SSD, planetary physical parametersStern et al. 2018, ARA&A
mean density · 1.854 g/cm³NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)Stern et al. 2018, ARA&A
surface gravity · 0.62 m/s²NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)Stern et al. 2018, ARA&A
escape velocity · 1.21 km/sNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
geometric albedo · ~0.5NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
sputnik planitia · ~1,300 × 900 km · nimmo et al. 2016; estimates differNimmo et al. 2016, Nature 540, 94McKinnon et al. 2016, Nature 534, 82
semi-major axis · 5,906 M km · 39.48 auNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbers
perihelion · aphelion · 29.66 · 49.3 au · perihelion 1989NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersJPL Small-Body Database, 134340 PlutoNASA Science, Pluto facts
eccentricity · 0.2488NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
inclination · 17.16°NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
sidereal period · 247.94 yrNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
rotation · 6.387 days, retrogradeNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersNASA Science, Pluto facts
axial tilt · 119.51° · to its orbitNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
resonance · 3 : 2 with neptuneStern et al. 2018, ARA&A
nitrogen · 99NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
methane · 0.5NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
carbon monoxide · 0.05NASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
surface pressure · ~11 µbar · new horizons, 2015Stern et al. 2018, ARA&AStern et al. 2015, ScienceNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
haze · layered, > 200 km up · blueStern et al. 2018, ARA&A
surface temperature · ~40 K · −233 °CNASA Science, Pluto facts; worked out from its numbersStern et al. 2018, ARA&ANASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
subsurface ocean · possible · nimmo et al. 2016, modelNimmo et al. 2016, Nature 540, 94Stern et al. 2018, ARA&A
rocky core · ~820–910 km radius · modelBagheri et al. 2021, The Tidal-Thermal Evolution of the Pluto-Charon SystemMcKinnon et al. 2020, Formation, Composition, and History of the Pluto System
internal field · none indicated: < 30 nT, inferred; no magnetometer aboardStern et al. 2018, ARA&A
charon · 1,212 km · half pluto's widthNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024); worked out from its numbersStern et al. 2018, ARA&ANASA Science, Pluto facts
hydra · ~52 × 37 kmPorter & Canup 2023, Orbits and Masses of the Small Satellites of PlutoStern et al. 2018, ARA&AWeaver et al. 2016, ScienceNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)
nix · ~48 × 34 kmPorter & Canup 2023, Orbits and Masses of the Small Satellites of PlutoNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)Stern et al. 2018, ARA&AWeaver et al. 2016, Science
kerberos · ~19 × 10 kmNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)Porter & Canup 2023, Orbits and Masses of the Small Satellites of PlutoStern et al. 2018, ARA&A
styx · ~16 × 9 kmWeaver et al. 2016, ScienceStern et al. 2018, ARA&A
1930 · clyde tombaugh · discovered itNASA NSSDCA, Pluto Fact Sheet (updated 11 Jan 2024)New Mexico State University Library, Clyde W. Tombaugh chronology
1978 · james christy · charon foundJHU APL New Horizons, Discovery of CharonStern et al. 2018, ARA&A
2006 · iau · named a dwarf planetIAU 2006 General Assembly, result of the resolution votesNASA Science, Pluto facts
2015 · new horizons · flyby, 14 julyStern et al. 2018, ARA&ANASA Science, Pluto facts
2019 · new horizons · on to arrokothNASA Science, Arrokoth
brightness now · mag ~14.6 · 8–10 inches of aperture or moreJPL Horizons, target 999, read 2026-11-01Sky & Telescope, See Pluto in 2015British Astronomical Association, Observer's Challenge 2021

The Orion Nebula5 traced

A glowing cloud of gas and dust where thousands of stars are being born, visible to the naked eye in Orion's sword.NASA Hubble release, Orion Nebula panorama, 2006NASA Night Sky Notes, A Flame in the Sky
It is the nearest large region of massive star birth known, about 1,300 light years away.Robberto et al. 2013, ApJSMenten et al. 2007, distance
It is lit by the Trapezium, a young cluster whose brightest star is about 38 times the Sun's mass.Max Planck Society, on Kraus et al. 2009Kraus et al. 2009
Hubble has imaged more than 150 dusty discs around its young stars, where planets may form.NASA, Panoramic Hubble Picture Surveys Star Birth, Proto-Planetary Systems in the Great Orion Nebula (1995)
Charles Messier added it to his catalogue in 1769.ESO, The Orion Nebula: the jewel in the sword

The Horsehead Nebula4 traced

A dark cloud of dust shaped like a horse's head, silhouetted against glowing red hydrogen.NASA Hubble, The Horsehead NebulaESO press release eso0202
It was first recorded on a photographic plate in 1888 by Williamina Fleming at Harvard.Harvard-Smithsonian CfA, Horsehead Nebula (IYA page)
The red glow behind it is hydrogen lit by the hot star Sigma Orionis.Pety et al. 2017, A&A (The anatomy of the Orion B Giant Molecular Cloud)
It is part of the Orion B molecular cloud, the same complex that holds the Flame Nebula.Pety et al. 2017, A&A (The anatomy of the Orion B Giant Molecular Cloud)

Messier 784 traced

A blue reflection nebula: dust in the Orion B cloud scattering the light of young stars.ESO press release eso1105Castellanos et al. 2011, M 78 reflection nebula (arXiv full text) (MNRAS, 441, 1137 (2011))Lee & Chen 2009, Triggered Star Formation on the Border of the Orion-Eridanus Superbubble (arXiv full text) (Astrophys.J.694:1423,2009)
It shines by starlight bouncing off dust, not by glowing gas of its own.NASA Hubble, Messier 78
Pierre Méchain discovered it in 1780.NASA Hubble, Messier 78
It is one of the brightest reflection nebulae in the sky, at about magnitude 8.ESO, eso1105NASA Hubble, Messier 78

Barnard's Loop5 traced

A huge, faint arc of glowing hydrogen that curves around Orion's belt and sword.NASA APOD 2017 April 6Foley et al. 2022, A 3D View of Orion: I. Barnard's LoopNASA APOD 2005 April 20
It is named for E. E. Barnard, who photographed it in 1894; W. H. Pickering had recorded it in 1889.Foley et al. 2022, A 3D View of Orion: I. Barnard's Loop
It is an arc about 14 degrees long, the width of about 28 full Moons.O'Dell et al. 2011, ApJFoley et al. 2022, A 3D View of Orion: I. Barnard's Loop
It is thought to be a bubble blown by supernovae and winds from Orion's massive stars.Foley et al. 2022, A 3D View of Orion: I. Barnard's Loop
Its distance is uncertain; studies usually place it near the Orion Nebula, about 1,300 to 1,400 light years away.O'Dell et al. 2011, ApJOchsendorf et al. 2015

The Flame Nebula4 traced

A glowing gas cloud beside Alnitak, the eastern star of Orion's belt, crossed by dark lanes of dust.NASA Photojournal, A Flame in Orion's BeltNASA APOD 2021 April 12
A hidden young star, IRS 2b, has been identified as the source that ionizes it.Bik et al. 2003, A&A 404, 249
Infrared images reveal hundreds of young stars hidden inside its dust.Skinner et al. 2003, ApJ (A Deep Chandra X-ray Observation of the Embedded Young Cluster in NGC 2024)
William Herschel discovered it in 1786.Steinicke, historical NGC/IC data

The Crab Nebula5 traced

The expanding wreck of a star whose explosion was seen from Earth in 1054.NASA Hubble Messier catalogue, Messier 1
Chinese astronomers recorded the supernova in 1054; it was visible in daylight for about 23 days.Green & Stephenson 2003, The Historical Supernovae
At its heart is the Crab pulsar, a neutron star spinning about 30 times a second.NASA Hubble, Messier 1
Its gas is still flying outward at over 1,000 km per second.NASA APOD, 2023 March 20, M1: The Expanding Crab Nebula
It is the first entry in Charles Messier's catalogue; he saw it in 1758.NASA Hubble lithograph, Multiwavelength Crab Nebula (M1)

The Veil Nebula4 traced

The shredded, glowing shell of a star that exploded thousands of years ago, also called the Cygnus Loop.NASA Hubble Caldwell catalogue, Caldwell 34NASA Hubble Caldwell catalogue, Caldwell 33
Estimates of when the supernova went off range from about 5,000 to 20,000 years ago.Harvard CfA, The Cygnus LoopFesen et al. 2018, MNRASESA/Hubble, heic0712b
The whole loop spans about 3 degrees of sky, six times the width of the full Moon.ESA/Hubble, heic0712b
William Herschel discovered it in 1784.Steinicke, historical NGC/IC data

The Vela Supernova Remnant4 traced

The vast, tangled cloud left by a star that exploded in Vela, with the Vela pulsar at its heart.ESO, The Vela supernova remnantNOIRLab, Vela Supernova Remnant (noirlab2406a)Bock et al. 1998, A high-resolution radio survey of the Vela supernova remnant (Astron.J. 116 (1998) 1886)
The star exploded about 11,000 years ago, judging by the age of its pulsar.Cha, Sembach & Danks 1999 (The Distance to the Vela Supernova Remnant), Table 2
It is one of the closest known supernova remnants, about 940 light years away.Araya et al. 2026, A&AChen et al. 2025
It spans about 8 degrees of sky, 16 times the width of the full Moon.Araya et al. 2026, A&A

Cassiopeia A5 traced

The expanding debris of a massive star whose explosion light reached Earth around 1680.Chandra, Historic SupernovasThorstensen et al. 2001, The Expansion Center and Dynamical Age of Cassiopeia ANASA APOD 2026 February 6
Its expansion dates the explosion, as seen from Earth, to about 1681, give or take 19 years.Fesen et al. 2006, ApJ (expansion asymmetry and age of Cas A)
No clear historical record of the supernova survives, perhaps because dust dimmed it.NASA, Vision of Stellar Ending
It is the brightest radio source in the sky beyond the Solar System at frequencies above 1 GHz.Li, Wang & Li 2026 (Particle Acceleration in Cassiopeia A)
The Chandra X-ray telescope spotted its central compact source, a neutron star, in its first-light image in 1999.Ho & Heinke 2009, Nature 462, 71Ho & Heinke 2009, the same paper free to read (arXiv)

Tycho's Supernova Remnant4 traced

The remains of a white dwarf star that blew itself apart, seen from Earth as a new star in 1572.Chandra, Historic SupernovasRuiz-Lapuente et al. 2004, The binary progenitor of Tycho Brahe's 1572 supernova, abstract
Tycho Brahe observed the supernova from November 1572; at its peak it rivalled Venus.Green & Stephenson 2003, The Historical SupernovaeSparavigna 2017
Light echoes from the blast confirmed in 2008 that it was a Type Ia supernova.Krause et al. 2008 (Tycho Brahe's 1572 supernova as a standard type Ia explosion)
It helped overturn the old idea that the starry heavens never change.Sparavigna 2017, Supernova 1572 and other newly observed stars in the literature of the time

Kepler's Supernova Remnant4 traced

The remains of the most recent supernova in our galaxy that people saw with the naked eye.NASA History, 420 Years Ago: Kepler Observes a Supernova
It was first noticed on 9 October 1604; Johannes Kepler studied it for a year.NASA History, 420 Years Ago: Astronomer Johannes Kepler Observes a Supernova
At its peak it outshone Jupiter.NASA History, 420 Years Ago: Astronomer Johannes Kepler Observes a Supernova
As of 2026 no later supernova in the Milky Way has been seen with the naked eye.Vink 2017, Supernova 1604, Kepler's supernova, and its remnant

SN 10064 traced

The remnant of probably the brightest supernova in recorded history, seen in the year 1006.NASA APOD 2013 April 23Chandra, SN 1006, 2008
Observers in China, Japan, Egypt, Iraq and Europe recorded it in 1006.Winkler, Gupta & Long 2003, ApJ (The SN 1006 Remnant)
Its peak brightness is estimated at about magnitude −7.5, far brighter than Venus.Winkler, Gupta & Long 2003, ApJ (The SN 1006 Remnant)
It is generally taken to have been a Type Ia supernova, the explosion of a white dwarf.Chandra X-ray Center, SN 1006Winkler, Gupta & Long 2003, ApJ

Supernova 1987A5 traced

A star that exploded in the Large Magellanic Cloud, seen from Earth in February 1987.NASA Hubble, Supernova 1987A in the Large Magellanic Cloud
First seen on 24 February 1987, it was the closest observed supernova since Kepler's in 1604.Barlow 2025Chandra X-ray Center, SN 1987A
About two dozen neutrinos from the blast were detected on Earth hours before its light arrived.Raffelt, Janka & Fiorillo 2025Dar 1997, timing
Its light left the star about 168,000 years before it reached us.NASA Hubble, Supernova 1987A in the Large Magellanic Cloud (citing Panagia 1999)
In 2024 JWST found evidence of a neutron star hidden in its debris.Fransson et al. 2024, ScienceFransson et al. 2024, the same paper free to read (arXiv)NASA's release, 22 Feb 2024

The Ring Nebula4 traced

A glowing ring of gas cast off by a dying Sun-like star, with a hot white dwarf at its centre.NASA Hubble release, the Ring Nebula's true shapeNASA Hubble Messier catalogue, Messier 57
Charles Messier found it on 31 January 1779; Antoine Darquier, long given the credit, saw it the following month.Steinicke, historical NGC/IC data
The ring is roughly one light year across.NASA APOD, 2021 August 17, M57: The Ring Nebula from Hubble
The Sun is expected to shed a nebula like this in about 5 billion years.NASA, Helix Nebula image article

The Dumbbell Nebula3 traced

A bright planetary nebula, the gas shell of a dying star, shaped like an apple core or dumbbell.NOIRLab, M27: The Dumbbell NebulaNASA Hubble Messier catalogue, Messier 27
It was the first planetary nebula ever discovered, by Charles Messier in 1764.NASA Hubble, Messier 27
At magnitude 7.5 it is bright enough to see in binoculars.NASA Hubble, Messier 27NASA APOD, 2011 Dec 27

The Helix Nebula5 traced

One of the nearest planetary nebulae, the glowing outer layers of a dying star, sometimes called the Eye of God.NASA Hubble Caldwell catalogue, Caldwell 63ESO, The Helix Nebula
At about 650 light years it is one of the nearest known planetary nebulae to Earth.NASA Hubble, Caldwell 63
Its bright rings appear nearly half the width of the full Moon; fainter structures reach about 25 arcminutes.NASA Hubble, Caldwell 63Meaburn et al. 2013
It holds thousands of comet-shaped gas knots, each with a head wider than our Solar System.NASA, Hubble Finds Thousands of Gaseous Fragments Surrounding a Dying Star (1996)
Karl Ludwig Harding discovered it before 1824.NASA Hubble, Caldwell 63

The Cat's Eye Nebula4 traced

An intricate planetary nebula of shells and jets around a dying star, near the north pole of the ecliptic.NASA Hubble Caldwell catalogue, Caldwell 6ESA, The Cat's Eye Nebula, 2015
In 1864 William Huggins took its spectrum, the first of a planetary nebula, proving such objects are gas.Zijlstra 2015, RMxAANASA Hubble, Caldwell 6
Hubble images show at least eleven rings, puffs of gas shed roughly every 1,500 years.ESA/Hubble, heic0414
William Herschel discovered it in 1786.NASA Hubble, Caldwell 6

The Owl Nebula3 traced

A round planetary nebula toward the bottom of the Big Dipper's bowl, with two dark patches that look like an owl's eyes.NASA APOD 2009 May 15NOIRLab, Why the Owl Nebula Looks Like an Owl
Pierre Méchain discovered it in 1781.The Owl Nebula - M97, Observers' Forum, J. Br. Astron. Assoc. 121, 2 (2011), p. 114
In 1848 observers using Lord Rosse's great telescope at Birr Castle made out its owl shape.The Owl Nebula - M97, J. Br. Astron. Assoc. 121, 2 (2011), p. 114

The Southern Ring Nebula4 traced

A planetary nebula of gas shells around a dying star in a binary, imaged in detail by JWST.NASA Hubble Caldwell catalogue, Caldwell 74NASA Webb release, 12 July 2022
It was one of the first images released by the James Webb Space Telescope, in July 2022.ESA/Webb, Webb's First ImagesNASA, Webb's First Images
Webb gave the clearest view yet of the star that made the nebula, the fainter of the two at its centre.ESA/Webb, weic2207
John Herschel discovered it in 1835.NASA Hubble Caldwell Catalog, Caldwell 74

The Eagle Nebula4 traced

A star-forming cloud and young cluster, home of the dust columns called the Pillars of Creation.NASA Hubble Messier catalogue, Messier 16
Hubble photographed its Pillars of Creation in 1995, one of its most famous images.ESA, The most famous astronomical image of the 20th centuryNASA Hubble Messier Catalog, Messier 16
The tallest pillar is about 4 light years long.ESA, The most famous astronomical image of the 20th centuryNASA Hubble Messier Catalog, Messier 16
Its star cluster was discovered by Philippe Loys de Chéseaux around 1745.NASA Hubble Messier Catalog, Messier 16Steinicke, historical NGC/IC data

The Lagoon Nebula4 traced

A large glowing cloud of star birth in Sagittarius, visible to the naked eye from dark sites.NASA Hubble Messier catalogue, Messier 8
It spans about 45 by 30 arcminutes, about one and a half full Moons wide.Steinicke, historical NGC/IC data
It holds the young star cluster NGC 6530, only a few million years old.Tothill et al. 2008, Handbook of Star Forming Regions IINASA Hubble Messier Catalog, Messier 8
Giovanni Hodierna recorded it in 1654.NASA Hubble Messier Catalog, Messier 8

The Trifid Nebula3 traced

A star-forming nebula split into three lobes by dark dust lanes, with a blue reflection nebula beside it.NASA APOD 2011 May 13NASA Hubble Messier catalogue, Messier 20
It combines three kinds of nebula: red glowing gas, blue reflecting dust and dark dust lanes.ESO press release eso0930
Charles Messier discovered it in 1764; John Herschel later named it the Trifid.ESO press release eso0930NASA Hubble Messier Catalog, Messier 20

The Omega Nebula3 traced

A bright region of star birth, also called the Swan Nebula, lit by a cluster of hot young stars.NASA Hubble Messier catalogue, Messier 17
It is the second-brightest glowing gas region in our sky after Orion, and one of the largest star-forming regions in the Milky Way.Townsley et al. 2006, An X-ray Tour of Massive Star-forming RegionsLim et al. 2020, SOFIA survey of giant H II regions II: M17NASA Hubble Messier Catalog, Messier 17
Philippe Loys de Chéseaux discovered it in 1745; Messier catalogued it in 1764.NASA Hubble Messier Catalog, Messier 17Steinicke, historical NGC/IC data

The Carina Nebula4 traced

One of the largest and brightest nebulae in the sky, a vast star-forming region around Eta Carinae.ESO, The Carina NebulaNASA Hubble Caldwell catalogue, Caldwell 92
It is about four times larger than the Orion Nebula and far brighter.ESO image b08, The Carina Nebula
It holds Eta Carinae and several of the most massive stars known in our galaxy.Smith & Brooks 2008, The Carina Nebula: A Laboratory for FeedbackESO image b08, The Carina NebulaNASA Hubble Caldwell Catalog, Caldwell 92
Nicolas-Louis de Lacaille discovered it in 1752 from the Cape of Good Hope.NASA Hubble Caldwell Catalog, Caldwell 92

The Rosette Nebula4 traced

A rose-shaped cloud of glowing gas whose central cluster has hollowed out its middle.NASA APOD 2015 February 25Wareing et al. 2018, A new mechanical stellar wind feedback model for the Rosette Nebula (MNRAS, Volume 475, Issue 3, Pages 3598-3612, 2018)
Its central cluster, NGC 2244, has blown a hole through the middle with its stellar winds.NOIRLab noirlab2424, Radiant Stars at the Heart of a Cosmic RoseESO image b12, The Rosette NebulaNASA APOD 2005 Feb 14, The Rosette Nebula
It spans about 1.3 degrees of sky, more than twice the width of the full Moon.NOIRLab noirlab2424, Radiant Stars at the Heart of a Cosmic Rose
John Flamsteed noticed its star cluster around 1690.ESO image b12, The Rosette Nebula

The North America Nebula4 traced

A large glowing cloud of hydrogen whose outline resembles the continent of North America.NASA Hubble Caldwell catalogue, Caldwell 20
A dark dust lane forms its 'Gulf of Mexico'.Spitzer/Caltech ssc2011-03b, North America Nebula DisappearsRebull et al. 2011, The North American and Pelican Nebulae II
It spans about 2 degrees of sky, four times the width of the full Moon.Steinicke, historical NGC/IC data
William Herschel discovered it in 1786.NASA Hubble Caldwell Catalog, Caldwell 20

The California Nebula4 traced

A long glowing cloud of hydrogen in Perseus shaped like the state of California.NASA APOD 2019 August 23
E. E. Barnard discovered it in 1885.Steinicke, historical NGC/IC data
It is most likely lit by the hot blue star Xi Persei.NASA APOD 2019 Aug 23, NGC 1499: The California Nebula
It is about 2 degrees long, four times the width of the full Moon, but very faint.Steinicke, historical NGC/IC data

The Rho Ophiuchi Cloud3 traced

A nearby complex of dust clouds where hundreds of stars are forming.ESA, Rho Ophiuchi cloud complex (Herschel and Planck)Wilking et al. 2008, Star Formation in the Rho Ophiuchi Molecular Cloud, abstract
It is one of the closest star-forming regions to the Sun, about 450 light years away.Wilking et al. 2008, Handbook of Star Forming Regions IIOrtiz-León et al. 2017, ApJ
Its dense core hides over 300 young stars, some so obscured that they show only at longer infrared wavelengths.Wilking et al. 2008, Handbook of Star Forming Regions II

The Coalsack4 traced

A dark cloud of dust beside the Southern Cross that blots out the Milky Way behind it.NASA Hubble Caldwell catalogue, Caldwell 99
It is one of the most prominent dark nebulae visible to the naked eye.ESO image b06, The Coalsack and the Southern CrossESO press release eso1539Beuther et al. 2011, The Coalsack near and far
It spans about 6 degrees of sky, and may extend up to 10.Coalsack extinction study 2025, arXiv:2502.08956
In Aboriginal Australian astronomy it forms the head of the Emu in the Sky.Norris 2016, PASANorris 2016, the same paper free to read (arXiv)ESO Picture of the Week potw2112a, Coalsack, Emu, Tinamou?

The Iris Nebula3 traced

A blue reflection nebula, a dust cloud lit like a flower by the young star at its centre.NASA Hubble Caldwell catalogue, Caldwell 4Sharma et al. 2025, Imprints of Stellar Feedback in the Iris Nebula NGC 7023
Its blue colour is starlight scattered by dust, a similar effect to the one that makes Earth's sky blue.NASA Hubble Caldwell Catalog, Caldwell 4NASA Image of the Day, Witch Head Nebula (general process)
William Herschel discovered it in 1794.NASA Hubble Caldwell Catalog, Caldwell 4

The Witch Head Nebula4 traced

A blue reflection nebula shaped like a witch's profile, lit by the bright star Rigel.NASA, Witch Head NebulaNASA APOD 2012 January 17
It is lit by Rigel, the brilliant blue supergiant at the foot of Orion.NASA APOD 2018 Jan 15, Rigel and the Witch Head NebulaNASA APOD 2023 Apr 7, Rigel Wide
It stretches about 3 to 5 degrees across the sky and is too faint to see with the unaided eye.Guieu et al. 2010, Spitzer Observations of IC 2118The Planetary Society, The Witch Head Nebula
Dust scatters blue light more than red, which gives it its colour.NASA APOD 2018 Jan 15, Rigel and the Witch Head NebulaNASA APOD 2023 Oct 4, IC 2118: The Witch Head Nebula

The Tarantula Nebula4 traced

A giant star-forming region in the Large Magellanic Cloud, the most active one known in our Local Group.NASA APOD 2007 August 22ESA, The Tarantula NebulaTownsley et al. 2024, The Tarantula, Revealed by X-rays (T-ReX)
It is the most active star-forming region known in the Local Group of galaxies.NASA, Hubble's Close Encounter with the Tarantula
Its central cluster R136 holds R136a1, among the most massive stars known, with estimates from about 150 to 265 Suns.Kalari et al. 2022, ApJKalari et al. 2022, the same paper free to read (arXiv)Bestenlehner et al. 2020, MNRASBestenlehner et al. 2020, the same paper free to read (arXiv)Crowther et al. 2010, MNRASCrowther et al. 2010, the same paper free to read (arXiv)
Nicolas-Louis de Lacaille recorded it in 1751.NASA Hubble Caldwell Catalog, Caldwell 103

The Pleiades5 traced

A bright young star cluster in Taurus, easily seen with the naked eye as a tiny dipper of stars.NASA Hubble Messier catalogue, Messier 45NOIRLab, Constellation: Taurus
It is about 125 million years old, young next to the Sun's 4.6 billion years.Stauffer et al. 1998, ApJStauffer et al. 1998, the same paper free to read (arXiv)NASA, Sun facts
Galileo counted 36 stars in it through his telescope in 1610.Galileo, The Sidereal Messenger (Carlos translation, 1880)
Its blue haze is a dust cloud the cluster happens to be passing through.NASA/STScI, Ghostly Reflections in the Pleiades
Hipparcos measured it closer than other methods did; radio VLBI, then Gaia, put it at about 444 ly.Melis et al. 2014, ScienceGaia Collaboration, Babusiaux et al. 2018, A&AGaia Collaboration, van Leeuwen et al. 2017, A&A

The Hyades4 traced

The nearest known open star cluster, a V-shaped group forming the face of Taurus the Bull.ESA Gaia, Is the nearest star cluster to the Sun being destroyed?NOIRLab, Constellation: Taurus
At about 153 light years, it is usually counted as the nearest open cluster to the Sun.Gaia Collaboration, van Leeuwen et al. 2017, A&ANASA APOD 2022 Dec 30, Mars and the Star ClustersPerryman et al. 1998, A&A
It is about 625 million years old.Perryman et al. 1998, A&A
Bright Aldebaran sits in front of it but is not a member; it is less than half as far.NASA APOD 2022 Dec 30, Mars and the Star Clusters

The Beehive Cluster4 traced

An open cluster of about 1,000 stars in Cancer, seen as a blur of light by the naked eye.NASA Hubble Messier catalogue, Messier 44
Galileo resolved it into more than 40 stars in 1610.Galileo, The Sidereal Messenger (Carlos translation, 1880)NASA Hubble Messier Catalog, Messier 44
It is about 600 to 700 million years old, similar to the Hyades.NASA Hubble Messier Catalog, Messier 44Gaia Collaboration, Babusiaux et al. 2018, A&A
Planets have been found orbiting some of its stars.Quinn et al. 2012, ApJLQuinn et al. 2012, the same paper free to read (arXiv)

The Double Cluster4 traced

Two young star clusters side by side in Perseus, both visible to the naked eye.NASA Hubble Caldwell catalogue, Caldwell 14
Its two clusters, NGC 869 and NGC 884, lie about 7,460 and 7,640 light years away.Currie et al. 2010, ApJSCurrie et al. 2010, the same paper free to read (arXiv)NASA Hubble Caldwell Catalog, Caldwell 14
Both are only about 14 million years old.Currie et al. 2010, ApJSCurrie et al. 2010, the same paper free to read (arXiv)
Hipparchus noted it around 130 BC.NASA APOD 2007 Dec 7, Double Cluster in Perseus

The Great Hercules Cluster5 traced

A ball of hundreds of thousands of ancient stars, one of the brightest globular clusters in the northern sky.NASA Hubble Messier catalogue, Messier 13NASA Hubble Messier catalogue, Messier 22
Its mass is about 480,000 times the Sun's.Baumgardt, Galactic globular cluster databaseBaumgardt & Hilker 2018, MNRASBaumgardt & Hilker 2018, the same paper free to read (arXiv)
It is roughly 12 billion years old.Forbes & Bridges 2010, MNRASVandenBerg et al. 2013, ApJ
The 1974 Arecibo radio message was aimed at it; it will take about 25,000 years to arrive.Cornell Chronicle 1999, 25th anniversary of first attempt to phone E.T.NASA Hubble Messier Catalog, Messier 13
Edmond Halley discovered it in 1714.NASA Hubble Messier Catalog, Messier 13

Omega Centauri5 traced

The largest globular cluster in our galaxy, holding millions of stars, possibly a dwarf galaxy stripped of its outer stars.NASA Hubble Caldwell catalogue, Caldwell 80
Its mass is about 3.9 million times the Sun's, the most of any known Milky Way globular.Baumgardt, Galactic globular cluster databaseBaumgardt & Hilker 2018, MNRASBaumgardt & Hilker 2018, the same paper free to read (arXiv)NASA Hubble Caldwell Catalog, Caldwell 80
Ptolemy listed it as a star; Edmond Halley saw it was a nebula in 1677.NASA Hubble Caldwell Catalog, Caldwell 80
In 2024 Hubble data revealed a black hole of at least 8,200 solar masses near its centre.Häberle et al. 2024, NatureHäberle et al. 2024, the same paper free to read (arXiv)
Many astronomers think it is the core of a small galaxy the Milky Way absorbed.NASA Hubble Caldwell Catalog, Caldwell 80Bekki & Freeman 2003, MNRAS

47 Tucanae5 traced

A brilliant globular cluster in the southern sky, second only to Omega Centauri in brightness.NASA Hubble Caldwell catalogue, Caldwell 106
Its mass is about 850,000 times the Sun's.Baumgardt, Galactic globular cluster databaseBaumgardt & Hilker 2018, MNRASBaumgardt & Hilker 2018, the same paper free to read (arXiv)
It hosts more than 20 millisecond pulsars.Ridolfi et al. 2016, MNRAS
It appears beside the Small Magellanic Cloud but is nearly 14 times closer.Graczyk et al. 2020, ApJBaumgardt & Vasiliev 2021, MNRASNASA Hubble Caldwell Catalog, Caldwell 106
Nicolas-Louis de Lacaille catalogued it in 1751.NASA Hubble's Caldwell Catalog: Caldwell 106

Ptolemy's Cluster4 traced

A bright open cluster near the sting of Scorpius, easy to see with the naked eye.NASA Hubble Messier catalogue, Messier 7
Ptolemy recorded it around 130 AD.NASA Hubble's Messier Catalog: Messier 7NOIRLab, M7, NGC 6475
It is about 200 million years old.Villanova et al. 2009, A&A (NGC 6475 spectroscopic study)Sestito et al. 2003, A&A (lithium in NGC 6475)Sestito et al. 2003, the same paper free to read (arXiv)NASA Hubble's Messier Catalog: Messier 7
At magnitude 3.3 it is an easy naked-eye target.NASA Hubble's Messier Catalog: Messier 7

The Butterfly Cluster3 traced

An open cluster in Scorpius whose outline suggests the shape of a butterfly.NASA APOD 2025 July 19NASA APOD 2014 September 3
Estimates of its age run from about 50 to 100 million years.NOIRLab, M6, NGC 6405; Butterfly ClusterKılıçoğlu et al. 2016, AJ 151, 49Kılıçoğlu et al. 2016, the same paper free to read (arXiv)
Its most conspicuous star, the variable BM Scorpii, is an orange K-type supergiant.Wittkowski et al. 2017, A&A (VLTI/AMBER late-type supergiants)Wittkowski et al. 2017, the same paper free to read (arXiv)Kılıçoğlu et al. 2016, AJ 151, 49Kılıçoğlu et al. 2016, the same paper free to read (arXiv)NOIRLab, M6, NGC 6405; Butterfly Cluster

The Wild Duck Cluster4 traced

One of the richest and most compact open clusters in the night sky, in the constellation Scutum.NASA Hubble Messier catalogue, Messier 11
Its V-shaped pattern of bright stars reminded observers of a flight of wild ducks.NASA Hubble's Messier Catalog: Messier 11
Estimates of its age run from about 220 to 316 million years.Cantat-Gaudin et al. 2014, A&A (Gaia-ESO, NGC 6705)Cantat-Gaudin et al. 2014, the same paper free to read (arXiv)Casamiquela et al. 2018, A&A 610, A66 (NGC 6705 from OCCASO data)Casamiquela et al. 2018, the same paper free to read (arXiv)NASA Hubble's Messier Catalog: Messier 11
Gottfried Kirch discovered it in 1681.NASA Hubble's Messier Catalog: Messier 11

Messier 224 traced

A bright globular cluster in Sagittarius, one of the nearest to Earth.NASA Hubble Messier catalogue, Messier 22
It was one of the first globular clusters discovered, by Abraham Ihle in 1665.NASA Hubble's Messier Catalog: Messier 22
In 2012 radio astronomers found two stellar-mass black holes inside it.Strader et al. 2012, NatureStrader et al. 2012, the same paper free to read (arXiv)NASA Hubble's Messier Catalog: Messier 22
Its mass is about 470,000 times the Sun's.Baumgardt, Galactic globular cluster databaseBaumgardt & Hilker 2018, MNRAS (catalogue table)Baumgardt & Hilker 2018, the same paper free to read (arXiv)

Messier 45 traced

One of the closest globular clusters to the Sun, a ball of old stars near Antares.NASA Hubble Messier catalogue, Messier 4
At about 6,000 light years, it is among the closest globular clusters to the Sun.Baumgardt & Vasiliev 2021, MNRASBaumgardt & Vasiliev 2021, the same paper free to read (arXiv)NASA Hubble's Messier Catalog: Messier 4
Hubble dated its oldest white dwarfs to about 12 billion years.Hansen et al. 2002, ApJ 574, L155Hansen et al. 2002, the same paper free to read (arXiv)
A planet of about 2.5 Jupiter masses orbits a pulsar and white dwarf pair inside it.Sigurdsson et al. 2003, Science 301, 193Sigurdsson et al. 2003, the same paper free to read (arXiv)
Philippe Loys de Chéseaux discovered it in 1746.NASA Hubble's Messier Catalog: Messier 4

Messier 34 traced

A large, bright globular cluster of about half a million stars, rich in variable stars.NASA Hubble Messier catalogue, Messier 3
It was Charles Messier's first original discovery, in 1764.NASA Hubble's Messier Catalog: Messier 3
At least 274 variable stars have been found in it.NASA Hubble's Messier Catalog: Messier 3
Its mass is about 410,000 times the Sun's.Baumgardt, Galactic globular cluster databaseBaumgardt & Hilker 2018, MNRAS (catalogue table)Baumgardt & Hilker 2018, the same paper free to read (arXiv)

Messier 154 traced

One of the densest globular clusters known, with a collapsed core packed with stars.NASA Hubble Messier catalogue, Messier 15Gerssen et al. 2002, Evidence for an Intermediate-Mass Black Hole in M15: II (arXiv full text)
Pease 1, found in it in 1928, was the first planetary nebula known inside a globular cluster.NASA Hubble's Messier Catalog: Messier 15
Jean-Dominique Maraldi discovered it in 1746.NASA Hubble's Messier Catalog: Messier 15
Its mass is about 520,000 times the Sun's.Baumgardt, Galactic globular cluster databaseBaumgardt & Hilker 2018, MNRAS (catalogue table)Baumgardt & Hilker 2018, the same paper free to read (arXiv)

The Coma Star Cluster4 traced

A sparse open cluster of stars in the constellation Coma Berenices.Agüeros et al. 2025, Crowning the Queen: the Open Cluster Coma Berenices (ApJ 993 144 (2025))Silaj & Landstreet 2014, Accurate age determinations of several nearby open clusters (arXiv full text)
Its stars spread over roughly 8 degrees of sky.Casewell et al. 2006, MNRAS 365, 447Casewell et al. 2006, the same paper free to read (arXiv)
It is one of the nearest open clusters to the Sun.Casewell et al. 2006, MNRAS 365, 447Casewell et al. 2006, the same paper free to read (arXiv)A massive white dwarf member of the Coma Berenices Open Cluster, MNRAS 2009Dobbie et al. 2009, the same paper free to read (arXiv)
The name Coma Berenices means Berenice's Hair, after Queen Berenice II of Egypt.NOIRLab, Constellation: Coma BerenicesBiviano, Our Best Friend, the Coma Cluster (NED)

The Southern Pleiades3 traced

A bright young open cluster in Carina, around the star Theta Carinae.NOIRLab, Constellation: CarinaBouma et al. 2020, TOI 837: A Young Validated Planet in IC 2602 (arXiv full text)
Its brightest star is Theta Carinae, a hot blue star.Bouma et al. 2020, AJ (CDIPS II, TOI 837)Bouma et al. 2020, the same paper free to read (arXiv)Walborn 1979, PASP, the chemically peculiar B star Theta Carinae
Nicolas-Louis de Lacaille discovered it in 1751.Steinicke, historical NGC/IC data

Messier 354 traced

A large open cluster near the feet of Gemini, visible in binoculars.NASA Hubble Messier catalogue, Messier 35
It is about 150 million years old.NASA Hubble's Messier Catalog: Messier 35Meibom et al. 2009, ApJ 695, 679Meibom et al. 2009, the same paper free to read (arXiv)
Beside it in the sky lies the older, much more distant cluster NGC 2158.NASA APOD 2021 May 10, Star Clusters M35 and NGC 2158NASA Hubble's Messier Catalog: Messier 35
Philippe Loys de Chéseaux discovered it in 1745.NASA Hubble's Messier Catalog: Messier 35

The Jewel Box4 traced

A young open cluster in the Southern Cross with a mix of blue supergiants and one red supergiant.ESO press release eso0940NASA Hubble Caldwell catalogue, Caldwell 94
John Herschel named it in the 1830s for its mix of coloured stars.ESO press release eso0940
It is only about 16 million years old.NASA Hubble's Caldwell Catalog: Caldwell 94
Nicolas-Louis de Lacaille discovered it in 1752.NASA Hubble's Caldwell Catalog: Caldwell 94

The Andromeda Galaxy5 traced

The nearest large spiral galaxy to the Milky Way, holding roughly a trillion stars.NASA Hubble Messier catalogue, Messier 31NASA APOD 2007 July 21NASA Photojournal, Andromeda Galaxy
It is the most distant object easily visible to the unaided eye.NASA APOD 2023 March 22, M31: The Andromeda Galaxy
Edwin Hubble found a Cepheid in it in 1923 and announced in 1925 that it lies far outside our galaxy.Elizalde 2018, Galaxies 6, 25Elizalde 2018, the same paper free to read (arXiv)Carnegie Science, Hubble's Famous M31 VAR! plateNASA, Hubble Views the Star That Changed the Universe
It is approaching the Milky Way at about 110 km per second.van der Marel et al. 2012, ApJ 753, 8van der Marel et al. 2012, the same paper free to read (arXiv)
Its light left it about 2.5 million years ago.NASA Hubble's Messier Catalog: Messier 31

The Triangulum Galaxy3 traced

A spiral galaxy in the Local Group, the third largest after Andromeda and the Milky Way.NASA Hubble Messier catalogue, Messier 33
Under very dark skies it is at the limit of naked-eye visibility.NASA Hubble's Messier Catalog: Messier 33
Published distances to it run from about 730 to 960 kpc. Here it stands 790.5 kpc from the Sun, placed by McConnachie et al. 2005 (809 kpc, with Andromeda at 785 kpc in the same table), so it and Andromeda keep their measured places against each other.McConnachie et al. 2005McConnachie et al. 2005, the same paper free to read (arXiv)Brunthaler et al. 2005, Science (masers)Brunthaler et al. 2005, the same paper free to read (arXiv)Bonanos et al. 2006, ApJ (eclipsing binary)Bonanos et al. 2006, the same paper free to read (arXiv)Breuval et al. 2023, ApJ (Cepheids)Breuval et al. 2023, the same paper free to read (arXiv)

The Large Magellanic Cloud4 traced

A dwarf satellite galaxy of the Milky Way, seen from the southern hemisphere as a fuzzy, cloud-like patch.NASA APOD 2023 September 7ESO, Magellanic Clouds, irregular dwarf galaxiesNASA Hubble, Aftermath of Galaxy's Scrape with Milky Way
The Persian astronomer al-Sufi's book of about 964 holds what is thought to be its earliest mention.ESO, Magellanic Clouds, irregular dwarf galaxiesDennefeld 2020, A History of the Magellanic Clouds (arXiv)
It hosts the Tarantula Nebula and the supernova SN 1987A.NASA Hubble's Caldwell Catalog: Caldwell 103ESO, Magellanic Clouds, irregular dwarf galaxies
Its distance was measured to about 1% using eclipsing binary stars in 2019.Pietrzyński et al. 2019, NaturePietrzyński et al. 2019, the same paper free to read (arXiv)

The Small Magellanic Cloud4 traced

A dwarf satellite galaxy of the Milky Way, visible to the naked eye in the far southern sky.ESA, Exploring the colours of the Small Magellanic CloudESO, Magellanic Clouds, irregular dwarf galaxies
It contains hundreds of millions of stars.ESA, Head in the clouds (2022)
Henrietta Leavitt found the Cepheid period–luminosity law from its stars, published in 1912.Breuval et al. 2025, PASPBreuval et al. 2025, the same paper free to read (arXiv)
Those stars became the first known standard candles for measuring distances to other galaxies.Breuval et al. 2025, PASPPerivolaropoulos 2024 (arXiv)Polzin et al. 2023 (arXiv)

Bode's Galaxy4 traced

A bright grand-design spiral galaxy in Ursa Major, paired with the Cigar Galaxy.NASA Hubble Messier catalogue, Messier 81NASA Hubble release, Grand Design Spiral Galaxy M81
Johann Elert Bode discovered it in 1774.NASA Hubble's Messier Catalog: Messier 81ESA, The spiral galaxy M81 in Ursa Major
Its gravity has stirred up its neighbour M82, triggering a burst of star formation.NASA Hubble's Messier Catalog: Messier 82
Its central black hole is about 70 million times the Sun's mass.NASA Hubble's Messier Catalog: Messier 81

The Cigar Galaxy4 traced

A starburst galaxy, forming stars rapidly because of gravitational interactions with its neighbour M81.NASA Hubble Messier catalogue, Messier 82
Its centre forms stars about ten times faster than the whole Milky Way.NASA Hubble's Messier Catalog: Messier 82
Winds from its young stars blast gas thousands of light years out of its disc.Center for Astrophysics, Harvard & Smithsonian: magnetic field in M82's outflowNASA Hubble's Messier Catalog: Messier 82
In 2014 it hosted SN 2014J, the nearest Type Ia supernova seen in decades.Goobar et al. 2014, ApJL 784, L12Goobar et al. 2014, the same paper free to read (arXiv)

The Whirlpool Galaxy4 traced

A classic face-on spiral galaxy interacting with a small companion galaxy, NGC 5195.NASA Hubble Messier catalogue, Messier 51
Lord Rosse saw and drew its spiral arms in 1845, the first spiral nebula recognised.Steinicke 2012, JAHH 15, 19
Its spiral arms are shaped by the pull of its companion, NGC 5195.Dobbs et al. 2010, MNRASDobbs et al. 2010, the same paper free to read (arXiv)NASA Hubble's Messier Catalog: Messier 51
Charles Messier discovered it in 1773.NASA Hubble's Messier Catalog: Messier 51

The Sombrero Galaxy4 traced

A galaxy with a bright bulge and a dark dust lane, resembling a broad-brimmed hat.NASA Hubble Messier catalogue, Messier 104
Its central black hole is about 660 million times the Sun's mass.Jardel et al. 2011, ApJ 739, 21Jardel et al. 2011, the same paper free to read (arXiv)
Pierre Méchain discovered it in 1781.NASA Hubble's Messier Catalog: Messier 104
Vesto Slipher measured it receding at about 1,000 km per second in 1912–13, an early clue to cosmic expansion.ESO, Sombrero galaxy image eso0007aO'Raifeartaigh 2012, The contribution of VM Slipher to the discovery of the expanding universe (arXiv) (Origins of the Expanding Universe 1912-1923 ASP Conf. Ser. 471 pp 49-63)

Messier 874 traced

A giant elliptical galaxy near the centre of the Virgo Cluster, with a jet powered by its black hole.Chandra, M87, 2008NASA Hubble Messier catalogue, Messier 87
Its jet of particles stretches at least 5,000 light years from the core.NASA, Galaxy M87 Jet (Annotated)
It holds roughly 14,000 to 15,000 globular clusters, against about 150 to 160 for the Milky Way.NASA Hubble's Messier Catalog: Messier 87Harris 2009, ApJ 703, 939Harris 2009, the same paper free to read (arXiv)Madrid et al. 2009, ApJ 705, 237Madrid et al. 2009, the same paper free to read (arXiv)Baumgardt & Vasiliev 2021, MNRASBaumgardt & Vasiliev 2021, the same paper free to read (arXiv)
Its central black hole was the first ever imaged, in 2019.ESO press release eso1907

Centaurus A5 traced

A nearby galaxy crossed by a dark dust lane, with giant radio lobes powered by its central black hole.NASA Hubble Caldwell catalogue, Caldwell 77Chandra, Centaurus A, 2009Stawarz et al. 2012, Giant Lobes of Centaurus A with Suzaku
Its radio lobes span about 10 degrees of sky, 20 times the full Moon's width.Fermi-LAT Collaboration 2010, Fermi Gamma-ray Imaging of a Radio Galaxy (arXiv)
Its central black hole is about 45 to 55 million times the Sun's mass.Cappellari et al. 2009, MNRAS 394, 660Neumayer et al. 2007, The Central Parsecs of Centaurus A (arXiv)
Its dust lane is thought to come from merging with a smaller spiral galaxy.ESO press release eso0944Israel 1998, A&A Review 8, 237Israel 1998, the same paper free to read (arXiv)
James Dunlop discovered it in 1826.NASA Hubble Caldwell catalog: Caldwell 77

The Pinwheel Galaxy3 traced

A large face-on spiral galaxy in Ursa Major, with lopsided arms full of star-forming regions.NASA Hubble Messier catalogue, Messier 101NASA SVS, M101
In 2011 it hosted SN 2011fe, one of the closest Type Ia supernovae seen in decades.Nugent et al. 2011, Nature 480, 344Nugent et al. 2011, the same paper free to read (arXiv)
Pierre Méchain discovered it in 1781.NASA Hubble Messier catalog: Messier 101

Sagittarius A*5 traced

The supermassive black hole at the centre of the Milky Way.ESO press release eso2208
It is about 4.3 million times the Sun's mass, measured from stars orbiting it.GRAVITY Collaboration 2022, A&A 657, L12GRAVITY Collaboration 2022, the same paper free to read (arXiv)
The star S2 circles it about every 16 years.GRAVITY Collaboration 2018, A&A 615, L15GRAVITY Collaboration 2018, the same paper free to read (arXiv)
Andrea Ghez and Reinhard Genzel shared half of the 2020 Nobel Prize in Physics for discovering a supermassive compact object at the centre of our galaxy.Nobel Prize in Physics 2020, press release
The Event Horizon Telescope released the first image of its shadow in May 2022.ESO press release eso2208-eht-mw, 12 May 2022EHT Collaboration 2022, ApJL 930, L12EHT Collaboration 2022, the same paper free to read (arXiv)

Gaia BH13 traced

A dormant black hole orbited by a Sun-like star, the nearest known black hole to Earth.El-Badry et al. 2022, A Sun-like star orbiting a black hole
It is the nearest known black hole to Earth, as of 2024.El-Badry et al. 2023, MNRAS 518, 1057El-Badry et al. 2023, the same paper free to read (arXiv)ESO press release eso2408, 16 April 2024
Kareem El-Badry and colleagues found it in 2022 from the wobble of its star in Gaia data.El-Badry et al. 2023, MNRAS 518, 1057El-Badry et al. 2023, the same paper free to read (arXiv)

Gaia BH23 traced

A dormant black hole in a wide orbit with a red giant star, found from Gaia measurements.El-Badry et al. 2023, A red giant orbiting a black hole
It has about 8.9 times the Sun's mass; its red giant companion takes 1,277 days per orbit.El-Badry et al. 2023, MNRAS 521, 4323El-Badry et al. 2023, the same paper free to read (arXiv)
It was announced in 2023, and Chandra detected no X-rays from it.El-Badry et al. 2023, MNRAS 521, 4323El-Badry et al. 2023, the same paper free to read (arXiv)

Gaia BH34 traced

The most massive known stellar black hole in our galaxy, found in Gaia data in 2024.ESO press release eso2408Gaia Collaboration 2024, Panuzzo et al., Discovery of a dormant 33 solar-mass black hole
It has about 33 times the Sun's mass, the most for a stellar black hole in the Milky Way, as of 2024.ESO press release eso2408, 16 April 2024Gaia Collaboration, Panuzzo et al. 2024, A&A 686, L2Panuzzo et al. 2024, the same paper free to read (arXiv)
Its companion, an old star poor in heavy elements, orbits it every 11.6 years.Gaia Collaboration, Panuzzo et al. 2024, A&A 686, L2Panuzzo et al. 2024, the same paper free to read (arXiv)
It was found in pre-release Gaia DR4 data and announced in April 2024.ESA: Sleeping giant surprises Gaia scientists, 16 April 2024Gaia Collaboration, Panuzzo et al. 2024, A&A 686, L2Panuzzo et al. 2024, the same paper free to read (arXiv)

Cygnus X-14 traced

A black hole feeding on a blue supergiant star, the first X-ray source identified as a stellar-mass black hole.Bambi 2018, Fundamental Concepts (arXiv)MacLeod et al. 2023, Observations of Stellar-Mass Black Holes in the Galaxy (arXiv)Chandra press release, 17 November 2011Orosz et al. 2011, ApJ 742, 84
It was discovered in 1964 by X-ray detectors on a suborbital rocket.MacLeod & Grindlay 2023, Observations of Stellar-Mass Black Holes in the Galaxy (arXiv)
Stephen Hawking bet Kip Thorne in 1974 that it was not a black hole, and conceded in 1990.Chandra press release, 17 November 2011Bambi & Nampalliwar, Fundamental Concepts (arXiv 2018)
Published estimates of its mass range from about 13 to 21 times the Sun's.Orosz et al. 2011, ApJ 742, 84Miller-Jones et al. 2021, Science 371, 1046Ramachandran et al. 2025, Comprehensive UV and optical spectral analysis of Cygnus X-1 (arXiv)

A0620-004 traced

A black hole orbited closely by an orange dwarf star, one of the nearest known black holes.El-Badry et al. 2022, Gaia BH1 (arXiv)Cantrell et al. 2010, ApJ 710, 1127
Its 1975 outburst briefly made it the brightest X-ray source in the sky.Elvis et al. 1975, Nature 257, 656Cantrell et al. 2010, ApJ 710, 1127Cantrell et al. 2010, the same paper free to read (arXiv)
It has about 6.6 times the Sun's mass; its companion orbits every 7.75 hours.Cantrell et al. 2010, ApJ 710, 1127Cantrell et al. 2010, the same paper free to read (arXiv)
It also erupted in 1917, an outburst found only in 1975 on old Harvard photographic plates.Liller, IAU Circular 2823 (1975)Tetarenko et al. 2016, WATCHDOG (arXiv)

V404 Cygni3 traced

A black hole that flares up every few decades as it gulps gas from a companion star.Koninckx et al. 2023, A&A 674, A97 (arXiv); worked out from its numbersKimura et al. 2016, Nature 529, 54 (arXiv)
It has about 9 times the Sun's mass; its companion star orbits every 6.5 days.Khargharia et al. 2010, ApJ 716, 1105Bartolomeo Koninckx et al. 2023, An evolutionary model for the V404 Cyg system (arXiv)
It erupted in 1938, 1956, 1989 and 2015. The 1938 outburst was logged as a nova, the 1956 one was found later on old plates, and the last two were watched in X-rays.BAA Journal: V404 Cygni, a black hole awakensJenke et al. 2016, Fermi GBM observations of V404 Cyg (arXiv)Motta et al. 2017, The black hole binary V404 Cygni (arXiv)

M87*4 traced

The supermassive black hole at the heart of the galaxy Messier 87, the first black hole ever imaged.ESO press release eso1907
It is about 6.5 billion times the Sun's mass.EHT Collaboration 2019, ApJL 875, L1EHT Collaboration 2019, the same paper free to read (arXiv)
The Event Horizon Telescope released its image in April 2019, the first picture of a black hole.ESO press release eso1907, 10 April 2019EHT Collaboration 2019, ApJL 875, L1EHT Collaboration 2019, the same paper free to read (arXiv)
Its glowing ring spans about 42 microarcseconds on the sky.EHT Collaboration 2019, ApJL 875, L1EHT Collaboration 2019, the same paper free to read (arXiv)

The Vela Pulsar4 traced

A young spinning neutron star at the heart of the Vela supernova remnant.Espinoza et al. 2021, Vela pulsar glitches (arXiv)Chandra photo album: Vela Pulsar (2000)
It spins about 11 times a second.Abdo et al. 2010, ApJ 713, 154Abdo et al. 2010, the same paper free to read (arXiv)
It is one of the brightest steady sources of gamma rays in the sky.Abdo et al. 2010, ApJ 713, 154Abdo et al. 2010, the same paper free to read (arXiv)
It is known for glitches, sudden small speed-ups in its spin, seen every few years.Espinoza et al. 2021, Small glitches and other rotational irregularities of the Vela pulsar (arXiv)

Geminga4 traced

A nearby neutron star that shines mainly in gamma rays, one of the brightest gamma-ray sources in the sky.NASA, Fermi links nearby pulsars' gamma-ray halo to antimatter puzzleAbdo et al. 2010, Fermi LAT observations of the Geminga pulsar (arXiv)NASA HEASARC picture of the week: GemingaCaraveo 2014, ARA&A, Gamma-ray Pulsar Revolution
NASA's SAS-2 satellite found it in 1972-73 as a gamma-ray source with no visible counterpart.NASA: Fermi links nearby pulsar's gamma-ray halo to antimatter puzzleJackson et al. 2002, A High-Energy Study of the Geminga Pulsar (arXiv)HEASARC: SAS-2 mission pageHEASARC Picture of the Week: Geminga
Its name is Milanese for 'it's not there', and also stands for Gemini gamma-ray source.NASA: Fermi links nearby pulsar's gamma-ray halo to antimatter puzzleHEASARC Picture of the Week: Geminga
It spins about four times a second and has a spin-down age of around 340,000 years.NASA: Fermi links nearby pulsar's gamma-ray halo to antimatter puzzleMori et al. 2014, NuSTAR and XMM-Newton study of Geminga (arXiv)Bobylev & Bajkova 2009, Astronomy Letters 35, 396 (arXiv)

PSR B1919+214 traced

The first pulsar ever discovered, a spinning neutron star that flashes every 1.337 seconds.Physics Today, Detection of the first pulsar (2017)Shishov et al., Interstellar scintillations of PSR B1919+21 (arXiv)
Jocelyn Bell Burnell and Antony Hewish discovered it in 1967.Bell Burnell, Little Green Men, White Dwarfs or Pulsars?, Cosmic Search 1979Physics Today: Detection of the first pulsarHewish et al. 1968, Nature 217, 709
It was jokingly labelled LGM-1, for 'little green men', before its natural origin was clear.Physics Today: Detection of the first pulsarMuseum of Science: All About Pulsars
Its pulses appear on the cover of Joy Division's 1979 album Unknown Pleasures.UW-Milwaukee CGCA: Unknown Pleasures of Known Pulsars

RX J1856.5-37544 traced

One of the nearest known neutron stars, a cooling stellar corpse seen by its own heat, with no radio pulses.Walter et al. 2010, Revisiting the parallax of RX J1856 (arXiv)Haberl 2007, The Magnificent Seven (arXiv)Walter 2001, Proper motion, parallax and origin of RX J185635-3754 (arXiv)
At about 400 light years, it is one of the nearest known neutron stars.Walter et al. 2010, ApJ 724, 669Walter et al. 2010, the same paper free to read (arXiv)
It belongs to the 'Magnificent Seven', isolated neutron stars that glow in X-rays from leftover heat.Haberl 2007, The Magnificent Seven (arXiv)Kaplan 2008, Nearby, Thermally Emitting Neutron Stars (arXiv)Walter et al. 2010, ApJ 724, 669
It was found in ROSAT X-ray data and reported as a nearby isolated neutron star in 1996.Walter, Wolk & Neuhauser 1996, Nature 379, 233Walter et al. 2010, ApJ 724, 669Neuhauser 2001, The proper motion of the neutron star RXJ1856.5-3754 (arXiv)

SGR 1806-204 traced

A magnetar, a neutron star with an extreme magnetic field, at a disputed distance: about as far as the Milky Way's centre, perhaps nearly twice that.Crowther et al. 2011, downward revision in distance to SGR 1806-20 (arXiv); worked out from its numbersMcClure-Griffiths & Gaensler 2005 (arXiv)Svirski et al. 2011, MNRAS 415, 2485GRAVITY Collaboration 2019, distance to the Galactic Centre (arXiv)
Its giant flare on 27 December 2004 was the brightest event recorded from beyond the Solar System up to then.Palmer et al. 2005, Nature 434, 1107Palmer et al. 2005, the same paper free to read (arXiv)
That flare measurably disturbed Earth's upper atmosphere from tens of thousands of light years away.Gaensler et al. 2005, Nature 434, 1104Gaensler et al. 2005, the same paper free to read (arXiv)
Published estimates run from about 7 to 15 kiloparsecs; the widest limits allow about 6 to 19.Boggs et al., The Giant Flare of December 27, 2004 (arXiv)Crowther et al. 2011, Contamination of short GRBs by giant magnetar flares (arXiv) (Advances in Space Research 47 (2011) 1341-1345)McClure-Griffiths & Gaensler 2005, Constraints on the distance from H I absorption (arXiv)Svirski et al. 2011, MNRAS 415, 2485

PSR J0437-47154 traced

The nearest and brightest millisecond pulsar known, a neutron star spinning about 174 times a second.Choudhury et al. 2024, A NICER view of the nearest and brightest millisecond pulsar (arXiv)Reardon et al. 2024, ApJL
It spins about 174 times a second.Reardon et al. 2024, ApJL 971, L18Reardon et al. 2024, the same paper free to read (arXiv)
Its mass, about 1.42 Suns, is known precisely from its orbit with a white dwarf.Reardon et al. 2024, ApJL 971, L18Reardon et al. 2024, the same paper free to read (arXiv)
A 2024 NICER analysis put its radius at about 11.4 km; a 2025 reanalysis of NICER data gets about 12 to 15 km.Choudhury et al. 2024, ApJL 971, L20Miller et al. 2025, The Radius of PSR J0437-4715 from NICER Data (arXiv)

Sirius B4 traced

The white dwarf companion of Sirius, the brightest star in the night sky.Bond et al. 2017, ApJ 840, 70Bond et al. 2017, the same paper free to read (arXiv)
It packs about 1.02 Suns of mass into a ball slightly smaller than Earth.Bond et al. 2017, ApJ 840, 70Bond et al. 2017, the same paper free to read (arXiv)
Friedrich Bessel predicted it in 1844 from Sirius's wobble; Alvan Graham Clark first saw it in 1862.Bond et al. 2017, ApJ 840, 70Bond et al. 2017, the same paper free to read (arXiv)
It is the nearest known white dwarf to the Sun.Bond et al. 2017, ApJ 840, 70Bond et al. 2017, the same paper free to read (arXiv)

40 Eridani B4 traced

The first white dwarf ever recognised, part of a triple star system in Eridanus.Bond et al. 2017, ApJ 848, 16Bond et al. 2017, the same paper free to read (arXiv)
Henry Norris Russell, Edward Pickering and Williamina Fleming recognised its strange nature in 1910.Bond et al. 2017, ApJ 848, 16Bond et al. 2017, the same paper free to read (arXiv)
It shares its system with an orange dwarf and a red dwarf.Bond et al. 2017, ApJ 848, 16Bond et al. 2017, the same paper free to read (arXiv)
It has about 0.57 Suns of mass in a body about 1.4 times Earth's width.Bond et al. 2017, ApJ 848, 16Bond et al. 2017, the same paper free to read (arXiv)

Van Maanen's Star3 traced

The nearest known solitary white dwarf, discovered by Adriaan van Maanen in 1917.Kervella et al. 2019, A&A (arXiv)
Adriaan van Maanen discovered it in 1917 from its fast motion across the sky.Farihi 2016, New Astron. Rev. 71, 9Farihi 2016, the same paper free to read (arXiv)
Its 1917 spectrum is now seen as the earliest evidence of planetary debris around another star.Farihi 2016, New Astron. Rev. 71, 9Farihi 2016, the same paper free to read (arXiv)

Proxima Centauri4 traced

The nearest known star to the Sun, a small red dwarf with at least one planet of about Earth's mass or more.Anglada-Escude et al. 2016, Nature 536, 437Anglada-Escude et al. 2016, the same paper free to read (arXiv)
It has about 12% of the Sun's mass and orbits Alpha Centauri A and B every 550,000 years or so.Kervella et al. 2017, A&A 598, L7Kervella et al. 2017, the same paper free to read (arXiv)
Its planet Proxima b, found in 2016, orbits every 11.2 days in the star's habitable zone.Anglada-Escude et al. 2016, Nature 536, 437Anglada-Escude et al. 2016, the same paper free to read (arXiv)
Proxima b has at least 1.055 times Earth's mass, per the NASA Exoplanet Archive as of October 2026.NASA Exoplanet Archive, composite parameters for Proxima Cen b (query run 2026-11-01)Suarez Mascareno et al. 2025, A&A 700, A11 (arXiv; reference from the Exoplanet Archive)

Barnard's Star4 traced

The nearest single star to the Sun, a red dwarf moving faster across the sky than any other star.Gonzalez Hernandez et al. 2024, A&ABasant et al. 2025 (arXiv)
It has the largest proper motion of any known star, about 10.4 arcseconds per year.Basant et al. 2025, ApJL 982, L1Basant et al. 2025, the same paper free to read (arXiv)Gonzalez Hernandez et al. 2024, A&A 690, A79Gonzalez Hernandez et al. 2024, the same paper free to read (arXiv)
E. E. Barnard measured its motion in 1916.Barnard 1916, AJ 29, 181: A small star with large proper-motionGonzalez Hernandez et al. 2024, A&A 690, A79Gonzalez Hernandez et al. 2024, the same paper free to read (arXiv)
Four small planets around it were confirmed in 2025.Basant et al. 2025, ApJL 982, L1Basant et al. 2025, the same paper free to read (arXiv)

Wolf 3594 traced

One of the nearest red dwarfs, a small flare star in Leo.Pietras et al. 2023, X-class flare on Wolf 359 (arXiv)Lin et al. 2022, AJ
It has about 11% of the Sun's mass.Pineda et al. 2021, ApJ
Max Wolf discovered it photographically.HyperPhysics, Georgia State University: Lalande 21185 and nearby stars
It is a flare star whose brightness can jump suddenly.Lin et al. 2022, simultaneous optical flares of Wolf 359

Lalande 211854 traced

A nearby red dwarf of about magnitude 7.5, among the closest star systems to the Sun.Stock et al. 2020, A&A, CARMENES (arXiv)
It is among the brightest red dwarfs in the solar neighbourhood.HyperPhysics, Georgia State University: Lalande 21185 and nearby stars
Jérôme Lalande catalogued it in his 1801 star catalogue.HyperPhysics, Georgia State University: Lalande 21185 and nearby starsSelected astrometric catalogues (2017), reference: Lalande J. 1801, Histoire Celeste Francaise
It has about 39% of the Sun's mass.Stock et al. 2020, A&A (CARMENES)

Luhman 165 traced

A pair of brown dwarfs orbiting each other, the nearest known brown dwarfs to the Sun.Bedin et al. 2017, HST astrometry of the closest brown dwarf binary (arXiv)Luhman 2013, discovery (arXiv)
Kevin Luhman discovered the pair in 2013 using WISE data.Luhman 2013, ApJL, Discovery of a binary brown dwarf at 2 parsecsPenn State, The Closest Star System Found in a Century (2013)
It is the third-closest known system to the Sun, after Alpha Centauri and Barnard's Star.Penn State, The Closest Star System Found in a Century (2013)Bedin et al. 2017, MNRASLuhman 2013, ApJL
The two have about 34 to 35 and 28 to 29 times Jupiter's mass.Bedin et al. 2024, MNRAS (HST astrometry II)Apai et al. 2021 (TESS), citing Ammons & GarciaHigh-resolution atlas of Luhman 16AB (2025), citing Lazorenko & Sahlmann 2018
Astronomers have mapped what are probably patchy clouds on one of them.Crossfield et al. 2014, NatureCrossfield et al. 2014 (preprint)

WISE 0855-07144 traced

The coldest known brown dwarf, a dark, Jupiter-like object drifting near the Sun.Luhman et al. 2024, JWST/NIRSpec observations of the coldest known brown dwarf (arXiv)Skemer et al. 2016 (arXiv)Luhman 2014, discovery (arXiv)
Its temperature is roughly 250 to 290 kelvin, around the freezing point of water.Luhman et al. 2024, AJ (JWST/NIRSpec)Luhman et al. 2024, AJLuhman 2014, ApJL
Kevin Luhman discovered it in 2014 using WISE and Spitzer data.Luhman 2014, ApJL
Its mass is estimated at a few to about ten times Jupiter's.Luhman 2014, ApJL

Epsilon Eridani4 traced

A young Sun-like star nearby, with a giant planet and dusty rings like our Kuiper belt.Mawet et al. 2019, AJ (arXiv)Kaler, Stars: Tau Ceti
It is younger than the Sun, at about 200 to 800 million years.Mamajek & Hillenbrand 2008, ApJ (table: 0.4 and 0.8 Gyr)Mawet et al. 2019, AJ
A giant planet about two-thirds to three-quarters of Jupiter's mass orbits it every 7.4 years.Llop-Sayson et al. 2021, AJMawet et al. 2019, AJ
It was a target of Project Ozma, Frank Drake's 1960 search for alien radio signals.SETI Institute, Project OzmaNRAO Historical Radio Astronomy Working Group, Frank D. Drake memoir

Tau Ceti4 traced

The nearest single star similar to the Sun, a slightly smaller and older yellow star.Dietrich & Apai 2021, AJ (arXiv)Kaler, Stars: Tau CetiTeixeira et al. 2009, A&A (arXiv)
It is the nearest solitary G-type star, the same class as the Sun.Dietrich & Apai 2021, AJ
Frank Drake observed it in Project Ozma in 1960.SETI Institute, Project OzmaNRAO Historical Radio Astronomy Working Group, Frank D. Drake memoir
Four planet candidates around it were reported in 2017.Feng et al. 2017, AJ

Eta Carinae4 traced

A pair of very massive stars inside the Carina Nebula, famous for a giant eruption in the 1840s.NASA, Hubble's Caldwell Catalog: Caldwell 92NASA, Astronomers Bring the Third Dimension to a Doomed Star's Outburst
During its 'Great Eruption' in the 1840s it briefly became the second-brightest star in the sky.NASA, Astronomers Bring the Third Dimension to a Doomed Star's Outburst
That outburst threw off the Homunculus Nebula, at least 10 Suns' worth of gas.NASA, Astronomers Bring the Third Dimension to a Doomed Star's OutburstNASA Science, Eta Carinae (Hubble image)
Its two stars total over 100 Suns and orbit each other every 5.54 years.NASA, Astronomers Bring the Third Dimension to a Doomed Star's OutburstGull et al. 2022, ApJ (NASA NTRS)

VY Canis Majoris4 traced

A red hypergiant, one of the largest known stars, wrapped in dust it is shedding.NASA Hubble, Hubble Solves Mystery of Monster Star's DimmingUniversity of Minnesota, Red hypergiant VY CMa
Its radius is about 1,420 times the Sun's.Wittkowski et al. 2012, A&AWittkowski et al. 2012, A&A
Placed at the Sun, it would reach beyond the orbit of Jupiter.NASA, Astronomers Map a Hypergiant Star's Massive OutburstsUniv. of Minnesota, The Red Hypergiant VY CMa
It is losing mass fast, wrapped in clouds of its own dust.Univ. of Minnesota, The Red Hypergiant VY CMaNASA, Hubble Solves Mystery of Monster Star's Dimming

Mira5 traced

A pulsating red giant that brightens and fades over about 11 months, the prototype of the long-period variables named after it.Templeton et al. 2009, ApJ 691, 1470, Long-Period Variability in o Ceti (arXiv); worked out from its numbersKaler, Stars: Mira
It swings from about magnitude 3, sometimes 2, down to 10 over a cycle of about 332 days.Zamanov et al. 2019 (332 days, about 7 mag, citing Hoffleit 1997)J. Kaler, University of Illinois: Mira
David Fabricius is credited with discovering its changing brightness in 1596.AAVSO, Variable Star of the Season: Mira RevisitedAAVSO, Variable Star of the Season: Omicron Ceti (Mira)
In 2007 the GALEX telescope found a 13-light-year tail of gas trailing behind it.NASA Science Photojournal, Mira Soars Through the SkyAPOD 2007 August 17
Johannes Hevelius named it Mira, "The Wonderful", in 1642.AAVSO, Variable Star of the Season: Omicron Ceti (Mira)

T Coronae Borealis3 traced

A recurrent nova: a white dwarf that steals gas from a red giant and flared up in 1866 and 1946, 80 years apart.Schaefer 2023, MNRAS (arXiv)
It erupted in 1866 and 1946, each time reaching about magnitude 2.Schaefer 2023, MNRAS
Its white dwarf and red giant orbit each other every 228 days.Schaefer 2023, MNRAS

Tabby's Star4 traced

A star whose light dips irregularly and deeply, now thought to be caused by dust.Boyajian et al. 2016, MNRAS (arXiv)Boyajian et al. 2018, ApJL (arXiv)
Planet Hunters volunteers flagged its strange dips, up to 22% deep, in Kepler data.Boyajian et al. 2016, MNRAS (Planet Hunters X)
It is named for Tabetha Boyajian, lead author of the 2016 study.NASA Astrobiology, The Ever More Puzzling and Intriguing Tabby's StarPenn State release (2018)Boyajian et al. 2016, MNRAS
Its dips are deeper in blue light, pointing to fine dust rather than a solid structure.Boyajian et al. 2018, ApJLNASA JPL, Mysterious Dimming of Tabby's Star May Be Caused by Dust

WR 1043 traced

A pair of hot massive stars whose colliding winds wind dust into a pinwheel spiral.Tuthill et al. 2008, The prototype colliding-wind pinwheel WR 104 (arXiv)
Its colliding stellar winds form a spiral of dust, first imaged in 1999.Tuthill et al. 2008, ApJ (The prototype colliding-wind pinwheel WR 104)
The spiral turns once every 241 days, the orbit of its two stars.Tuthill et al. 2008, ApJ

TRAPPIST-15 traced

An ultracool dwarf star with seven Earth-sized, probably rocky planets, three in its habitable zone.NASA news release, February 2017ESO press release eso1706Agol et al. 2021, PSJ (arXiv)
It has seven known Earth-sized planets, the first such system known.NASA release on TRAPPIST-1 (Feb 2017)
All seven orbit closer than Mercury does to the Sun, with years of 1.5 to 19 days.NASA release on TRAPPIST-1 (Feb 2017)Agol et al. 2021, PSJ
Three of the planets lie in the star's habitable zone.NASA release on TRAPPIST-1 (Feb 2017)ESO eso1706
It is named for the TRAPPIST telescope in Chile, which found its first planets in 2016.NASA release on TRAPPIST-1 (Feb 2017)ESO eso1615

51 Pegasi4 traced

A Sun-like star whose planet, found in 1995, was the first known around a star like the Sun.Nobel Prize in Physics 2019, press release
Its planet 51 Pegasi b was the first found orbiting a Sun-like star, in 1995.Nobel Prize in Physics 2019, press releaseNASA Science, 30 Years of Exoplanets
Michel Mayor and Didier Queloz won the 2019 Nobel Prize in Physics for the discovery.Nobel Prize in Physics 2019, summary
The planet circles its star every 4.23 days, with at least about half Jupiter's mass.Nobel Committee, Scientific Background 2019

HD 2094584 traced

A Sun-like star with a hot Jupiter, the first planet seen passing in front of its star.ESA/Hubble heic0403Charbonneau et al. 2000, Detection of Planetary Transits Across a Sun-like Star (arXiv)
Its planet was the first seen to transit its star, in 1999.ESA/Hubble heic0403Charbonneau et al. 2000, ApJL
It was the first exoplanet whose atmosphere was detected, in Hubble results announced in 2001.ESA/Hubble heic0403Charbonneau et al. 2002, ApJ
Nicknamed Osiris, the planet orbits every 3.5 days and is losing hydrogen into space.Vidal-Madjar & Lecavelier des Etangs 2004NASA, Too Close for Comfort: Hubble Discovers an Evaporating Planet

Kepler-1864 traced

A red dwarf with five known planets, including the first Earth-sized planet found in a habitable zone.NASA release 14-111Quintana et al. 2014, Science (arXiv)
Kepler-186f, announced in 2014, was the first Earth-sized planet found in another star's habitable zone.NASA release (2014)Quintana et al. 2014, Science
Kepler-186f is about 1.17 times Earth's radius and orbits every 130 days.Torres et al. 2015, ApJ (Validation of twelve small Kepler planets)
Its star is a red dwarf with about 54% of the Sun's mass.Torres et al. 2015, ApJ (Validation of twelve small Kepler planets)Quintana et al. 2014, Science

Kepler-4524 traced

A Sun-like star whose reported planet, Kepler-452b, was announced in 2015 as lying in its habitable zone.Jenkins et al. 2015, AJ 150, 56 (arXiv)Mullally et al. 2018, AJ (arXiv)
Kepler-452b was announced in 2015 as a planet in a Sun-like star's habitable zone.Jenkins et al. 2015, AJ
Its year lasts about 385 days.Jenkins et al. 2015, AJ
Later analyses of Kepler data questioned whether the planet is real.Mullally et al. 2018, AJMullally et al. 2018 (preprint)

TOI-7004 traced

A quiet red dwarf with two Earth-sized planets in its habitable zone, found by NASA's TESS.Gilbert et al. 2020, AJ (arXiv)Gilbert et al. 2023, ApJL (arXiv)
TOI-700 d, found in 2020, was TESS's first Earth-sized planet in a habitable zone.Gilbert et al. 2023, ApJLGilbert et al. 2020, AJ
A second Earth-sized habitable-zone planet, TOI-700 e, was announced in 2023.Gilbert et al. 2023, ApJL
The star has about 42% of the Sun's mass.Gilbert et al. 2020, AJGilbert et al. 2023, ApJL

HR 87994 traced

A young star with four giant planets photographed directly, the first multi-planet system imaged.Metchev et al. 2009, ApJ 705, L204 (arXiv)Marois et al. 2010, Nature (arXiv)
Its planets were the first multi-planet system directly imaged, announced in 2008.Metchev et al. 2009, ApJL (pre-discovery image of HR 8799)Marois et al. 2008, ScienceESO eso2609
Four giant planets, each several times Jupiter's mass, orbit about 15 to 70 AU out.Wang et al. 2018, AJMarois et al. 2010, NatureMarois et al. 2008, Science
The star is only about 30 to 40 million years old.Marois et al. 2010, Nature (30 Myr Columba)Wang et al. 2018 (citing Bell et al. 2015)

Beta Pictoris3 traced

A young star with a dusty disc seen edge-on and three known giant planets.NASA Exoplanet Archive, beta Pic planets (default parameters)NASA Hubble, two dust disks around Beta PictorisMiret-Roig et al. 2020, A&A (arXiv)
In 1984 it became the first star imaged with a disc of dust around it.Boccaletti et al. 2009, A&A (VLT/NACO, beta Pic)NASA, Hubble Reveals Two Dust Disks Around Beta Pictoris
The star is only about 20 million years old (estimates run about 18 to 25).Miret-Roig et al. 2020, A&AMamajek & Bell 2014, MNRAS

K2-184 traced

A red dwarf whose planet K2-18 b, a sub-Neptune in the habitable zone, has been studied by JWST.Benneke et al. 2019, ApJL (arXiv)Madhusudhan et al. 2023, ApJL (arXiv)
K2-18 b is about 8.9 times Earth's mass per the NASA Exoplanet Archive as of October 2026 (other measurements go down to 7.2), and orbits in its star's habitable zone.NASA Exoplanet Archive, K2-18 bSarkis et al. 2018, AJSarkis et al. 2018, the same paper free to read (arXiv)Benneke et al. 2019, ApJLBenneke et al. 2019, the same paper free to read (arXiv)
JWST detected methane in 2023 and also reported carbon dioxide. A 2025 reanalysis confirmed the methane but not the CO2; a 2025 preprint on newer JWST data detects both.Madhusudhan et al. 2023Schmidt et al. 2025 (reanalysis)Hu et al. 2025 (new JWST data)
Claims of a possible biosignature gas there are disputed and unconfirmed.Madhusudhan et al. 2025, the claim (DMS/DMDS at 3 sigma)Schmidt et al. 2025Taylor 2025

55 Cancri4 traced

A binary star system whose main star hosts five known planets, including a lava-covered super-Earth.Fischer et al. 2008, ApJ (arXiv)NASA exoplanet catalog: 55 Cancri e
Five known planets orbit its main star.Fischer et al. 2008, ApJFischer et al. 2008, the same paper free to read (arXiv)
55 Cancri e circles in under 18 hours and may have a molten surface.NASA Exoplanet Archive, 55 Cnc eHu et al. 2024, NatureHu et al. 2024, the same paper free to read (arXiv)NASA exoplanet catalog, 55 Cancri e
The IAU named the main star Copernicus in 2015.IAU press release iau1514, 15 Dec 2015 (archived copy)

WASP-394 traced

A star with a puffy hot Saturn, WASP-39b, one of the first planets JWST studied in detail.NASA, Webb detects carbon dioxide in exoplanet atmosphere
JWST made the first clear detection of carbon dioxide in an exoplanet atmosphere here, in 2022.NASA, Webb detects carbon dioxide in exoplanet atmosphere, 25 Aug 2022JWST Transiting Exoplanet Community ERS Team 2023, Nature 614, 649JWST Transiting Exoplanet Community ERS Team 2023, the same paper free to read (arXiv)
WASP-39b has about Saturn's mass but is 1.27 times Jupiter's width.Faedi et al. 2011, A&AFaedi et al. 2011, the same paper free to read (arXiv)
It orbits its star every 4 days.Faedi et al. 2011, A&AFaedi et al. 2011, the same paper free to read (arXiv)

LHS 11404 traced

A red dwarf whose planet LHS 1140 b, probably a water world or a small mini-Neptune, lies in its habitable zone and has been studied by JWST.Cadieux et al. 2024, ApJL (arXiv)Cadieux et al. 2024, JWST/NIRISS (arXiv)
LHS 1140 b has about 5.6 Earth masses and orbits in its star's habitable zone.Cadieux et al. 2024 (LHS 1140 mass and radius)Cadieux et al. 2024 (JWST/NIRISS spectrum)
Its year lasts about 25 days.NASA Exoplanet Archive, LHS 1140 b
Its low density suggests it may be rich in water, at 9 to 19% of its mass. JWST data in 2024 ruled out a hydrogen-rich atmosphere, but did not show water.Cadieux et al. 2024 (LHS 1140 mass and radius)Cadieux et al. 2024 (JWST/NIRISS spectrum)

The Local Bubble5 traced

A cavity of hot, thin gas about 1,000 light years across that surrounds the Sun, carved by supernovae.Zucker et al. 2022, NatureZucker et al. 2022, the same paper free to read (arXiv)Harvard CfA news, January 2022
It is about 1,000 light years across, and the Sun lies near its middle.Center for Astrophysics, Harvard & Smithsonian, news release, 12 Jan 2022Zucker et al. 2022, Nature 601, 334Zucker et al. 2022, the same paper free to read (arXiv)
It was carved by about 15 supernovae over the past 14 million years.Zucker et al. 2022, Nature 601, 334Zucker et al. 2022, the same paper free to read (arXiv)Center for Astrophysics, Harvard & Smithsonian, news release, 12 Jan 2022
Nearly all star-forming clouds near the Sun lie on its surface.Zucker et al. 2022, Nature 601, 334Zucker et al. 2022, the same paper free to read (arXiv)
The Sun entered it about 5 million years ago.Zucker et al. 2022, Nature 601, 334Zucker et al. 2022, the same paper free to read (arXiv)

The Radcliffe Wave5 traced

A long, wave-shaped chain of star-forming gas clouds near the Sun, including Orion and Cygnus.Konietzka et al. 2024, NatureKonietzka et al. 2024, the same paper free to read (arXiv)Alves et al. 2020, NatureAlves et al. 2020, the same paper free to read (arXiv)
It is about 8,800 light years long, from Canis Major to Cygnus.Alves et al. 2020, NatureAlves et al. 2020, the same paper free to read (arXiv)Konietzka et al. 2024, NatureKonietzka et al. 2024, the same paper free to read (arXiv)
Its crests rise about 500 light years above and below the galaxy's disc.Alves et al. 2020, NatureAlves et al. 2020, the same paper free to read (arXiv)
It was found in 2020 using Gaia data, and named for the early women astronomers of Radcliffe College and for Harvard's Radcliffe Institute.Alves et al. 2020, NatureAlves et al. 2020, the same paper free to read (arXiv)
In 2024 astronomers found that it oscillates, moving up and down like a wave.Konietzka et al. 2024, NatureKonietzka et al. 2024, the same paper free to read (arXiv)

The Local Interstellar Cloud4 traced

The wisp of thin, warm interstellar gas around the Solar System, which sits very close to its edge.Linsky, Redfield & Tilipman 2019, ApJLinsky et al. 2019, the same paper free to read (arXiv)
The Sun lies near its edge and may leave it within the next few thousand years.Linsky, Redfield & Tilipman 2019, ApJLinsky et al. 2019, the same paper free to read (arXiv)
Its gas is about 6,300 to 7,500 kelvin but extremely thin: about 0.2 hydrogen atoms per cubic centimetre near the Sun, perhaps 0.1 across the cloud.Linsky, Redfield & Tilipman 2019, ApJLinsky et al. 2019, the same paper free to read (arXiv)Linsky et al. 2022, AJLinsky et al. 2022, the same paper free to read (arXiv)
The Solar System is thought to have entered it within the past 40,000 years. Estimates run from under 10,000 to about 40,000 years ago.Frisch & Slavin 2006, Astrophys. Space Sci. Trans. 2, 53Frisch & Slavin 2006, the same paper free to read (arXiv)

Voyager 17 traced

NASA's space probe launched in 1977, the most distant human-made object.NASA Science: Voyager 1
Launched on 5 September 1977, it flew past Jupiter in 1979 and Saturn in 1980.NASA, Voyager 1 mission page
It became the first spacecraft to enter interstellar space, in August 2012.NASA, Voyager 1 mission page
Radio signals take about 24 hours to reach it: NASA dates its arrival at one light-day from Earth to 18 November 2026.NASA, Voyager 1 mission pageJPL Horizons ephemeris; one-way light time
Before Jupiter it was too slow to ever leave the Sun: 13.7 km/s, with 19.1 needed there. Jupiter's pull changed that.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the pass
Jupiter, 5 March 1979: 13.7 → 23.3 km/s against the Sun.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the passNASA, Voyager 1 mission page
Saturn, 12 November 1980: 20.3 → 21.4 km/s against the Sun.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the passNASA, Voyager 1 mission page

Voyager 28 traced

NASA's space probe launched in 1977, the only spacecraft to visit Uranus and Neptune.NASA Science: Voyager 2
It entered interstellar space in November 2018.NASA, Voyager 2 mission pageStone et al. 2019, Nature Astronomy
Before Jupiter it was too slow to ever leave the Sun: 10.5 km/s, with 18.8 needed there. Jupiter took it just past the line.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the pass
Jupiter, 9 July 1979: 10.5 → 19.5 km/s against the Sun.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the passNASA, Voyager 2 mission page
Saturn, 26 August 1981: 15.8 → 20.3 km/s against the Sun.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the passNASA, Voyager 2 mission page
Uranus, 24 January 1986: 18.0 → 19.7 km/s against the Sun.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the passNASA, Voyager 2 mission page
Neptune, 25 August 1989: 18.9 → 16.7 km/s against the Sun.JPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the passNASA, Voyager 2 mission page
Neptune slowed it: the close pass over the planet's north pole bent its path south, out of the planets' plane. It no longer needed the speed.NASA, 30 Years Ago: Voyager 2 Explores NeptuneNASA/JPL Photojournal PIA02215NASA, Planetary VoyageJPL Horizons ephemeris; speeds worked out from its velocity vectors, months either side of the pass

Pioneer 104 traced

NASA's probe launched in 1972, the first to cross the asteroid belt and fly past Jupiter.NASA Science: Pioneer 10
Launched in March 1972, it flew past Jupiter in December 1973.NASA, Pioneer 10 mission page
Its last signal was received on 23 January 2003.NASA, Pioneer 10 mission page
It carries a gold plaque showing a man, a woman and the Sun's place in the galaxy.NASA, Contact with Pioneer 10NSSDCA, Pioneer 10NASA, Pioneer 10 mission page

Pioneer 113 traced

NASA's probe launched in 1973, the first spacecraft to fly past Saturn.NASA Science: Pioneer 11
Launched in April 1973, it flew past Jupiter in 1974 and Saturn in September 1979.NASA, Pioneer 11 mission page
Its mission ended in 1995 when its power ran too low.NASA Pioneer 11 end-of-operations release, 1995NSSDCA, Pioneer 11NASA, Pioneer 11 mission page

New Horizons3 traced

NASA's probe that flew past Pluto in 2015 and the Kuiper belt object Arrokoth in 2019.NASA Science: New Horizons
Launched in January 2006, it flew past Pluto on 14 July 2015.NASA, New Horizons mission page
On 1 January 2019 it flew past Arrokoth, the most distant object explored up close, as of 2025.NASA, New Horizons mission page

Messier 23 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 2Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It sits in Aquarius, about 5 degrees north of Beta Aquarii.NASA Hubble Messier catalog, Messier 2Baumgardt globular cluster database, parameter table; the separation worked out from positionsBright Star Catalogue, NASA HEASARC (HR 8232); the separation worked out from positions
It holds about 624,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 53 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 5Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is perhaps the most spectacular globular cluster visible from the northern hemisphere, and can be seen with the naked eye under excellent conditions.NOIRLab, M5, NGC 5904
It holds about 392,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 93 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 9Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is one of the globular clusters closest to the Milky Way's centre, dimmed by dust in front of it.Arellano Ferro et al. 2013, MNRASArellano Ferro et al. 2013, the same paper free to read (arXiv)Alonso-García et al. 2012, AJ 143, 70Alonso-García et al. 2012, the same paper free to read (arXiv)NASA Hubble Messier catalog, Messier 9
Messier discovered it in 1764.NASA Hubble Messier catalog, Messier 9

Messier 103 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 10Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It and Messier 12 sit only about 3 degrees apart in Ophiuchus.Baumgardt globular cluster database, parameter table; the separation worked out from positionsNASA Hubble Messier catalog, Messier 10NASA Hubble Messier catalog, Messier 12
It holds about 189,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 123 traced

A globular cluster: more than 100,000 very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 12Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is loosely packed for a globular, and has lost many of its low-mass stars to the Milky Way's tides.NASA Hubble Messier catalog, Messier 12
It holds about 106,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 143 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 14Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
A nova erupted inside it in 1938. It was only found on photographs taken that year in 1963, and reported in 1964.NASA, Hubble Space Telescope Searches for a Historic Nova in M14Zhao et al. 2024, MNRASZhao et al. 2024, the same paper free to read (arXiv)NASA Hubble Messier catalog, Messier 14
It holds about 595,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 193 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 19Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is one of the most flattened globular clusters known.Piotto et al. 1999, AJPiotto et al. 1999, the same paper free to read (arXiv)NASA Hubble Messier catalog, Messier 19
It holds about 719,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 283 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 28Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It was the first globular cluster found to hold a millisecond pulsar, discovered in 1986 and published in 1987.NASA Hubble Messier catalog, Messier 28Lyne et al. 1987, Nature 328, 399
It holds about 270,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt globular cluster database, parameter table

Messier 303 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 30Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
Its core is thought to have collapsed: its stars crowd far more tightly towards the middle than in most globulars.Ferraro et al. 2009, NatureFerraro et al. 2009, the same paper free to read (arXiv)
It holds about 121,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 533 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 53Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is one of the more distant globular clusters in Messier's list, out in the Milky Way's halo.Dékány & Kovács 2009, A&A 507, 803Dékány & Kovács 2009, the same paper free to read (arXiv)Baumgardt, Galactic Globular Cluster Database (parameter table)NASA, Hubble's Messier Catalog: Messier 53
It holds about 502,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 543 traced

A massive globular cluster that belongs to another galaxy: it sits at the heart of the Sagittarius Dwarf Spheroidal Galaxy, which the Milky Way is tearing apart.NASA, Hubble's Messier Catalog: Messier 54Bellazzini et al. 2008, AJ (arXiv)Bellazzini et al. 2003, AJ (arXiv)Baumgardt, Globular cluster database, parameters
It is one of four globular clusters once thought to be the Milky Way's own that were found to belong to the Sagittarius dwarf galaxy, discovered in 1994.Bellazzini, Ferraro & Ibata 2003, AJNASA, Hubble's Messier Catalog: Messier 54
It holds about 1.59 million times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 553 traced

A globular cluster: around 100,000 or more very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 55Baumgardt, Globular cluster database, parametersBaumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
Nicolas-Louis de Lacaille found it around 1751–52 from South Africa.Steinicke, historical NGC/IC dataNASA, Hubble's Messier Catalog: Messier 55
It holds about 197,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 563 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 56Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It lies in Lyra, roughly halfway between Albireo and Sulafat.NASA, Hubble's Messier Catalog: Messier 56Steinicke, historical NGC/IC data; worked out from its numbersHipparcos new reduction, positions via the ESA Gaia archive; worked out from its numbers
It holds about 166,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 623 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 62Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is one of the most irregularly shaped globulars in the Milky Way, perhaps because it sits so close to the galaxy's centre and feels its tides.NASA, Hubble's Messier Catalog: Messier 62
It holds about 581,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 683 traced

A globular cluster: more than 100,000 very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 68Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
Its stars are among the poorest in heavy elements of any globular cluster.Kains et al. 2015, A&A 578, A128Kains et al. 2015, the same paper free to read (arXiv)
It holds about 128,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 693 traced

A globular cluster: more than 100,000 very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 69Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
It is one of the globulars richest in heavy elements.NASA, Hubble's Messier Catalog: Messier 69
Messier discovered it in 1780.NASA, Hubble's Messier Catalog: Messier 69Steinicke, historical NGC/IC data

Messier 703 traced

A globular cluster: more than 100,000 very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 70Baumgardt, Globular cluster database, parametersNASA, Hubble's Messier Catalog: Messier 71Baumgardt, Globular cluster database, orbitsVandenBerg et al. 2013, ApJ 775, 134VandenBerg et al. 2013, the same paper free to read (arXiv)
Its core has collapsed into a dense, bright centre.NASA, Hubble's Messier Catalog: Messier 70
It holds about 105,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 713 traced

A sparse globular cluster in Sagitta, so loose that for many years it was taken for an open cluster, until the 1970s.NASA, Hubble's Messier Catalog: Messier 71
It is a metal-rich globular cluster, about 11 to 12 billion years old.Di Cecco et al. 2015, AJ 150, 51Di Cecco et al. 2015, the same paper free to read (arXiv)
It holds about 37,800 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 723 traced

A globular cluster: tens of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 72; worked out from its numbersNASA, Hubble's Messier Catalog: Messier 107NASA, Hubble's Messier Catalog: Messier 92Baumgardt, globular cluster parameter database
It is one of the fainter and more distant globulars in Messier's list.NASA, Hubble's Messier Catalog: Messier 72Baumgardt, Galactic Globular Cluster Database (parameter table)
Pierre Méchain discovered it in 1780.NASA, Hubble's Messier Catalog: Messier 72Steinicke, historical NGC/IC data

Messier 753 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 75NASA, Hubble's Messier Catalog: Messier 107NASA, Hubble's Messier Catalog: Messier 92Baumgardt, globular cluster parameter database
It is one of the most densely packed globular clusters known.ESA/Hubble Picture of the Week potw1916a, Crowded clusterNASA, Hubble's Messier Catalog: Messier 75
It holds about 459,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 793 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 79NASA, Hubble's Messier Catalog: Messier 107NASA, Hubble's Messier Catalog: Messier 92Baumgardt, globular cluster parameter database
It is unusual in being seen in the winter sky, on the far side of the sky from the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 79
It holds about 181,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 803 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 80NASA, Hubble's Messier Catalog: Messier 107NASA, Hubble's Messier Catalog: Messier 92Baumgardt, globular cluster parameter database
In 1860 a nova, T Scorpii, flared inside it and briefly outshone the whole cluster.Dieball et al. 2010, ApJ 710, 332Dieball et al. 2010, the same paper free to read (arXiv)NASA, Hubble's Messier Catalog: Messier 80
It holds about 321,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 923 traced

A globular cluster: hundreds of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 92NASA, Hubble's Messier Catalog: Messier 107Baumgardt, globular cluster parameter database
It is one of the oldest globular clusters known, and one of the poorest in heavy elements.Ying et al. 2023, The Absolute Age of M92NASA, Hubble's Messier Catalog: Messier 92
It holds about 273,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 1073 traced

A globular cluster: tens of thousands of very old stars in a tight ball, orbiting the Milky Way's centre.NASA, Hubble's Messier Catalog: Messier 107NASA, Hubble's Messier Catalog: Messier 92Baumgardt, globular cluster parameter database
Helen Sawyer Hogg added it to Messier's list in 1947; Pierre Méchain had discovered it in 1782.NASA, Hubble's Messier Catalog: Messier 107Steinicke, historical NGC/IC data
It holds about 61,200 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Galactic Globular Cluster Database (parameter table)

Messier 182 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M18NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It lies between the Omega Nebula (M17) and the Sagittarius Star Cloud (M24).Steinicke, historical NGC/IC data; worked out from its numbersNOIRLab image page: M18; worked out from its numbersNASA, Hubble's Messier Catalog: Messier 24

Messier 212 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M21NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It sits just north of the Trifid Nebula (M20), about half a degree away, and is probably between about 5 and 13 million years old.NOIRLab image page: M21; worked out from its numbersSteinicke, historical NGC/IC data; worked out from its numbersHunt & Reffert 2023, A&A (cluster table, VizieR); worked out from its numbersCantat-Gaudin et al. 2020, A&A (table 1, VizieR); worked out from its numbers

Messier 232 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M23Steinicke, historical NGC/IC dataNASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It is a rich cluster in Sagittarius, about the size of the full Moon on the sky.NOIRLab image page: M23

Messier 252 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M25NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It holds the Cepheid variable star U Sagittarii, which brightens and fades every 6.7 days.Riess et al. 2022, Cluster Cepheids with High Precision Gaia ParallaxesSIMBAD: M 25 is IC 4725, and U Sgr is listed as a member of it (Cl* IC 4725)

Messier 262 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M26NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It lies in Scutum, near the Wild Duck Cluster (M11).NOIRLab image page: M26; worked out from its numbersSteinicke, historical NGC/IC data; worked out from its numbers

Messier 292 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M29NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It sits in Cygnus, inside the Milky Way's bright band, dimmed by dust in front of it.NOIRLab image page: M29Hunt & Reffert 2023, A&A (cluster table, VizieR)

Messier 342 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M34NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It is about the size of the full Moon on the sky and visible to the naked eye under dark skies.NOIRLab image page: M34; worked out from its numbers

Messier 362 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M36NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It is the youngest of the three Messier clusters in Auriga (with M37 and M38).NOIRLab image page: M36Hunt & Reffert 2023, A&A (cluster table, VizieR)

Messier 372 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M37NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It is the richest of the three Messier clusters in Auriga.NOIRLab image page: M37Hunt & Reffert 2023, A&A (cluster table, VizieR)

Messier 382 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M38NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
Its brightest stars are often said to trace a cross or the Greek letter pi.NOIRLab image page: M38

Messier 412 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M41NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It sits about 4 degrees south of Sirius and has a combined magnitude of 4.5.Steinicke, historical NGC/IC data; worked out from its numbersHipparcos new reduction, positions via the ESA Gaia archive; worked out from its numbersNOIRLab, Constellation: Canis Major; worked out from its numbers

Messier 462 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M46NASA, Hubble's Messier Catalog: Messier 46NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
The planetary nebula NGC 2438 appears inside it, but is a foreground object, not a member.NASA, Hubble's Messier Catalog: Messier 46

Messier 472 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M47NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It sits beside Messier 46 on the sky, but at about a third of its distance.Hunt & Reffert 2023, A&A (cluster table, VizieR); worked out from its numbersCantat-Gaudin et al. 2020, A&A (table 1, VizieR); worked out from its numbersSteinicke, historical NGC/IC data; worked out from its numbers

Messier 482 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NASA, Hubble's Messier Catalog: Messier 48NOIRLab image page: M48NASA, Hubble's Caldwell Catalog: Caldwell 1
Messier recorded its position wrongly, so it was 'lost' until later astronomers rediscovered it; Bode and Caroline Herschel found it again in the 1780s.NASA, Hubble's Messier Catalog: Messier 48

Messier 502 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M50NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It lies in Monoceros, roughly a third of the way from Sirius to Procyon.NOIRLab image page: M50; worked out from its numbersSteinicke, historical NGC/IC data; worked out from its numbersHipparcos new reduction, positions via the ESA Gaia archive; worked out from its numbers

Messier 522 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M52NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
The Bubble Nebula (NGC 7635) lies just to its south-west on the sky.Steinicke, historical NGC/IC data; worked out from its numbersNOIRLab image page: M52; worked out from its numbers

Messier 672 traced

One of the oldest known open clusters, with stars of about the Sun's age and make-up — a favourite laboratory for studying Sun-like stars.NASA, Hubble's Messier Catalog: Messier 67Önehag et al. 2010, M67-1194, an unusually Sun-like solar twin in M67, arXiv:1009.4579
Its age is usually given as about 4 billion years, unusually old for an open cluster.NASA, Hubble's Messier Catalog: Messier 67

Messier 932 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M93NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It lies in Puppis, low in the sky from northern latitudes.NOIRLab image page: M93; worked out from its numbersSteinicke, historical NGC/IC data; worked out from its numbers

Messier 1032 traced

An open cluster: a family of stars born together from one cloud, slowly drifting apart.NOIRLab image page: M103NASA, Hubble's Messier Catalog: Messier 48NASA, Hubble's Caldwell Catalog: Caldwell 1
It is in Cassiopeia, near the star Ruchbah.NOIRLab image page: M103; worked out from its numbersSteinicke, historical NGC/IC data; worked out from its numbersHipparcos new reduction, positions via the ESA Gaia archive; worked out from its numbers

Messier 393 traced

A large, loose open cluster in Cygnus, quite close to us.NOIRLab image page: M39NASA APOD, 2009 April 12, M39
It is a little larger than the full Moon on the sky and just visible to the naked eye in a dark sky.NASA APOD, 2009 April 12: M39, Open Cluster in Cygnus
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia Collaboration, Babusiaux et al. 2018, A&A 616, A10ESA, How does Gaia study the Milky Way?

The Sagittarius Star Cloud3 traced

A bright patch of the Milky Way where a gap in the dust lets us see deep into the stars of a more distant spiral arm.NASA, Hubble's Messier Catalog: Messier 24NOIRLab image page: M24
It is not a cluster: its stars lie along a deep line of sight, so it has no single distance.NASA, Hubble's Messier Catalog: Messier 24
It spans a few degrees on the sky, several full Moons across.NASA, Hubble's Messier Catalog: Messier 24

Messier 403 traced

A pair of unrelated stars that only look close together; Messier logged it while searching for a nebula reported by Hevelius.NOIRLab image page: M40; worked out from its numbersGaia DR3 (Gaia Collaboration 2023), gaiadr3.gaia_source, ESA Gaia archive
Gaia shows the two stars are at very different distances: about 1,010 and 470 light-years.Gaia DR3 (Gaia Collaboration 2023), gaiadr3.gaia_source, ESA Gaia archive
It is a chance alignment, not an orbiting pair.Merrifield, Gray & Haran 2017, The Observatory 137, 23 (arXiv:1612.00834), Gaia Shows That Messier 40 is Definitely Not a Binary Star

Messier 733 traced

Four stars in a tight little group that only line up by chance: an asterism, not a cluster.Gaia DR3 (Gaia Collaboration 2023), gaiadr3.gaia_source, ESA Gaia archive; worked out from its numbersSteinicke, historical NGC/IC dataNOIRLab image page: M73
Gaia puts its four stars at about 1,030, 1,250, 2,170 and 2,290 light-years — nowhere near each other.Gaia DR3 (Gaia Collaboration 2023), gaiadr3.gaia_source, ESA Gaia archive
It is placed here at its brightest star.Gaia DR3 (Gaia Collaboration 2023), gaiadr3.gaia_source, ESA Gaia archive

De Mairan's Nebula3 traced

A small round cloud of glowing gas just north-east of the Orion Nebula, split from it by a lane of dust.Simon-Diaz et al. 2011, A&A; worked out from its numbersNASA, Hubble's Messier Catalog: Messier 43Steinicke, historical NGC/IC data
It is lit mainly by NU Orionis, a young massive star that is really a four-star system.Aschenbrenner & Przybilla 2024, The quadruple system HD 37061 at the centre of Messier 43Simón-Díaz et al. 2011, A&ANASA, Hubble's Messier Catalog: Messier 43
It is part of the same star-forming cloud as the Orion Nebula.NASA, Hubble's Messier Catalog: Messier 43

The Little Dumbbell Nebula3 traced

The glowing shell thrown off by a dying Sun-like star, its two lobes earning it the name Little Dumbbell.NASA, Hubble's Messier Catalog: Messier 76; worked out from its numbersNASA, Hubble's Messier Catalog: Messier 27NASA, Hubble's Messier Catalog: Messier 46
It is one of the faintest objects in Messier's list.NOIRLab image page, M76NASA Hubble Messier catalog, Messier 76
It was given two NGC numbers because its two lobes looked like separate nebulae.NASA Hubble Messier catalog, Messier 76NOIRLab image page, M76Steinicke, historical NGC/IC data

Messier 323 traced

A small, dense elliptical galaxy in orbit round the Andromeda Galaxy, seen against the outer part of its disc.NASA, Hubble's Messier Catalog: Messier 32Evidence for an outer disk in M32, ApJL 2002, arXiv:astro-ph/0202307
It is the closest example of a compact elliptical galaxy, and the prototype of the class.HST imaging of M32, MNRAS 2023, arXiv:2301.10613Evidence for an outer disk in M32, ApJL 2002, arXiv:astro-ph/0202307
Its centre holds a black hole of a few million times the Sun's mass.van der Marel et al. 1997, Dynamical stability of N-body models for M32, arXiv:astro-ph/9702151van den Bosch & de Zeeuw 2009, Black hole masses in triaxial galaxies (M32 and NGC 3379), arXiv:0910.0844

Messier 1103 traced

A dwarf elliptical galaxy in orbit round the Andromeda Galaxy.NASA, Hubble's Messier Catalog: Messier 110NOIRLab image page: M110
Messier saw it in 1773 but never put it in his list; it was added as M110 in the 1960s.NOIRLab image page, M110NASA Hubble Messier catalog, Messier 110Steinicke, historical NGC/IC data
It holds a few young blue stars, rare in a galaxy of its type.NASA Hubble Messier catalog, Messier 110

Messier 492 traced

A giant elliptical galaxy, the brightest elliptical in the Virgo Cluster.Janowiecki et al. 2010, Diffuse tidal structures in the halos of Virgo ellipticalsNOIRLab image page: M59NASA, Hubble's Messier Catalog: Messier 49The ACS Virgo Cluster Survey I (Cote et al. 2004)
It was the first member of the Virgo Cluster to be found, by Messier in 1771.NASA Hubble Messier catalog, Messier 49Steinicke, historical NGC/IC data

Messier 582 traced

A barred spiral galaxy in the Virgo Cluster, among the brightest galaxies in the constellation Virgo.NASA, Hubble's Messier Catalog: Messier 58NOIRLab image page: M58
Its centre is an active nucleus fed by gas falling onto a black hole.Dewangan et al. 2004, Iron K-alpha in M81 and NGC 4579, arXiv:astro-ph/0402327 (Astrophys.J. 607 (2004) 788-793)Terashima et al. 2000, Iron K line variability in NGC 4579, arXiv:astro-ph/0006055NASA Hubble Messier catalog, Messier 58

Messier 592 traced

An elliptical galaxy in the Virgo Cluster.NASA, Hubble's Messier Catalog: Messier 59NOIRLab image page: M59
It lies less than half a degree from Messier 60 on the sky.Steinicke, historical NGC/IC data; worked out from its numbersNASA Hubble Messier catalog, Messier 59

Messier 603 traced

A giant elliptical galaxy in the Virgo Cluster, paired on the sky with the spiral NGC 4647.NASA, Hubble's Messier Catalog: Messier 60Shen & Gebhardt 2010, The Supermassive Black Hole and Dark Matter Halo of NGC 4649 (M60), arXiv:0910.4168 (Astrophys.J.711:484-494,2010)NOIRLab image page: M59
Its central black hole is among the most massive measured, a few billion times the Sun's mass.NASA Hubble Messier catalog, Messier 60
With NGC 4647 it is listed as Arp 116.NASA Hubble Messier catalog, Messier 60

Messier 612 traced

A face-on barred spiral galaxy in the Virgo Cluster.NASA, Hubble's Messier Catalog: Messier 61NOIRLab image page: M61
It has hosted several supernovae seen from Earth.NASA Hubble Messier catalog, Messier 61

The Sunflower Galaxy2 traced

A flocculent spiral galaxy, its many short, patchy arms winding round a yellow core; also called the Sunflower Galaxy.NASA, Hubble's Messier Catalog: Messier 63NOIRLab image page: M63
It belongs to the same group of galaxies as the Whirlpool Galaxy (M51).J-PLUS spatially resolved study II: the M51 group, A&A 2026, arXiv:2603.15869

The Black Eye Galaxy2 traced

A spiral galaxy with a dark band of dust across its bright centre, like a black eye.NASA, Hubble's Messier Catalog: Messier 64NOIRLab image page: M64
Its outer gas spins the opposite way to its inner gas, probably the trace of a merger with a smaller galaxy.NASA Hubble Messier catalog, Messier 64

Messier 652 traced

A spiral galaxy, one of the Leo Triplet.NASA, Hubble's Messier Catalog: Messier 65NOIRLab image page: M65
It, Messier 66 and NGC 3628 form the Leo Triplet, three spirals in one telescope field.NASA Hubble Messier catalog, Messier 65NASA APOD, 2012 Jul 6, The Tidal Tail of NGC 3628

Messier 662 traced

A spiral galaxy in the Leo Triplet, its arms pulled out of shape by its neighbours.NASA, Hubble's Messier Catalog: Messier 66
Several supernovae have been seen in it.SN 2009hd in NGC 3627 (M66), arXiv:1108.2645

The Phantom Galaxy3 traced

A grand-design spiral galaxy seen face-on, its arms dotted with clusters of young stars.NASA, Hubble's Messier Catalog: Messier 74ESA/Webb Picture of the Month, Webb Inspects the Heart of the Phantom Galaxy
It is one of the hardest Messier objects to see, because of its low surface brightness.NASA Hubble Messier catalog, Messier 74
The James Webb Space Telescope imaged its filaments of gas and dust in 2022.ESA/Webb Picture of the Month, Webb Inspects the Heart of the Phantom GalaxyESA, Webb inspects the heart of the Phantom Galaxy

Messier 773 traced

A spiral galaxy with an intensely bright, active core: one of the nearest Seyfert galaxies.NASA, Hubble's Messier Catalog: Messier 77NOIRLab image page: M77Steinicke, historical NGC/IC data
It is one of the six galaxies Carl Seyfert described in 1943, the first of the class named after him.Shields 1999, A Brief History of AGN, arXiv:astro-ph/9903401
Its active nucleus is fed by gas falling onto a supermassive black hole, partly hidden by dust.ESO press release eso2203NASA Hubble Messier catalog, Messier 77

The Southern Pinwheel Galaxy2 traced

A bright, relatively nearby spiral galaxy, full of star-forming regions.NASA, Hubble's Messier Catalog: Messier 83Stockdale et al. 2006, Historical supernovae in M83, arXiv:astro-ph/0511202 (Astron.J.131:889-894,2006)
Six supernovae have been seen in it during the 20th century.Stockdale et al. 2006, Historical supernovae in M83, arXiv:astro-ph/0511202 (Astron.J.131:889-894,2006)Blair et al. 2014, A newly recognized very young SNR in M83, arXiv:1501.00030

Messier 842 traced

A large elliptical or lenticular galaxy at the heart of the Virgo Cluster.NASA, Hubble's Messier Catalog: Messier 84NOIRLab image page: M84NASA APOD, 2006 Oct 11, Markarian's Chain of Galaxies
It is at the western end of Markarian's Chain, a curved line of galaxies near the heart of the Virgo Cluster.NASA APOD, 2006 Oct 11, Markarian's Chain of GalaxiesSteinicke, historical NGC/IC data; worked out from its numbers

Messier 852 traced

A lenticular galaxy on the northern edge of the Virgo Cluster.NOIRLab image page: M85NASA, Hubble's Messier Catalog: Messier 85
It lies in Coma Berenices, the most northerly of the Virgo Cluster's Messier galaxies.NOIRLab image page, M85NASA Hubble Messier catalog, Messier 85

Messier 862 traced

A large elliptical or lenticular galaxy in the Virgo Cluster, falling through it at high speed.NASA, Hubble's Messier Catalog: Messier 86NASA APOD, 2006 Oct 11, Markarian's Chain of Galaxies
It is part of Markarian's Chain, next to Messier 84 on the sky.NASA APOD, 2006 Oct 11, Markarian's Chain of GalaxiesNASA Hubble Messier catalog, Messier 86

Messier 882 traced

A spiral galaxy in the Virgo Cluster.NASA, Hubble's Messier Catalog: Messier 88NOIRLab image page: M88Pre-peak ram pressure stripping in NGC 4501, A&A 2008, arXiv:0801.4874
Gas is being stripped from it as it moves through the cluster's hot gas.Pre-peak ram pressure stripping in NGC 4501, A&A 2008, arXiv:0801.4874

Messier 892 traced

An elliptical galaxy in the Virgo Cluster that looks almost perfectly round.NASA, Hubble's Messier Catalog: Messier 89NOIRLab image page: M89
Faint shells and plumes around it are the leftovers of smaller galaxies it swallowed.Janowiecki et al. 2010, Diffuse Tidal Structures in the Halos of Virgo Ellipticals, arXiv:1004.1473

Messier 902 traced

A spiral galaxy in the Virgo Cluster that has been stripped of much of its gas, so it makes few new stars.NASA, Hubble's Messier Catalog: Messier 90
Its arms hold very little star formation, because much of its gas has been stripped away.NASA Hubble Messier catalog, Messier 90

Messier 912 traced

A barred spiral galaxy in the Virgo Cluster.NOIRLab image page: M91NASA, Hubble's Messier Catalog: Messier 91
Long considered Messier's "lost" object, it is now identified with NGC 4548.NOIRLab image page, M91Steinicke, historical NGC/IC data

Messier 942 traced

A spiral galaxy with a bright inner ring of new stars round its core.NASA, Hubble's Messier Catalog: Messier 94NOIRLab image page: M94
Its bright ring is a band of intense star formation.NASA Hubble Messier catalog, Messier 94

Messier 952 traced

A barred spiral galaxy in Leo.NASA, Hubble's Messier Catalog: Messier 95NOIRLab image page: M95
It belongs to the Leo I group, with Messier 96 and Messier 105.NASA Hubble Messier catalog, Messier 95NASA Hubble Messier catalog, Messier 105

Messier 962 traced

A spiral galaxy, one of the two brightest members of the Leo I group.NOIRLab image page: M96NOIRLab image page: M105NASA, Hubble's Messier Catalog: Messier 96
Its arms and core are slightly lopsided, probably pulled by its neighbours.NASA Hubble Messier catalog, Messier 96

Messier 982 traced

A spiral galaxy seen nearly edge-on, in the Virgo Cluster.NOIRLab image page: M98NASA, Hubble's Messier Catalog: Messier 98
It is moving towards us even though it is in a cluster tens of millions of light-years away.NASA Hubble Messier catalog, Messier 98

Messier 992 traced

A face-on spiral galaxy in the Virgo Cluster with a strikingly lopsided spiral pattern.NOIRLab image page: M99Haynes et al. 2007, NGC 4254: An Act of Harassment
Lord Rosse saw its spiral form in the 1840s, among the first galaxies seen to be spirals.NOIRLab image page, M99Steinicke, historical NGC/IC data

Messier 1002 traced

A grand-design spiral galaxy in the Virgo Cluster, one of the brighter galaxies in it.NASA, Hubble's Messier Catalog: Messier 100NOIRLab image page: M100
Hubble's measurements of its Cepheid stars in the 1990s helped pin down the expansion rate of the Universe.Narasimha & Mazumdar 1998, Cepheid Distance to M100 in Virgo Cluster, arXiv:astro-ph/9803195NASA Hubble Messier catalog, Messier 100

Messier 1022 traced

A lenticular galaxy seen edge-on, a thin disc split by a sharp lane of dust; usually identified as Messier 102.NOIRLab image page: M102NASA, Hubble's Messier Catalog: Messier 102Steinicke, historical NGC/IC data
Which object Messier meant by M102 is still argued over; NGC 5866 is the usual answer.NOIRLab image page, M102Steinicke, historical NGC/IC data

Messier 1052 traced

An elliptical galaxy in the Leo I group.NASA, Hubble's Messier Catalog: Messier 105NOIRLab image page: M105
It is a standard example of an ordinary elliptical galaxy, used as a reference for measuring others.Thomsen et al. 1997, Distance to Coma from SBF, arXiv:astro-ph/9704121

Messier 1063 traced

A spiral galaxy with an active core, whose orbiting water masers give a precise geometric distance, an anchor of the cosmic distance ladder.An Improved Distance to NGC 4258, 2019, arXiv:1908.05625; worked out from its numbersHumphreys et al. 2013, Toward a New Geometric Distance to NGC 4258 III, arXiv:1307.6031NOIRLab image page: M106
Water masers orbiting its central black hole weigh it at about 40 million times the Sun's mass.An Improved Distance to NGC 4258, 2019, arXiv:1908.05625Humphreys et al. 2013, Toward a New Geometric Distance to NGC 4258 III, arXiv:1307.6031
It is used as an anchor for the cosmic distance ladder.Humphreys et al. 2013, Toward a New Geometric Distance to NGC 4258 III, arXiv:1307.6031An Improved Distance to NGC 4258, 2019, arXiv:1908.05625

The Surfboard Galaxy2 traced

A barred spiral galaxy seen almost edge-on, near the Owl Nebula on the sky.NASA, Hubble's Messier Catalog: Messier 108; worked out from its numbersSteinicke, historical NGC/IC data
It shows no bright central bulge, with dust and star-forming knots across its disc.NOIRLab image page, M108NASA Hubble Messier catalog, Messier 108

Messier 1092 traced

A barred spiral galaxy in Ursa Major, near the star Phecda on the sky.NASA, Hubble's Messier Catalog: Messier 109NOIRLab image page: M109
It has three satellite galaxies of its own.NASA Hubble Messier catalog, Messier 109

The Sculptor Galaxy3 traced

A big, dusty spiral seen almost edge-on, forming stars at a furious rate: a starburst galaxy.ESO press release eso1025NASA, Hubble's Caldwell Catalog: Caldwell 65
Caroline Herschel discovered it in 1783.Steinicke, historical NGC/IC dataNASA Hubble Caldwell catalog, Caldwell 65ESO press release eso1025
It is the brightest member of the Sculptor Group, one of the nearest groups of galaxies to ours.ESO press release eso1025

NGC 552 traced

An irregular galaxy much like the Large Magellanic Cloud, seen almost edge-on.Gas and dark matter in the Sculptor group: NGC 55, MNRAS 2013, arXiv:1307.2962NASA, Hubble's Caldwell Catalog: Caldwell 72
With NGC 300, it is one of the two nearest large members of the Sculptor Group.Gas and dark matter in the Sculptor group: NGC 55, MNRAS 2013, arXiv:1307.2962Pietrzynski et al. 2006, Araucaria Project, distance to NGC 55, arXiv:astro-ph/0610595 (Astron.J.132:2556-2565,2006)

NGC 3002 traced

A nearly face-on spiral galaxy in the Sculptor Group.NASA Hubble, Caldwell 70Pietrzynski et al. 2006, Araucaria project, arXiv:astro-ph/0610595 (Astron.J.132:2556-2565,2006)
Its Cepheid stars have been used to check the distance scale to nearby galaxies.Gieren et al. 2004, Araucaria Project, improved distance to NGC 300, arXiv:astro-ph/0405581

The Needle Galaxy2 traced

A spiral galaxy seen almost perfectly edge-on, a thin streak of light crossed by a dark lane of dust.NASA Hubble, Caldwell 38
It is one of the most famous edge-on galaxies in the sky.ESA/Hubble Picture of the Week potw1228a

NGC 8912 traced

An edge-on spiral galaxy thought to look much like the Milky Way would from outside.NASA Hubble, Caldwell 23
Filaments of dust rise far above and below its disc.NASA Hubble Caldwell catalog, Caldwell 23Howk & Savage 1997, Extraplanar Dust in the Edge-On Spiral NGC 891, arXiv:astro-ph/9709197 (Astron.J.114:2463-2478,1997)

The Fireworks Galaxy2 traced

A spiral galaxy, obscured by the Milky Way's dust, that has produced an unusual number of supernovae.NASA Hubble, Caldwell 12arXiv:1903.00173
Ten supernovae have been seen in it since 1917, for years the most known in any one galaxy.NASA Hubble Caldwell catalog, Caldwell 12Anderson & Soto 2012, On the multiplicity of supernovae within host galaxies, arXiv:1212.4153Gemini Observatory, Galactic Fireworks release

NGC 73312 traced

A large spiral galaxy in Pegasus, often called a twin of the Milky Way.NASA Hubble, Caldwell 30
It is the dominant galaxy of the Deer Lick Group, a chance grouping on the sky: the small galaxies beside it lie far behind it.NASA APOD, 2014 Dec 18, NGC 7331 and BeyondFort Lewis College Observatory, NGC 7331Steinicke, historical NGC/IC data

The Whale Galaxy2 traced

An edge-on spiral galaxy, slightly bent, shaped like a whale on the sky.NASA APOD 2004 Jan 23NASA APOD 2010 May 17NASA Hubble, Caldwell 32
It is interacting with a smaller galaxy, NGC 4627, next to it.Martinez-Delgado et al. 2014, Discovery of a stellar tidal stream around NGC 4631, arXiv:1410.6368Wang et al. 2023, FEASTS: HI around NGC 4631, arXiv:2301.00937

NGC 24032 traced

A spiral galaxy in the M81 group, full of star-forming regions.NASA Hubble, Caldwell 7Kennicutt et al. 2003, arXiv:astro-ph/0305437 (Publ.Astron.Soc.Pac.115:928-952,2003)
It was one of the first galaxies beyond the Local Group in which Cepheid stars were found.Tammann & Reindl 2012, Allan Sandage and the Distance Scale, arXiv:1211.4655

The Hidden Galaxy2 traced

A large face-on spiral galaxy almost hidden behind the dust and stars of the Milky Way's disc.NASA Hubble, Caldwell 5Makarov et al. 2014, HyperLEDA distance catalogue, arXiv:1408.3476
It would be one of the brightest galaxies in the sky if our galaxy's dust were not in the way.NASA Hubble Caldwell catalog, Caldwell 5ESA/Hubble Picture of the Week potw1727a

Barnard's Galaxy3 traced

A dwarf irregular galaxy in the Local Group, a member of our own family of galaxies.NASA Hubble, Caldwell 57The rotation of the halo of NGC 6822, arXiv:1605.05582
E. E. Barnard discovered it in 1884.Steinicke, historical NGC/IC dataNASA Hubble Caldwell catalog, Caldwell 57
Edwin Hubble's 1925 study of its Cepheid stars helped show that such objects are galaxies far beyond the Milky Way.Rotation of the halo of NGC 6822, arXiv:1605.05582Hutchings et al. 1999, Resolved outer population of NGC 6822, arXiv:astro-ph/9903245NASA Hubble Caldwell catalog, Caldwell 57

IC 16132 traced

A faint dwarf irregular galaxy in the Local Group.NASA Hubble, Caldwell 51
It holds very little dust, so its stars can be seen with unusual clarity.ESO press release eso1603NASA Hubble Caldwell catalog, Caldwell 51

The Hamburger Galaxy2 traced

An edge-on spiral galaxy in the Leo Triplet, with a warped disc and a long tidal tail.NOIRLab, Edge-on Spiral Galaxy NGC 3628NASA APOD 2012 Jul 6
A tail of stars about 300,000 light-years long trails from it, pulled out by its neighbours.NASA APOD, 2012 Jul 6, The Tidal Tail of NGC 3628

The Antennae Galaxies3 traced

Two spiral galaxies in the middle of colliding, their merger setting off bursts of star formation.NASA Hubble, Caldwell 60/61
Two long tails of stars thrown out by the collision stretch far from them.Whitmore et al. 2010, The Antennae Galaxies Revisited, arXiv:1005.0629NASA Hubble Caldwell catalog, Caldwell 60/61
They are one of the nearest and best-studied galaxy mergers.Whitmore et al. 2010, The Antennae Galaxies Revisited, arXiv:1005.0629ESA/Hubble release heic0812

NGC 67523 traced

A bright globular cluster in Pavo.NASA Hubble, Caldwell 93ESO eso1323
It holds about 261,000 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Globular cluster database, parameter table
Its core has collapsed into a dense bright centre.Thomson et al. 2012, A multi-wavelength survey of NGC 6752, arXiv:1204.4723Corongiu et al. 2024, Timing of millisecond pulsars in NGC 6752 III, ApJ 972, 198, arXiv:2407.03271Ferraro et al. 2003, Dynamical status of the core of NGC 6752, arXiv:astro-ph/0306138 (Astrophys.J. 595 (2003) 179-186)

NGC 63973 traced

One of the two nearest globular clusters to the Sun, in Ara.Baumgardt & Vasiliev 2021, arXiv:2105.09526Richer et al. 2007, Deep ACS Imaging in NGC 6397, arXiv:0708.4030NASA Hubble, Caldwell 86
Its nearness lets telescopes see its faintest white dwarfs and red dwarfs.ESA/Hubble release heic0608NASA Hubble Caldwell catalog, Caldwell 86
It holds about 82,400 times the Sun's mass in stars (Baumgardt's globular cluster database).Baumgardt, Globular cluster database, parameter table

The Saturn Nebula3 traced

A planetary nebula with two thin extensions on either side, which made it look like Saturn in early telescope views.NASA Hubble, Caldwell 55ESA, Saturn Nebula (NGC 7009)
William Herschel discovered it in 1782.Steinicke, historical NGC/IC dataNASA Hubble, Caldwell 55ESA, Saturn Nebula (NGC 7009)
At magnitude 8 it looks like a star in a small telescope; larger ones show the two lobes either side that recall Saturn's rings.NASA Science, Caldwell 55 (the Saturn Nebula)

The Blinking Planetary3 traced

A planetary nebula whose bright central star overwhelms the faint shell when looked at directly, so it seems to blink on and off.NASA Hubble, Caldwell 15
The blinking is a trick of the eye, not of the nebula.NASA Hubble, Caldwell 15
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 2135352396915239808: parallax 0.7714 ± 0.0359 mas (central star of NGC 6826)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Blue Snowball Nebula3 traced

A small, bright planetary nebula in Andromeda, nicknamed the Blue Snowball.NASA Hubble, Caldwell 22Guerrero et al. 2004, NGC 7662 shell study, arXiv:astro-ph/0407029
Its blue-green colour comes mostly from oxygen lit by the hot white dwarf at its centre.Martz-Kohl Observatory DSO catalogue, Caldwell 22 (Blue Snowball)NASA Science, Caldwell 22
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 1924818288379268736: parallax 0.5690 ± 0.0334 mas (central star of NGC 7662)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

NGC 23924 traced

A planetary nebula whose outer ring of filaments looks like a face in a fur hood.NASA APOD 2000 Jan 24NASA Hubble, Caldwell 39
NASA dropped an older nickname for it in 2020 and uses its official name, NGC 2392.NASA, NASA to Reexamine Nicknames for Cosmic Objects (2020)
William Herschel discovered it in 1787.Steinicke, historical NGC/IC dataNASA Hubble, Caldwell 39
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 865037169677723904: parallax 0.5451 ± 0.0467 mas (central star of NGC 2392)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Ghost of Jupiter3 traced

A planetary nebula about the apparent size of Jupiter, in Hydra.NASA Hubble, Caldwell 59
William Herschel discovered it in 1785.Steinicke, historical NGC/IC dataNASA Hubble, Caldwell 59
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 5668874905325843456: parallax 0.7452 ± 0.0502 mas (central star of NGC 3242)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Butterfly Nebula3 traced

A planetary nebula with two vast wings of gas streaming out from a dusty waist.ESA/Webb weic2517NASA, Hubble Opens New Eyes on the Universe
Its central star, at about 220,000 kelvin, is one of the hottest known central stars of a planetary nebula in our galaxy.ESA, Webb investigates complex heart of a cosmic butterflyMatsuura et al. 2025, MNRAS 542
A thick ring of dust hides the central star from direct view.ESA, Webb investigates complex heart of a cosmic butterflyMatsuura et al. 2025, MNRAS 542

NGC 70273 traced

A young, dense planetary nebula in Cygnus.HeH+ detection, Nature 2019, arXiv:1904.09581Steinicke, historical NGC/IC data
In 2019 astronomers reported the first detection in space of the helium hydride ion, which formed the Universe's first molecular bond, here.Güsten et al. 2019, Nature 568, 357Güsten et al. 2019, full text
Its distance, about 3,200 light-years, is measured from the nebula's own expansion over 25 years of radio monitoring. Gaia's parallax of its central star is unreliable here: the bright, compact nebula spoils it.Zijlstra, van Hoof & Perley 2008, ApJ: "A distance of 980+-100 pc is derived" (full text)Zijlstra, van Hoof & Perley 2008, ApJ (journal)Chornay & Walton 2021: its Gaia source has RUWE 2.56; "for compact PNe Gaia may not detect the CSPN"Stanghellini, Shaw & Villaver 2008: statistical distances do not work well for bipolar nebulae

The Spirograph Nebula2 traced

A planetary nebula in Lepus, known as the Spirograph Nebula, with remarkable textures weaving through it.ESA/Hubble opo0028aESA, Spirograph Nebula (IC 418)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 2985789113026163584: parallax 0.7341 ± 0.0290 mas (central star of IC 418)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

NGC 24403 traced

A planetary nebula in Puppis with a chaotic structure and two bowtie-shaped lobes.NASA, Hubble Views a Colorful Demise of a Sun-like Star
Its central white dwarf is one of the hottest known.NASA, Hubble Views a Colorful Demise of a Sun-like Star
Its distance is a statistical estimate, uncertain by about 20%.Stanghellini & Haywood 2010, ApJ 714, 1096Stanghellini & Haywood 2010, the same paper free to read (arXiv)Stanghellini, Shaw & Villaver 2008, ApJ (VizieR J/ApJ/689/194)Stanghellini & Haywood 2010, full text: "a rather conservative uncertainty of ±20%"

The Little Ghost Nebula3 traced

A small ring-shaped planetary nebula in Ophiuchus.ESA/Hubble opo0225aRamos-Larios et al. 2011, arXiv:1111.1474Steinicke, historical NGC/IC data
Its central star is a Wolf–Rayet-type star, stripped of hydrogen.Monteiro et al. 2004, ApJ 609, 194Monteiro et al. 2004, the same paper free to read (arXiv)Werner & Herwig 2006, PASP 118, 183Werner & Herwig 2006, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 4111368477921050368: parallax 0.9184 ± 0.0494 mas (central star of NGC 6369)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

NGC 2463 traced

A planetary nebula in Cetus whose central star is one of a triple star system.Adam & Mugrauer 2014, HIP 3678 hierarchical triple, arXiv:1409.5339NASA Hubble, Caldwell 56
Its central star is a very hot PG 1159-type star, between a giant and a white dwarf.Werner & Herwig 2006, PASP 118, 183Werner & Herwig 2006, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 2376592910265354368: parallax 1.7993 ± 0.0786 mas (central star of NGC 246)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

NGC 23463 traced

A butterfly-shaped planetary nebula around a close pair of stars.ESA/Hubble opo9935dNASA, Butterfly Wing-Shaped Planetary Nebula NGC 2346
Its central binary may have shaped the nebula's two lobes.ESA/Hubble, NGC 2346 (opo9935d)NASA, Butterfly Wing-Shaped Planetary Nebula NGC 2346
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 3109444657456300288: parallax 0.7223 ± 0.0179 mas (central star of NGC 2346)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Heart Nebula2 traced

A large heart-shaped cloud of glowing hydrogen in Cassiopeia, lit by the young cluster at its centre.NASA APOD 2025 Oct 21NOIRLab, Open Cluster IC 1805
The cluster at its heart, Melotte 15, holds stars many times the Sun's mass.Panwar et al. 2017, MNRASPanwar et al. 2017, the same paper free to read (arXiv)NASA APOD 2017 Feb 10, Melotte 15 in the Heart

The Soul Nebula2 traced

A large star-forming nebula beside the Heart Nebula.NASA, WISE Sees the Heart and Soul Nebulae
It and the Heart Nebula are part of one huge star-forming complex.NASA, WISE Sees the Heart and Soul NebulaeLim et al., MNRAS (IC 1848 in W5 West)Lim et al. 2013, the same paper free to read (arXiv)

The Pelican Nebula2 traced

A glowing cloud next to the North America Nebula, shaped like a pelican.NASA/Spitzer ssc2011-03bNOIRLab, The Pelican Nebula (IC 5070)
It is part of the same cloud as the North America Nebula, split from it by a lane of dark dust.Bally et al. 2014, AJ 148, 120Bally et al. 2014, the same paper free to read (arXiv)

The Bubble Nebula3 traced

A bubble of gas blown by the wind of one massive young star.ESA/Hubble heic1608Bubble Nebula multi-wavelength study, arXiv:2003.06371
Its star, BD+60 2522, is a hot O-type star many times the Sun's mass.Toalá et al. 2020, MNRASToalá et al. 2020, the same paper free to read (arXiv)NASA Hubble, Caldwell 11
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 2014149897293278848: parallax 0.3341 ± 0.0152 mas (BD+60 2522)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Crescent Nebula3 traced

A shell of gas shaped by the fierce wind of the Wolf–Rayet star WR 136 at its centre.NASA Hubble, Caldwell 27
WR 136 is near the end of its life and has already shed its outer layers.NASA Hubble, Caldwell 27
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 2061690233159124352: parallax 0.5772 ± 0.0160 mas (WR 136)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Christmas Tree Cluster and Cone Nebula2 traced

A young star cluster in Monoceros wrapped in glowing gas, with the dark Cone Nebula pointing at it from the south.Dahm 2008, arXiv:0808.3835NASA APOD 2016 Dec 24
Its dominant star, S Monocerotis, sits near the base of the 'tree'.NASA APOD 2016 Dec 24, Fox Fur, a Unicorn, and a Christmas TreeDahm 2008, Handbook of Star Forming Regions Vol. I

The Elephant's Trunk Nebula3 traced

A huge glowing region in Cepheus, with a dense, elongated cloud of gas — the Elephant's Trunk — inside it.NOIRLab, IC1396, The Elephant Trunk NebulaSubaru HSC observations of IC 1396, arXiv:2503.16205
It is lit mostly by one massive star system, HD 206267.Kun, Kiss & Balog 2008, Handbook of Star Forming Regions Vol. I
Its distance comes from where stars behind it start to look dimmed and reddened by its dust, measured with Gaia.Zucker et al. 2020, A&A 633, A51Zucker et al. 2020, full text

The Pacman Nebula2 traced

A star-forming nebula in Cassiopeia, nicknamed Pacman for its overall shape.NASA APOD 2011 Aug 25NASA APOD 2005 Aug 23
Its young cluster is IC 1590.Sharma et al. 2012, PASJSharma et al. 2012, the same paper free to read (arXiv)

The Cat's Paw Nebula3 traced

One of the most active nurseries of massive stars in the Milky Way, in Scorpius.ESO eso1003
It is forming stars, many of them massive, at a high rate.ESO, eso1003Tigé et al. 2017, A&A 602, A77Tigé et al. 2017, the same paper free to read (arXiv)
Its glowing gas clouds look like the print of a cat's paw.ESO, eso1003

The War and Peace Nebula2 traced

A large star-forming region in Scorpius around the cluster Pismis 24, one of the richest in very massive stars.ESA/Hubble heic0619ESO eso1226arXiv:astro-ph/0612012
Pismis 24 holds stars of about 100 times the Sun's mass, among the more massive on record.NASA APOD 2006 Dec 19, Massive Stars in Open Cluster Pismis 24NASA, Heavyweight Stars Light Up Nebula NGC 6357Maíz Apellániz et al. 2007, ApJMaíz Apellániz et al. 2007, the same paper free to read (arXiv)

The Running Chicken Nebula3 traced

A glowing nebula in Centaurus dotted with small dark clouds called Thackeray's globules.ESO eso1135
Thackeray's globules are dense clumps of dust silhouetted against the glow.Fernández-López et al. 2025, MNRAS (Thackeray's globules)ESO, eso1135
It is lit by the hot young stars of the cluster Collinder 249.Fernández-López et al. 2025, MNRAS (Thackeray's globules)ESO, eso2320

Thor's Helmet3 traced

A helmet-shaped bubble of gas blown by the wind of the Wolf–Rayet star WR 7.ESO eso1238Zhekov 2014, arXiv:1406.2463
WR 7 is a massive star that has lost much of its outer hydrogen; about a fifth of its surface is still hydrogen by mass.Hamann, Gräfener & Liermann 2006, A&AHamann et al. 2019, A&A 625, A57
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 archive, gaiadr3.gaia_source 3032940844556081408: parallax 0.2096 ± 0.0268 mas (WR 7)Gaia Collaboration 2023, A&A 674, A1 (Gaia DR3)

The Cocoon Nebula2 traced

A small glowing nebula in Cygnus at the end of a long dark lane of dust.NASA APOD 2022 Oct 26
The dark lane Barnard 168 trails away from it like a tail.NASA APOD 2011 Aug 19, Herschel's CocoonNASA APOD 2026 Sep 21, Cocoon Nebula Wide Field

The Running Man Nebula3 traced

A blue reflection nebula just north of the Orion Nebula, where dark dust lanes trace a running figure.NASA APOD 2007 Dec 20Peterson & Megeath 2008, arXiv:0809.4006
It is part of the Orion star-forming complex.Peterson & Megeath 2008, Handbook of Star Forming Regions Vol. I
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Cantat-Gaudin et al. 2020, A&A 640, A1, cluster tableCantat-Gaudin et al. 2020, the same paper free to read (arXiv)

NGC 13333 traced

A reflection nebula in Perseus hiding a nest of newborn stars inside the Perseus molecular cloud.Steinicke, historical NGC/IC dataGutermuth et al., arXiv:0710.1860Luhman et al. 2016, ApJ 827, 52
Infrared telescopes find well over a hundred very young stars in it.Gutermuth et al. 2008, ApJGutermuth et al. 2008, the same paper free to read (arXiv)Luhman et al. 2016, ApJ 827, 52Luhman et al. 2016, the same paper free to read (arXiv)
It lies in the Perseus molecular cloud, one of the nearest star-forming clouds to the Sun.Luhman et al. 2016, ApJ 827, 52Luhman et al. 2016, the same paper free to read (arXiv)

Hubble's Variable Nebula3 traced

A fan of dust lit by the young star R Monocerotis; the fan changes in brightness and shape over weeks.NASA Hubble, Caldwell 46
It was the first object photographed with the Palomar 200-inch telescope, in 1949.Caltech, A History of Palomar ObservatoryCaltech Archives, Hubble's Variable Nebula, 26 Jan 1949
Edwin Hubble studied its changes, hence the name.NASA Hubble, Caldwell 46Lightfoot et al. 2025 (Hubble's Variable Nebula I)

The Pipe Nebula3 traced

A dark cloud of dust in Ophiuchus shaped like a smoker's pipe, blotting out the stars of the Milky Way behind it.NASA APOD 2020 Aug 7ESO eso1233
It forms part of the Dark Horse, a larger shape of dark clouds.British Astronomical Association, Sky notes for 2023 June & July (N. Hewitt)
The Snake Nebula lies close to it on the sky; the dark globule Barnard 68 is also in Ophiuchus.NOIRLab image noao-snakemcquillan, Snake Nebula (caption read via the AstroPix mirror; noirlab.edu rendered empty)NASA APOD 2005 May 21, Snake in the DarkNASA APOD 2012 November 23, The Pipe NebulaNASA APOD 2017 October 8, Dark Molecular Cloud Barnard 68ESO, The Pipe Nebula (image yb)

The Taurus Molecular Cloud3 traced

A large complex of nearby dark clouds where low-mass stars are forming.Kenyon, Gomez & Whitney 2008, arXiv:0810.1298
T Tauri, the prototype of young Sun-like stars, lies in it.Kenyon, Gómez & Whitney 2008, Handbook of Star Forming Regions Vol. I
Its distance comes from where stars behind it start to look dimmed and reddened by its dust, measured with Gaia.Zucker et al. 2020, A&A 633, A51Zucker et al. 2020, full text

The Chamaeleon Clouds3 traced

A group of dark clouds in the far southern sky that are forming young stars and brown dwarfs.Luhman 2007, arXiv:0710.3037; worked out from its numbers
It is one of the nearest star-forming regions to the Sun.Luhman 2007, ApJS 173, 104Luhman 2007, the same paper free to read (arXiv)
Its distance comes from where stars behind it start to look dimmed and reddened by its dust, measured with Gaia.Zucker et al. 2020, A&A 633, A51Zucker et al. 2020, full text

The Lupus Clouds3 traced

A group of clouds in Lupus that are forming young stars.ALMA Lupus disk survey, arXiv:1604.05719
Its young stars still have discs of dust and gas, where planets may form.Ansdell et al. 2016, ApJ 828, 46Ansdell et al. 2016, the same paper free to read (arXiv)
Its distance comes from where stars behind it start to look dimmed and reddened by its dust, measured with Gaia.Zucker et al. 2020, A&A 633, A51Zucker et al. 2020, full text

The Corona Australis Cloud3 traced

A nearby dark cloud forming young stars around the variable star R Coronae Australis.Neuhauser & Forbrich 2008, arXiv:0808.3374ESO eso1027
It is one of the closest regions of active star formation to the Sun.Neuhäuser & Forbrich 2008, Handbook of Star Forming Regions Vol. II
Its distance comes from where stars behind it start to look dimmed and reddened by its dust, measured with Gaia.Zucker et al. 2020, A&A 633, A51Zucker et al. 2020, full text

The Aquila Rift3 traced

Part of the Great Rift — the dark lanes of dust that split the bright band of the Milky Way from Cygnus to Sagittarius.NASA APOD 1996 May 15, The Milky Way Near the Northern CrossNASA APOD 2022 October 29, LDN 673: Dark Clouds in AquilaNASA/JPL Night Sky Network, Night Sky Notes (Great Rift)Straižys et al. 2003, full text: the Milky Way splits into two branches; "usually is called the Aquila Rift"
It is one of the nearby large cloud complexes, about 200 to 300 parsecs away.Levshakov et al. 2013, A&AStraižys et al. 2003, A&A 405, 585Straižys et al. 2003, the same paper free to read (arXiv)Könyves et al. 2015, A&A 584, A91Zucker et al. 2020, A&A 633, A51Zucker et al. 2020, the same paper free to read (arXiv)
Its distance comes from where stars behind it start to look dimmed and reddened by its dust, using Gaia parallaxes with sky-survey colours.Zucker et al. 2020, A&A 633, A51

The Wishing Well Cluster2 traced

A big, bright open cluster in Carina, easily seen with the naked eye.ESO eso1439Steinicke, historical NGC/IC data
It was the first target observed by the Hubble Space Telescope, in May 1990.ESO release eso1439

The Southern Beehive2 traced

A rich, naked-eye open cluster in Carina.NASA Hubble, Caldwell 96van Leeuwen 2009, arXiv:0902.1039
Its nickname comes from its likeness to the northern Beehive Cluster (M44).NASA Science, Caldwell 96NASA Science, Messier 44

The Owl Cluster2 traced

An open cluster in Cassiopeia.Steinicke, historical NGC/IC data
Whether its brightest 'eye', Phi Cassiopeiae, belongs to the cluster is unsettled: its distance fits, but its motion does not clearly agree.Kasikov et al. 2026, arXiv:2602.02449 (A&A 708, A78 (2026))

Caroline's Rose2 traced

A rich open cluster about a billion years old, in Cassiopeia.Steinicke, historical NGC/IC dataStanghellini & Haywood 2010, open-cluster age table, arXiv:1003.0759
Caroline Herschel discovered it in 1783.Steinicke, historical NGC/IC data

NGC 62312 traced

A young cluster of hot, massive stars in Scorpius, the heart of the Sco OB1 association.Kuhn et al. 2017, arXiv:1706.00017NASA Hubble, Caldwell 76
It holds about 15 O-type star systems and one Wolf-Rayet star, all very massive; a few other Wolf-Rayet stars lie outside its centre.Kuhn et al., arXiv:1706.00017

NGC 7522 traced

An old, scattered open cluster in Andromeda, more than twice the width of the full Moon on the sky.Steinicke, historical NGC/IC data; worked out from its numbersSandquist et al., arXiv:2210.11649
It is a moderately old open cluster, about 1.3 to 1.6 billion years old.Sandquist et al., arXiv:2210.11649

The Alpha Persei Cluster2 traced

A large, nearby group of bright young stars around Mirfak, the brightest star in Perseus.Kaler, STARS: Mirfak
It is easily visible to the naked eye and a fine sight in a small telescope.J. Kaler, Mirfak, University of Illinois

IC 46652 traced

A sparse, young open cluster in Ophiuchus, near the star Cebalrai.de Wit et al. 2005, arXiv:astro-ph/0511175Kaler, STARS: CebalraiSteinicke, historical NGC/IC data
It is visible to the naked eye in a dark sky.British Astronomical Association, IC4665 well placed for observation

The Muscleman Cluster2 traced

An open cluster in Cassiopeia.Alonso-Santiago et al. 2021, arXiv:2109.13959
It lies near the Double Cluster on the sky but at a fraction of its distance.Alonso-Santiago et al. 2021, A&A 656, A149

NGC 25472 traced

A young open cluster in Vela, a few tens of millions of years old.Manzi et al. 2007, arXiv:0712.0226Steinicke, historical NGC/IC data
Its young stars are used to study how dust discs disappear as planets form.Gorlova et al. 2007, ApJ 670, 516

The Omicron Velorum Cluster2 traced

One of the nearest young open clusters, a naked-eye group of bright stars in Vela.Marsden et al. 2009, Chromospheric emission in IC 2391 and IC 2602, arXiv:0907.0286Steinicke, historical NGC/IC data
Al Sufi recorded it in the 10th century.Steinicke, historical NGC/IC data

Westerlund 22 traced

A compact young cluster of very massive stars inside the glowing nebula Gum 29, in Carina.ESA/Hubble heic1509
Hubble's 25th-anniversary image in 2015 showed it.ESA/Hubble release heic1509

Trumpler 142 traced

The youngest and one of the most populous clusters in the Carina Nebula.ESA/Hubble heic1601
It holds HD 93129A, a pair of stars among the most massive and luminous in the Milky Way.The high-energy emission from HD 93129A near periastron (NASA NTRS)ESA/Hubble release heic1601

NGC 36032 traced

One of the most massive young star clusters in the Milky Way, in a giant glowing nebula in Carina.NASA, Star-Forming Nebula NGC 3603ESA/Hubble heic0715Steinicke, historical NGC/IC data
Its central cluster packs thousands of stars, many of them very massive, with half its light inside a radius of about 15 light-years.APOD, 5 October 2007; worked out from its numbersMelena et al. 2007, arXiv:0712.2621

Westerlund 13 traced

One of the most massive young star clusters known in the Milky Way, packed with supergiant and hypergiant stars, hidden behind heavy dust in Ara.Clark et al. 2005, arXiv:astro-ph/0504342ESO eso1034NASA APOD 2017 Jun 20
It holds some of the largest stars known, including red supergiants and stars classed as yellow hypergiants.APOD, 20 June 2017ESA/Hubble picture of the week potw1710
It holds a magnetar, CXOU J164710.2-455216.Muno et al. 2006, ApJ 636, L41

The Arches Cluster3 traced

The densest known cluster of young stars in the Milky Way, near the Galactic Centre.NASA, Hubble Peers into the Most Crowded Place in the Milky Way
It is only about 2 to 4 million years old; estimates differ.Hosek et al., arXiv:1808.02577
Dust hides it from visible light; it is seen in infrared and X-rays.NASA, Hubble Peers into the Most Crowded Place in the Milky Way

The Quintuplet Cluster3 traced

A young, massive star cluster near the Galactic Centre, named after five bright infrared sources in it.Figer, McLean & Morris 1999, arXiv:astro-ph/9903281Hußmann et al. 2011, Quintuplet present-day mass function, arXiv:1108.4331
It holds the Pistol Star, one of the most luminous stars known.NASA, Hubble Identifies What May Be the Most Luminous Star KnownMoneti et al. 1998, Spectroscopy of the Pistol and Quintuplet Stars
Dust hides it from visible light, so it has no parallax of its own; it is placed at the Galactic Centre's distance.Libralato et al., arXiv:2008.01741Hussmann et al. 2011, arXiv:1108.4331Stolte et al. 2014, ApJ 789, 115

The Jellyfish Nebula3 traced

The remnant of a supernova in Gemini, crashing into the molecular clouds around it.Chandra X-ray Center, IC 443 (2015)H.E.S.S. analysis of IC 443 (2025)
Gamma rays from it show that supernova remnants accelerate cosmic-ray protons.Ackermann et al. 2013, Science 339, 807
Its distance comes from the clouds it is hitting: where stars behind them start to look dimmed and reddened, using Gaia parallaxes with sky-survey colours.Zucker et al. 2020, A&A 633, A51

The Spaghetti Nebula3 traced

A huge, faint shell of tangled filaments left by a supernova tens of thousands of years ago, spanning Taurus and Auriga.NASA APOD, 7 Jan 2026Kinematics of SNR G180.0-01.7 (2026)
The neutron star its explosion left, PSR J0538+2817, is still racing away from the centre.Khabibullin et al. 2023, arXiv:2309.13670Ng et al. 2007, ApJ 654, 487
It spans about 3 degrees of sky, six times the width of the full Moon.APOD, 25 April 2016

Puppis A3 traced

A bright supernova remnant in Puppis, seen on the sky behind the larger Vela remnant.Dubner et al. 2013, A&A
The neutron star it left behind is moving fast enough to be nicknamed a 'cosmic cannonball'.Chandra, RX J0822-4300 in Puppis A (2007)
Its distance is uncertain; the published estimate has a wide margin of error.Ranasinghe & Leahy 2022, ApJ, Table 1

RCW 863 traced

The remnant of a supernova in Circinus, probably the one Chinese astronomers recorded in the year 185.Chandra X-ray Center, RCW 86 (2011)Broersen et al. 2014, MNRAS
If so, it is the oldest recorded supernova.Chandra, RCW 86 (2011)
One published estimate puts it 2.2 ± 0.4 kiloparsecs away.Ranasinghe & Leahy 2022, ApJ, Table 1

G1.9+0.33 traced

The youngest known supernova remnant in the Milky Way, near the Galactic Centre.Chandra X-ray Center, G1.9+0.3 (2008)13 years of Chandra monitoring of G1.9+0.3 (2024)
Its star exploded around 1900, but dust hid the explosion from everyone at the time.Carlton et al. 2011, arXiv:1106.4498Chandra, G1.9+0.3 (2008)
One published catalogue places it at the Galactic Centre's distance, 8.34 ± 0.16 kiloparsecs.Ranasinghe & Leahy 2022, ApJ, Table 1

The Manatee Nebula3 traced

A huge supernova remnant in Aquila, stretched out by the jets of the strange star SS 433 inside it.Safi-Harb et al. 2022, Manatee nebulaW 50 and SS 433 (2018)Kubota et al. 2010, SS 433 (V1343 Aquilae)
Its shape comes from SS 433's jets punching into the shell.Bowler & Keppens 2018, A&A 617, A29Safi-Harb et al. 2022, arXiv:2207.00573
One published estimate puts it 5.1 ± 0.4 kiloparsecs away.Ranasinghe & Leahy 2022, ApJ, Table 1Green, Catalogue of Galactic SNRs (2024): G39.7−2.0 is W50

Pa 303 traced

A faint nebula in Cassiopeia that is very probably the remnant of the supernova seen from China and Japan in 1181.Ritter et al. 2021, ApJLSchaefer 2023, MNRAS
Its central star is a rare, extremely hot remnant, thought to be left by a white-dwarf explosion or merger that did not destroy it.Gvaramadze et al. 2019, Nature 569, 684Ritter et al. 2021, arXiv:2105.12384
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 catalogue, ESA Gaia Archive; worked out from its numbers

RX J1713.7-39463 traced

A young supernova remnant in Scorpius that glows brightly in very-high-energy gamma rays.H.E.S.S. Collaboration 2018, A&ACassam-Chenai et al. 2004, A&AFukui et al. review: young SNRs (2021)
It may be the remnant of a supernova recorded in China in 393.Tsuji et al., arXiv:1609.07886
Its distance is uncertain; the published estimate has a wide margin of error.Ranasinghe & Leahy 2022, ApJ, Table 1

Vela Junior3 traced

A young supernova remnant seen on the sky behind the larger, older Vela remnant.Allen et al. 2015, ApJBerezhko 2014 reviewReview of SNRs in the IXPE era (2026)
It was found in X-ray images from the ROSAT satellite in 1998.Maxted et al., arXiv:1809.02249Slane et al. 2001, arXiv:astro-ph/0104353
It is seen through the much larger Vela supernova remnant, which lies closer to us.Slane et al. 2001, arXiv:astro-ph/0104353Maxted et al., arXiv:1809.02249

GRS 1915+1052 traced

A black hole about 12 times the Sun's mass feeding on a companion star, firing jets that seem to move faster than light.Reid et al. 2014, ApJL
In 1994 it became the first object in the Milky Way seen to throw out jets with apparent faster-than-light motion — an illusion of geometry.Mirabel & Rodriguez 1999, ARA&A 37, 409

MAXI J1820+0703 traced

A black hole in an X-ray binary that flared up in 2018, becoming one of the brightest X-ray sources in the sky.NASA, NICER maps light echoes (2019)
Its distance comes from a radio parallax of its compact radio jets.Atri et al. 2020, MNRAS 493, 81
Its distance comes from a radio parallax, measured by radio telescopes thousands of kilometres apart working as one.Atri et al. 2020, MNRAS 493, 81NRAO, Very Long Baseline Array

V4641 Sagittarii3 traced

A black hole of about 6 times the Sun's mass in orbit with a hot blue star.Morningstar et al. 2014 (citing MacDonald et al. 2014)V4641 Sgr binary evolution (2026)
In 1999 it flared up dramatically within a matter of hours, then faded again.Chaty et al. 2001, Astrophys. Space Sci. 276, 153Revnivtsev et al. 2002, A&A 391, 1013
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 catalogue, ESA Gaia Archive; worked out from its numbers

XTE J1118+4803 traced

A black hole about 7 times the Sun's mass high above the Milky Way's disc, feeding on a small orange star.Khargharia et al. 2013, ApJWagner et al. 2001, ApJ
It lies far above the Galactic plane, so very little dust dims it.McClintock et al. 2001, ApJ 551, L147Wagner et al. 2001, ApJ 556, 42
NASA's RXTE satellite found it during an outburst in 2000.McClintock et al. 2001, ApJ 551, L147

GRO J1655-403 traced

A black hole that throws out jets and feeds on a companion star in Scorpius.Chandra X-ray Center, GRO J1655-40 (2006)Zhang et al. 1997, ApJ
Its companion star contains elements forged in the supernova that made the black hole.Gonzalez Hernandez et al. 2007, arXiv:0705.2693
The Compton Gamma Ray Observatory found it in 1994.Gonzalez Hernandez et al. 2007, arXiv:0705.2693

M33 X-72 traced

A black hole of about 11 to 16 times the Sun's mass in an eclipsing pair with a giant star, in the Triangulum Galaxy.Orosz et al. 2007, NatureRamachandran et al. 2022, A&A
When its mass was measured in 2007, it was the only known black hole in an eclipsing binary.Orosz et al. 2007, arXiv:0710.3165

The Hulse–Taylor Pulsar4 traced

A pulsar in a tight orbit with another neutron star, whose slowly shrinking orbit gave the first evidence of gravitational waves.Weisberg, Nice & Taylor 2010, ApJNobel Prize in Physics 1993, press release
Its discoverers, Russell Hulse and Joseph Taylor, won the 1993 Nobel Prize in Physics.Nobel Prize in Physics 1993, press release
The two neutron stars orbit each other every 7.75 hours.Weisberg & Huang, arXiv:1606.02744; worked out from its numbersNobel Prize in Physics 1993, press release
About 17,000 light-years is an estimate from how much gas its signal passed through. A weak radio parallax gives about 13,400 light-years instead, and the two are still uncertain.Deller et al., arXiv:1806.10265; worked out from its numbers

The Double Pulsar3 traced

The only known pair of neutron stars in which both have been seen as pulsars, orbiting each other every 2.4 hours.Egron et al. 2017, ApJKramer et al. 2021, PRX
It gives the most precise test yet of general relativity's description of gravitational waves, as of 2021.Kramer et al. 2021, Phys. Rev. X 11, 041050
It was discovered in 2003 with the Parkes radio telescope in Australia.Burgay et al. 2003, Nature 426, 531Kramer et al. 2021, Phys. Rev. X 11, 041050

PSR B1257+123 traced

A millisecond pulsar orbited by the first planets ever confirmed outside the Solar System.Nitu et al. 2022, MNRASKonacki & Wolszczan 2003, ApJL
Aleksander Wolszczan and Dale Frail announced its planets in 1992.Penn State, Planets from the Very StartKonacki & Wolszczan 2003, ApJ 591, L147
Its distance comes from a radio parallax, measured by radio telescopes thousands of kilometres apart working as one.Yan et al. 2012, Proc. IAU Symp. 291NRAO, Very Long Baseline Array

PSR J1748-2446ad3 traced

The fastest-spinning pulsar known, turning 716 times a second, inside the globular cluster Terzan 5.Hessels et al. 2005, Science
Its equator moves at up to about a quarter of the speed of light.Hessels et al. 2006, arXiv:astro-ph/0601337; worked out from its numbers
It was discovered in 2004 with the Green Bank Telescope.Hessels et al. 2006, arXiv:astro-ph/0601337

Scorpius X-13 traced

A neutron star pulling gas from a companion star; after the Sun, it is the brightest steady X-ray source in the sky.NASA HEASARC, NICER Science Nugget, 7 Dec 2023
It was the first X-ray source found outside the Solar System, in 1962.NASA HEASARC, Early Observation of Sco X-1
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3 catalogue, ESA Gaia Archive

Hercules X-13 traced

An X-ray pulsar spinning every 1.24 seconds in a 1.7-day orbit with a companion star.Insight-HXMT study of Her X-1 (2026)
It was one of the first X-ray pulsars found, by the Uhuru satellite in 1971.Staubert et al. 2026, History of Turn-Ons of Hercules X-1Shakura, Kolesnikov & Postnov 2021, On the nature of the 35-day cycle in HZ Her/Her X-1
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 1338822021487330304; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Centaurus X-33 traced

The first X-ray pulsar discovered: a neutron star spinning every 4.8 seconds while it feeds on a massive companion.Flux variations and torque reversals of Cen X-3 (2025)
The Uhuru satellite found its pulses in 1971.Giacconi et al. 1971, ApJ
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 5337498593446516480; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Vela X-13 traced

An X-ray pulsar fed by the wind of a blue supergiant star it orbits every 9 days.Kretschmar et al. 1999Choquet et al. 2014, A&A
Its neutron star is unusually heavy, at about 1.8 times the Sun's mass or more.Kretschmar et al. 2021, Revisiting the archetypical wind accretor Vela X-1Rawls et al. 2011, Refined Neutron-Star Mass Determinations
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 5620657678322625920; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

SGR 1935+21543 traced

A magnetar — a neutron star with an enormous magnetic field — that in 2020 gave off the first fast radio burst seen from inside the Milky Way.Bochenek et al. 2020, NatureCHIME/FRB 2020, NatureZhang 2023, Rev. Mod. Phys.
Its 2020 radio burst linked fast radio bursts to magnetars.Bochenek et al. 2020, A fast radio burst associated with a Galactic magnetar
NASA's Swift satellite discovered it in 2014.Israel et al. 2016, The discovery, monitoring and environment of SGR J1935+2154

Procyon B3 traced

The white dwarf that orbits Procyon, one of the brightest stars in the sky.Bond et al. 2015, ApJKaler, STARS: Procyon
It orbits Procyon every 40.8 years.Bond et al. 2015, ApJ
J. M. Schaeberle first saw it in 1896.Bond et al. 2015, ApJ

LAWD 373 traced

A nearby white dwarf whose mass was measured by watching it bend the light of a background star.NASA, Hubble measures mass of a lone white dwarf (2023)
It is one of the nearest white dwarfs to the Sun.McGill et al. 2023, First semi-empirical test of the white dwarf mass-radius relationshipMcGill et al. 2018, A Predicted Astrometric Microlensing Event by a Nearby White Dwarf
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 5332606522595645952; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Stein 2051 B2 traced

A white dwarf whose mass was weighed in 2017 by how much it deflected the light of a star behind it, the effect predicted by Einstein's relativity.Sahu et al. 2017, Science
It orbits the red dwarf Stein 2051 A.Sahu et al. 2017, Relativistic deflection of background starlightNASA, Hubble Astronomers Develop a New Use for a Century-Old Relativity Experiment

ZTF J1901+14582 traced

A white dwarf only a little larger than the Moon, yet heavier than the Sun, spinning once every seven minutes.Caltech/IPAC press release (2021)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 4506869128279648512; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

G 29-383 traced

A pulsating white dwarf surrounded by a warm disc of dust, probably the crushed remains of rocky bodies.Jura 2003, ApJLReach et al. 2005, ApJL
Rocky material falling onto it shows that planets' debris can survive their star's death.Xu et al. 2014, Elemental Compositions of Two Extrasolar Rocky Planetesimals
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 2660358032257156736; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

UY Scuti3 traced

A red supergiant; a 2013 measurement put its radius at about 1,700 times the Sun's.Arroyo-Torres et al. 2013, A&A
A 2013 study put its radius at about 1,700 times the Sun's, though its uncertain distance makes that uncertain.Arroyo-Torres et al. 2013, A&A 554, A76; worked out from its numbers
It is a pulsating variable that changes in brightness over about two years.Arroyo-Torres et al. 2013, A&A 554, A76; worked out from its numbers

Hind's Crimson Star3 traced

A carbon star so red that John Russell Hind compared it to a drop of blood when he found it in 1845.AAVSO, LPV of the Month, March 2017
It pulses in brightness over about 14 months.NASA APOD, 2018 October 31, R Leporis: A Vampire's Star; worked out from its numbersKaler, Hind's Crimson Star
Carbon molecules in its atmosphere absorb its blue light.NASA APOD, 2018 October 31, R Leporis: A Vampire's StarKaler, Hind's Crimson Star

Delta Cephei3 traced

The prototype of the Cepheid variables, stars whose pulse rate tells how bright they really are — the rungs of the cosmic distance ladder.AAVSO, Variable Star of the Season: delta CepKaler, STARS: Delta Cephei
It brightens and fades every 5.37 days.Engle & Guinan 2017, The Secret Lives of Cepheids: δ CepThe Variable Sky Through the OGLE Eye (2025)
John Goodricke discovered its variation in 1784.The Variable Sky Through the OGLE Eye (2025)

RR Lyrae3 traced

The prototype of the RR Lyrae stars, old pulsating stars used to measure distances across the Milky Way.Kaler, STARS: RR LyraeAAVSO, Variable Star of the Season: RR Lyrae
It brightens and fades every 0.567 days, about 13.6 hours.Le Borgne et al. 2014, The historical vanishing of the Blazhko effect of RR LyrKaler, RR Lyrae
Williamina Fleming discovered its variability in 1901.Poretti et al. 2016, The magnificent past of RR Lyrae variables

P Cygni3 traced

A luminous blue variable star that suddenly appeared in 1600, faded from naked-eye view in 1626, and has stayed around fifth magnitude since the 1700s.Israelian & de Groot 1999, Space Sci. Rev.Kaler, STARS: P Cygni
It gives its name to the 'P Cygni profile', the spectral sign of a star blowing off gas.Israelian & de Groot 1999, P Cygni: An Extraordinary Luminous Blue Variable
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 2061242908036996352; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Epsilon Aurigae3 traced

A bright star eclipsed every 27 years by a huge, dark disc of dust that takes nearly two years to pass.NASA, Mystery of the Fading Star (2010)Kaler, STARS: Almaaz
Its last eclipse ran from 2009 to 2011.High cadence measurement of sodium and potassium absorption during the 2009-2011 eclipse of epsilon AurigaeStencel 2010, Epsilon Aurigae in Total Eclipse, 2010
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 205499655242974464; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

The Pistol Star3 traced

One of the most luminous stars known, a luminous blue variable near the Galactic Centre, hidden from visible light by dust.Geballe et al. 2000, ApJNASA, A Brilliant Star in Milky Way's Core
It lies in the Quintuplet Cluster, inside the Pistol Nebula: gas it threw off, lit mainly by the cluster's other hot stars.Figer et al. 1999, High Resolution Infrared Imaging and Spectroscopy of the Pistol NebulaLang et al. 1999, Radio Detections of Stellar Winds from the Pistol Star
Dust dims it by 20 to 30 magnitudes in visible light; it is placed at the Galactic Centre's distance.Martayan et al. 2011, High-angular resolution observations of the Pistol StarGaia DR3, cone search 5 arcsec around the SIMBAD position (no source)SIMBAD, [FMM95] 3 (no parallax listed)

R136a13 traced

The most massive star known, in the star cluster R136 at the heart of the Tarantula Nebula in the Large Magellanic Cloud.Kalari et al. 2022, ApJ
Recent estimates put its mass between about 150 and 215 times the Sun's.Kalari et al. 2022, Resolving the core of R136 in the opticalBrands et al. 2022, The R136 star cluster dissected with HST/STIS III
It is placed at the Large Magellanic Cloud's distance, measured from eclipsing binary stars.Pietrzyński et al. 2019, A distance to the Large Magellanic Cloud precise to one per centKalari et al. 2022, Resolving the core of R136 in the optical

WOH G643 traced

A huge star in the Large Magellanic Cloud wrapped in a cocoon of dust, long classed as a red supergiant. What it is now is argued over.ESO, eso2417 (2024)Munoz-Sanchez et al. 2024
Announced in 2024, the VLT Interferometer's first close-up image of a star in another galaxy shows this one, observed in December 2020.ESO press release eso2417, 2024Ohnaka et al. 2024, A&A (ESO copy)
It is placed at the Large Magellanic Cloud's distance, measured from eclipsing binary stars.Pietrzyński et al. 2019, A distance to the Large Magellanic Cloud precise to one per centOhnaka et al. 2024, A&A (ESO copy)

Przybylski's Star3 traced

One of the strangest stars known: its spectrum is crowded with rare heavy elements, and iron is about ten times scarcer than in the Sun.Shulyak et al. 2010, A&AHubrig et al. 2018, MNRAS
Antoni Przybylski described it in 1961.Cowley et al. 2000, MNRASAndrievsky et al. 2023, An enigma of Przybylski's star
Claims of short-lived radioactive elements in its spectrum are still argued over.Andrievsky et al. 2023, An enigma of Przybylski's starAndrievsky et al. 2023, Abundance of radioactive technetium in Przybylski's star revisitedCowley et al. 2000, MNRAS

Methuselah Star3 traced

One of the oldest stars known nearby, a metal-poor subgiant passing through the Sun's neighbourhood from the Milky Way's halo.NASA, Hubble Finds Birth Certificate of Oldest Known Star (2013)Bond et al. 2013, ApJL
Some age estimates have come close to the age of the Universe itself.Bond et al. 2013, HD 140283: A Star in the Solar Neighborhood
It holds only a few thousandths of the Sun's share of iron.Bond et al. 2013, HD 140283: A Star in the Solar Neighborhood; worked out from its numbers

Naos3 traced

One of the brightest O-type stars in the sky, a very hot, luminous supergiant racing through space.Kaler, STARS: Naos
It is an O-type star, with a surface around 40,000 degrees.Howarth & van Leeuwen 2019, The distance, rotation, and physical parameters of zeta PupBouret et al. 2012, Properties of Galactic early-type O-supergiants
It is a runaway star, moving fast from where it was born.Howarth & van Leeuwen 2019, The distance, rotation, and physical parameters of zeta PupSchilbach & Röser 2008, On the origin of field O-type stars

Regor3 traced

The brightest Wolf–Rayet star in the sky, in a close pair with a massive O-type star.Kaler, STARS: Regor
Wolf–Rayet stars are massive stars casting off their outer layers, which leaves most of them short of hydrogen.Crowther 2007, Physical Properties of Wolf-Rayet StarsNASA, Webb Telescope Captures Rarely Seen Prelude to Supernova, 14 March 2023
Its distance comes from a parallax measured by the Hipparcos satellite: the tiny yearly shift in its position as the Earth circles the Sun.van Leeuwen 2007, A&A 474, 653; HIP 39953, read in the ESA Gaia archive table public.hipparcos_newreduction; worked out from its numbersvan Leeuwen 2007, the same paper free to read (arXiv)SIMBAD, gam02 Vel

Plaskett's Star3 traced

One of the most massive binary stars known, two hot O-type stars orbiting every 14.4 days.Re-examining photographic spectra of Plaskett's Star (2024)Linder et al. 2008, A&A
Plaskett found it to be a binary in 1922.Linder et al. 2008, High resolution optical spectroscopy of Plaskett's star
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 3131898712120792064; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

AG Carinae3 traced

A luminous blue variable star surrounded by a shell of gas it threw off thousands of years ago.ESA/Hubble, heic2105 (2021)
It is one of the brightest stars in the Milky Way, shining like about a million Suns.ESA/Hubble heic2105, Hubble Celebrates 31st BirthdayNASA, AG Carinae: A Luminous Blue Variable StarGroh et al. 2006, AG Carinae: a Luminous Blue Variable with a high rotational velocity
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 5338220285385672064; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

V838 Monocerotis3 traced

A star that brightened suddenly in 2002, lighting up the dust around it in a spectacular 'light echo' Hubble filmed for years.ESA/Hubble, heic0617 (2006)
The outburst may have been two stars merging.Ortiz-León et al. 2020, SiO maser astrometry of the red transient V838 MonocerotisKamiński et al. 2021, V838 Monocerotis as seen by ALMA
Its distance comes from a radio parallax, measured by radio telescopes thousands of kilometres apart working as one.Ortiz-León et al. 2020, SiO maser astrometry of the red transient V838 Monocerotis; worked out from its numbersNRAO, Very Long Baseline ArrayReid et al. 2019, ApJ

S5-HVS14 traced

A star flung out of the Milky Way at about 1,700 km/s by the black hole at its centre, Sagittarius A*.Koposov et al. 2020, MNRAS
It is crossing the Galaxy at about 1,755 km/s, fast enough to leave the Milky Way for ever.Koposov et al. 2020, The Great Escape
The likeliest story: it was one of a pair, and the black hole kept its partner (the Hills mechanism — the paper weighs others).Koposov et al. 2020, The Great Escape
It is a white A-type star of about 2.35 Suns.Koposov et al. 2020, The Great Escape

WR 1243 traced

A runaway Wolf–Rayet star wrapped in the nebula M1-67, the clumpy gas it has shed.Marchenko, Moffat & Crowther 2010, ApJLNASA, Nebula M1-67 around Star WR124
The James Webb Space Telescope imaged it and its dusty nebula in June 2022; NASA released the picture in 2023.NASA, Webb Telescope Captures Rarely Seen Prelude to Supernova, 14 March 2023
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 4513494205567536512; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

SS 4333 traced

A star whose compact companion — probably a black hole — fires two jets at about a quarter of the speed of light.Kubota et al. 2010, ApJ
Its jets wobble round in a cone every 162 days.Bowler 2020, W50 morphology and the dynamics of SS 433 formationBlundell & Bowler 2005, Symmetry in the changing jets of SS 433
It sits inside the Manatee Nebula (W50), which its jets are stretching.NRAO, W50: The Manatee NebulaNRAO, Microquasar Makes a Giant Manatee NebulaBowler 2020, W50 morphology and the dynamics of SS 433 formation

Kepler-163 traced

A pair of stars orbited by a Saturn-sized planet that sees two suns — a real Tatooine.Doyle et al. 2011, ScienceNASA Exoplanet Catalog: Kepler-16 b
Kepler-16 b, announced in 2011, was the first planet confirmed by transits to orbit two stars.NASA/JPL, NASA's Kepler Discovery Confirms First Planet Orbiting Two Stars, 15 Sept 2011Doyle et al. 2011, Kepler-16: A Transiting Circumbinary PlanetWelsh et al. 2013, Recent Kepler Results On Circumbinary Planets
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 2133476355197071616; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Kepler-222 traced

A Sun-like star whose planet Kepler-22 b was the first Kepler found in its star's habitable zone.NASA JPL news release, 5 Dec 2011Borucki et al. 2012, ApJ
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 2127941757262806656; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Kepler-903 traced

A Sun-like star with eight known planets, as many as the Solar System.NASA release 17-098 (2017)Shallue & Vanderburg 2018, AJ
Its eighth planet was found in 2017 with the help of machine learning.Shallue & Vanderburg 2018, AJ
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.Gaia DR3, source_id 2132193431285570304; worked out from its numbersESA, How does Gaia study the Milky Way? (explains parallax)

Gliese 5813 traced

A nearby red dwarf with several planets, at the centre of years of debate over which of them are real.Robertson et al. 2014, Science
Some of its claimed planets were later shown to be signals from the star's own activity.Robertson et al. 2014, Science 345, 440Robertson et al. 2014, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, GJ 581Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

Gliese 667 C3 traced

A red dwarf in a triple-star system with planets, at least one in its habitable zone.ESO, eso1328 (2013)Anglada-Escude et al. 2013, A&A
From its planets, the two other suns of this triple system would look like a pair of very bright stars.ESO press release eso1328, 2013
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, GJ 667 CPerryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

HD 1897333 traced

An orange star with a hot Jupiter, HD 189733 b — one of the most studied planets outside the Solar System.Cubillos et al. 2023, A&ANASA Exoplanet Archive, HD 189733 spectral type
Hubble measurements reported in 2013 showed the planet's colour: a deep blue.Evans et al. 2013, ApJL 772, L16Evans et al. 2013, the same paper free to read (arXiv)NASA news release 13-202, 11 July 2013
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, HD 189733Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

PDS 702 traced

A young star with two giant planets caught in the act of forming, inside a gap in its disc.Haffert et al. 2019, Nature Astronomy
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, PDS 70Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

AU Microscopii3 traced

A young red dwarf with an edge-on disc of dust and transiting planets.Plavchan et al. 2020, Nature
It is only a few tens of millions of years old.Plavchan et al. 2020, Nature 582, 497Plavchan et al. 2020, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, GJ 803Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

51 Eridani3 traced

A young star with a directly imaged young Jupiter-like planet, 51 Eridani b.Macintosh et al. 2015, Science
Its planet was announced in 2015: the Gemini Planet Imager photographed it directly.Macintosh et al. 2015, Science 350, 64Macintosh et al. 2015, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, 51 EriPerryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

KELT-93 traced

A star on the line between spectral types A and B, about 10,170 K, with the hottest giant planet known, KELT-9 b.Gaudi et al. 2017, NatureOhio State Astronomy news (2017)
The dayside of KELT-9 b is hotter than many stars, about 4,600 K.Gaudi et al. 2017, Nature 546, 514Gaudi et al. 2017, the same paper free to read (arXiv)Lehigh University news, A Planet Hotter Than Most Stars
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, HD 195689Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

Kepler-4443 traced

An ancient star with five small planets, each between Mercury and Venus in size, formed when the Universe was under 20% of its present age.Campante et al. 2015, ApJ
The star is about 11 billion years old, more than twice the Sun's age.Campante et al. 2015, ApJ 799, 170; worked out from its numbersCampante et al. 2015, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, KOI-3158Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

Gliese 12143 traced

A small red dwarf with a planet between Earth and Neptune in size, wrapped in a thick layer of haze or cloud.Kempton et al. 2023, NatureKreidberg et al. 2014, Nature
Its planet GJ 1214 b is a classic 'sub-Neptune', a kind of world the Solar System does not have.Kempton et al. 2023, Nature 620, 67Kempton et al. 2023, the same paper free to read (arXiv)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, GJ 1214Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

WD 1856+5342 traced

A white dwarf with a giant planet that survived its star's death, crossing in front of it every 1.4 days.Vanderburg et al. 2020, NatureNASA Exoplanet Archive, WD 1856+534 b
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD, WD 1856+534Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)

Luyten 726-84 traced

A pair of tiny red dwarfs, BL Ceti and UV Ceti, one of the nearest star systems to the Sun.RECONS, The 100 Nearest Star Systems (Georgia State)
UV Ceti is the prototype of the flare stars, which brighten violently within minutes.AAVSO Variable Star of the Season, UV Ceti and the flare stars (archived copy)
Willem Luyten discovered the pair in 1948–49.Potemine 2010, arXiv:1004.1557
Spectral type M5.5V + M6V (SIMBAD).SIMBAD, GJ 65

Ross 1544 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.RECONS, The 100 Nearest Star Systems (Georgia State); worked out from its numbers
It is a flare star.Wargelin et al. 2008, ApJ 676, 610Wargelin et al. 2008, the same paper free to read (arXiv)HyperPhysics, Ross 128, Ross 154 and Ross 248
Spectral type M3.5Ve (SIMBAD).SIMBAD, GJ 729
At magnitude 10.43 (V) it is too faint to see with the naked eye.SIMBAD, GJ 729NASA Imagine the Universe, Ask an Astrophysicist

Ross 2483 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.RECONS, The 100 Nearest Star Systems (Georgia State); worked out from its numbers
It is moving towards us; in about 36,000 years it will pass within about 3 light-years.Bailer-Jones 2022, ApJL 935, L9; worked out from its numbersBailer-Jones 2022, the same paper free to read (arXiv)
Spectral type M5.0V (SIMBAD).SIMBAD, GJ 905

Lacaille 93523 traced

Two super-Earths were found orbiting it in 2020; two more were reported in 2026.Jeffers et al. 2020, Science (arXiv:2006.16372)Hartogh et al. 2026, A&A 707, A93
Spectral type M2V (SIMBAD).SIMBAD, GJ 887
At magnitude 7.39 (V) it is too faint to see with the naked eye.SIMBAD, GJ 887NASA Imagine the Universe, Ask an Astrophysicist

Ross 1284 traced

A quiet red dwarf with a temperate planet of at least 1.35 Earth masses.Bonfils et al. 2018, A&A
Its planet Ross 128 b, found in 2017, orbits every 9.9 days.Bonfils et al. 2018, A&A 613, A25Bonfils et al. 2018, the same paper free to read (arXiv)ESO press release eso1736, 15 November 2017
Spectral type dM4 (SIMBAD).SIMBAD, GJ 447
At magnitude 11.15 (V) it is too faint to see with the naked eye.SIMBAD, GJ 447NASA Imagine the Universe, Ask an Astrophysicist

EZ Aquarii3 traced

A triple system of three red dwarfs, one of the nearest star systems to the Sun.Delfosse et al. 1999, A&ARECONS, The One Hundred Nearest Star Systems (list as of 2012)SIMBAD, EZ Aqr
Two of its stars orbit each other in under 4 days.Delfosse et al. 1999, A&A (arXiv:astro-ph/9909409)
At magnitude 12.38 (V) it is too faint to see with the naked eye.SIMBAD, GJ 866NASA Imagine the Universe, Ask an Astrophysicist

61 Cygni3 traced

A pair of orange dwarf stars, the first star whose distance was ever measured.Kaler, STARS: 61 CygniSIMBAD, 61 Cyg A, K5VSIMBAD, 61 Cyg B, K7VKaler, STARS: Achird
Friedrich Bessel measured its parallax in 1838, the first time anyone gauged the distance to a star.Perryman 2012, Eur. Phys. J. H 37, The History of AstrometryPerryman 2012, the same paper free to read (arXiv)
It has one of the largest proper motions of any naked-eye star.ESA Gaia Image of the Week, 13 May 2025

Struve 23983 traced

A pair of red dwarfs in Draco.RECONS, The One Hundred Nearest Star Systems (list as of 2012); worked out from its numbersSIMBAD, GJ 725 A, M3VSIMBAD, GJ 725 B, M3.5VRoman 1987, PASP 99, 695 (IAU constellation boundaries)
Spectral type M3V + M3.5V (SIMBAD).SIMBAD, GJ 725 ASIMBAD, GJ 725 B
At magnitude 8.93 (V) it is too faint to see with the naked eye.SIMBAD, GJ 725 ANASA Imagine the Universe, Ask an Astrophysicist

Groombridge 343 traced

A pair of red dwarfs in Andromeda, with planets around the brighter one.Pinamonti et al. 2018, A&A 617, A104; worked out from its numbersSIMBAD, GJ 15 A, M2VSIMBAD, GJ 15 B, M3.5VRoman 1987, PASP 99, 695 (IAU constellation boundaries)
Spectral type M2V + M3.5V (SIMBAD).SIMBAD, GJ 15 ASIMBAD, GJ 15 B
At magnitude 8.14 (V) it is too faint to see with the naked eye.SIMBAD, GJ 15 ANASA Imagine the Universe, Ask an Astrophysicist

DX Cancri3 traced

A very faint, low-mass red dwarf near the Sun, about 0.09 solar masses.SIMBAD, DX Cnc, M6.5VeRECONS, The One Hundred Nearest Star Systems (list as of 2012)
It is a flare star.GCVS via VizieR, B/gcvsMedina et al. 2022, ApJ 928, 185Medina et al. 2022, the same paper free to read (arXiv)
Spectral type M6.5Ve (SIMBAD).SIMBAD, GJ 1111

Epsilon Indi4 traced

An orange dwarf star with a giant planet and a pair of brown dwarfs in orbit around it.Matthews et al. 2024, NatureMcCaughrean et al. 2004, A&AKaler, STARS: Epsilon IndiKaler, STARS: Achird
Its giant planet, Epsilon Indi Ab, was photographed directly by the James Webb Space Telescope; the images were taken in 2023 and reported in 2024.Matthews et al. 2024, NatureMatthews et al. 2024, the same paper free to read (arXiv)
Its brown dwarf pair, Epsilon Indi Ba and Bb, orbit far out from the star.Scholz et al. 2003, A&A 398, L29Scholz et al. 2003, the same paper free to read (arXiv)McCaughrean et al. 2004, A&A 413, 1029McCaughrean et al. 2004, the same paper free to read (arXiv)
Spectral type K5V (SIMBAD).SIMBAD, GJ 845

GJ 10613 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 1061 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M5.5V (SIMBAD).SIMBAD, GJ 1061
At magnitude 13.07 (V) it is too faint to see with the naked eye.SIMBAD, GJ 1061NASA Imagine the Universe, Ask an Astrophysicist

YZ Ceti4 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, YZ Cet spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has three known small planets in tight orbits.Astudillo-Defru et al. 2017, A&A (arXiv:1708.03336)
Spectral type M4.0Ve (SIMBAD).SIMBAD, GJ 54.1
At magnitude 12.07 (V) it is too faint to see with the naked eye.SIMBAD, GJ 54.1NASA Imagine the Universe, Ask an Astrophysicist

Luyten's Star4 traced

A red dwarf in Canis Minor with planets, one in its habitable zone.Astudillo-Defru et al. 2017, A&A 602, A88; worked out from its numbersRoman 1987, PASP 99, 695 (IAU constellation boundaries)SIMBAD, Luyten's Star, M3.5V
In 2017 a radio message, 'Sónar Calling GJ 273b', was beamed towards its planet.Lantin et al. 2021, arXiv:2110.13080Caballero 2022, arXiv:2205.11618
Spectral type M3.5V (SIMBAD).SIMBAD, GJ 273
At magnitude 9.87 (V) it is too faint to see with the naked eye.SIMBAD, GJ 273NASA Imagine the Universe, Ask an Astrophysicist

Teegarden's Star4 traced

A very small, faint red dwarf with several Earth-mass planets, found only in 2003.Zechmeister et al. 2019, A&A 627, A49Dreizler et al. 2024, A&A
It was discovered in archived sky survey data by a team led by Bonnard Teegarden.Teegarden et al. 2003, ApJL (NASA NTRS copy)NASA JPL news, Newly Discovered Star May Be Third-Closest
Spectral type dM6 (SIMBAD).SIMBAD, Teegarden's Star
At magnitude 15.14 (V) it is too faint to see with the naked eye.SIMBAD, Teegarden's StarNASA Imagine the Universe, Ask an Astrophysicist

Kapteyn's Star4 traced

A red dwarf from the Milky Way's halo, passing through the Sun's neighbourhood on a backwards orbit round the galaxy.Anglada-Escude et al. 2014, MNRASGuinan et al. 2016, ApJ
It has one of the largest proper motions of any star.ESA Gaia Image of the Week, 13 May 2025Linda Hall Library, Jacobus Kapteyn
Spectral type M1VIp (SIMBAD).SIMBAD, GJ 191
At magnitude 8.85 (V) it is too faint to see with the naked eye.SIMBAD, GJ 191NASA Imagine the Universe, Ask an Astrophysicist

Lacaille 87603 traced

The brightest red dwarf in the sky, yet just too faint for the unaided eye.NASA Science, Types of StarsSIMBAD, Lacaille 8760, V = 6.68
Spectral type M1V (SIMBAD).SIMBAD, GJ 825
At magnitude 6.68 (V) it is just past the usual naked-eye limit of about 6.5; binoculars show it.SIMBAD (CDS, Harvard mirror): AX Mic, 2000A&A...355L..27HNASA Imagine the Universe, Ask an AstrophysicistNASA Skywatching

SCR 1845-63574 traced

A very faint red dwarf with a cold brown dwarf companion.Biller et al. 2006, ApJ 641, L141SIMBAD, SCR 1845-6357, M8.5V, V = 17.40
Its T-type brown dwarf companion was found in 2006.Biller et al. 2006, ApJL, Discovery of a very nearby brown dwarf
Spectral type M8.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): SCR J1845-6357, 2006AJ....132.2360H
At magnitude 17.4 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): SCR J1845-6357, 2011AJ....141...21WNASA Imagine the Universe, Ask an Astrophysicist

Kruger 603 traced

A pair of red dwarfs in Cepheus that orbit each other every 44.6 years.Dal 2011, PASA 28, 365; worked out from its numbersSixth Catalog of Orbits of Visual Binary Stars (GSU copy)RECONS, The One Hundred Nearest Star Systems (list as of 2012)Roman 1987, PASP 99, 695 (IAU constellation boundaries)
The fainter star, DO Cephei, is a flare star.Dal 2012, White-light flares on Kruger 60B (DO Cep)
At magnitude 9.59 (V) it is too faint to see with the naked eye.Hipparcos Catalogue, HIP 110893, table public.hipparcos in the ESA Gaia archiveNASA Imagine the Universe, Ask an Astrophysicist

DENIS J1048-39564 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, DENIS J1048.0-3956 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is an ultracool dwarf at the low-mass end of the main sequence.Stelzer et al. 2012, A&A, The ultracool dwarf DENIS-P J104814.7-395606
Spectral type M8.5Ve (SIMBAD).SIMBAD (CDS, Harvard mirror): DENIS J104814.7-395606, 2004AJ....128.2460H
At magnitude 17.53 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): DENIS J104814.7-395606, 2005AJ....130..337CNASA Imagine the Universe, Ask an Astrophysicist

UGPS J0722-05403 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, UGPS J072227.51-054031.2 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
When it was found in 2010 it was the coldest brown dwarf known, at about 520 K, a few hundred degrees above absolute zero.Lucas et al. 2010, MNRAS, The discovery of a very cool, very nearby brown dwarf
Spectral type T9 (SIMBAD).SIMBAD (CDS, Harvard mirror): UGPS J072227.51-054031.2, 2010MNRAS.408L..56L

Ross 6143 traced

A pair of red dwarfs in Monoceros orbiting each other every 16.6 years.Sixth Catalog of Orbits of Visual Binary Stars (GSU copy); worked out from its numbersBenedict et al. 2016, AJRECONS, The One Hundred Nearest Star Systems (list as of 2012)Roman 1987, PASP 99, 695 (IAU constellation boundaries)
Its faint companion, Ross 614 B, was first seen in 1955.Coppenbarger, Henry & McCarthy 1994, AJ 107, 1551
At magnitude 11.1 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): Ross 614, 2012yCat.1322....0ZNASA Imagine the Universe, Ask an Astrophysicist

Wolf 10614 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, Wolf 1061 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has three known planets, found in 2015.Wright et al. 2016, ApJL, Three planets orbiting Wolf 1061 (arXiv December 2015)NASA Exoplanet Archive, Planetary Systems Composite: Wolf 1061
Spectral type M3V (SIMBAD).SIMBAD (CDS, Harvard mirror): Wolf 1061, 2002AJ....123.2002H
At magnitude 10.07 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): Wolf 1061, 2009AJ....137.4186LNASA Imagine the Universe, Ask an Astrophysicist

Wolf 4243 traced

A pair of very small red dwarfs orbiting each other.Benedict et al. 2016, AJRECONS, The One Hundred Nearest Star Systems (list as of 2012)SIMBAD, Wolf 424 = GJ 473
Spectral type M5.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): Wolf 424, 2002AJ....123.2002H
At magnitude 12.47 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): Wolf 424, 1992AJ....104..340LNASA Imagine the Universe, Ask an Astrophysicist

Gliese 14 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 1 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is the first entry in the Gliese Catalogue of Nearby Stars.I. N. Reid, STScI, Nearby star catalogues and PMSUSIMBAD (CDS, Harvard mirror): GJ 1
Spectral type M2V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 1, 1982MSS...C03....0H
At magnitude 8.56 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 1, 2010MNRAS.403.1949KNASA Imagine the Universe, Ask an Astrophysicist

TZ Arietis4 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, TZ Ari spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has at least one known planet.Quirrenbach et al. 2022, A&A, Two Saturn-mass planets orbiting active stars
Spectral type M4.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): TZ Ari, 1991ApJS...77..417K
At magnitude 12.3 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): TZ Ari, 1992AJ....104..340LNASA Imagine the Universe, Ask an Astrophysicist

Gliese 6873 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 687 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has a Neptune-mass planet, found in 2014.Burt et al. 2014, ApJ, Gliese 687 b: a Neptune-mass planetNASA Exoplanet Archive, Planetary Systems Composite: GJ 687
Spectral type M3.0V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 687, 2015A&A...577A.128A

Gliese 6744 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 674 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has a Neptune-mass planet in a 4.7-day orbit.Bonfils et al. 2007, A&A, HARPS search X: GJ 674
Spectral type M3V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 674, 2006A&A...460..695T
At magnitude 9.41 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 674, 2010MNRAS.403.1949KNASA Imagine the Universe, Ask an Astrophysicist

LHS 2923 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, LHS 292 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M6.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): LHS 292, 1993ApJ...406..701K
At magnitude 15.78 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): LHS 292, 2012yCat.1322....0ZNASA Imagine the Universe, Ask an Astrophysicist

WISE 1639-68473 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, WISE J163940.83-684738.6 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is a Y dwarf, one of the coldest classes of brown dwarf, at roughly 360–400 K, about the temperature of boiling water.Leggett et al. 2017, ApJ, The Y-type brown dwarfsSchneider et al. 2015, ApJ, HST spectroscopy of brown dwarfs discovered with WISEKirkpatrick et al. 2021, field substellar mass function (Table)
Spectral type Y0pec (SIMBAD).SIMBAD (CDS, Harvard mirror): WISE J163940.83-684738.6, 2015ApJ...804...92SKirkpatrick et al. 2021, field substellar mass function (Table)

WISE 1741+25533 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, WISEP J174124.25+255319.5 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type T9 (SIMBAD).SIMBAD (CDS, Harvard mirror): WISEP J174124.25+255319.5, 2011ApJS..197...19KKirkpatrick et al. 2021, field substellar mass function (Table)
Its distance comes from a measured parallax. In the Sloan survey it shows only in the reddest filter, z, and it was picked out in data from the WISE infrared survey.Kirkpatrick et al. 2021, field substellar mass function (Table)Scholz et al. 2011, A&A, Two very nearby ultracool brown dwarfs

GJ 12454 traced

A triple system of small red dwarfs in Cygnus.Benedict et al. 2016, AJ; worked out from its numbersRECONS, The One Hundred Nearest Star Systems (list as of 2012)Roman 1987, PASP 99, 695 (IAU constellation boundaries)
Its two brighter stars, A and B, are flare stars.Lurie et al. 2015, ApJ, Kepler Flares III: GJ 1245 A and B
Spectral type M5.5Ve (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 1245 A, 1989ApJS...71..245K
At magnitude 13.13 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 1245 A, 2012yCat.1322....0ZNASA Imagine the Universe, Ask an Astrophysicist

Gliese 8764 traced

A red dwarf with four planets, the first red dwarf found to have one.Rivera et al. 2010, ApJMarcy et al. 1998, ApJ 505, L147
Its first planet, Gliese 876 b, was found in 1998.Marcy et al. 1998, ApJL, A planetary companion to the nearby M4 dwarf Gliese 876NASA Exoplanet Archive, Planetary Systems Composite: GJ 876
Spectral type M3.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 876, 1983SAAOC...7..106W
At magnitude 10.19 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 876, 2009AJ....137.4186LNASA Imagine the Universe, Ask an Astrophysicist

LHS 2883 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, LHS 288 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M5.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): LHS 288, 1991AJ....101..662B
At magnitude 13.92 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): LHS 288, 2008MNRAS.389..585CNASA Imagine the Universe, Ask an Astrophysicist

GJ 10024 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 1002 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has two known Earth-mass planets in its habitable zone, found in 2022.Suárez Mascareño et al. 2023, A&A, Two temperate Earth-mass planets orbiting GJ 1002 (arXiv December 2022)NASA Exoplanet Archive, Planetary Systems Composite: GJ 1002
Spectral type M5.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 1002, 1983SAAOC...7..106W
At magnitude 13.84 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 1002, 2012yCat.1322....0ZNASA Imagine the Universe, Ask an Astrophysicist

DENIS J0255-47003 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, DENIS J025503.3-470049 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It lies close to the boundary between L and T brown dwarfs, where silicate and iron clouds are thought to break up or disappear.Latitudinal chemical and cloud variations in the atmosphere of a brown dwarf, arXiv preprint, July 2026
Spectral type L9 (SIMBAD).SIMBAD (CDS, Harvard mirror): 2MASS J02550357-4700509, 2014AJ....147...34S

Groombridge 16183 traced

An orange dwarf star in Ursa Major, cooler and smaller than the Sun.RECONS, The One Hundred Nearest Star Systems (list as of 2012); worked out from its numbersSIMBAD, Groombridge 1618, K6VeBoyajian et al. 2012, ApJKaler, STARS: AchirdRoman 1987, PASP 99, 695 (IAU constellation boundaries)Roman 1987, constellation boundaries (VizieR VI/42); worked out from its position
Spectral type K6VeFe-1 (SIMBAD).SIMBAD (CDS, Harvard mirror): Groombridge 1618, 1989ApJS...71..245K
At magnitude 6.61 (V) it is just past the usual naked-eye limit of about 6.5; binoculars show it.SIMBAD (CDS, Harvard mirror): Groombridge 1618, 2009ApJ...694.1085VNASA Imagine the Universe, Ask an AstrophysicistNASA Skywatching

Gliese 4122 traced

A pair of red dwarfs; the fainter one is the variable star WX Ursae Majoris.RECONS, The One Hundred Nearest Star Systems (list as of 2012)SIMBAD, WX UMa, M6.0V, type Er*
Spectral type M1.0V + M6.0V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 412 A, 2013AJ....145..102LSIMBAD (CDS, Harvard mirror): GJ 412 B, 2015A&A...577A.128A

AD Leonis4 traced

A highly active red dwarf flare star in Leo.Mohan et al. 2024, arXiv 2402.00185 (AD Leo radio bursts) (A&A 686, A51 (2024)); worked out from its numbersarXiv 2003.06163 (AD Leo spectra)SIMBAD, AD Leo, dM3Roman 1987, PASP 99, 695 (IAU constellation boundaries)
It flares often, brightening within minutes.Bai et al. 2023, Photometric observations of flares on AD Leo from GWAC-F30 and TESSMuheki et al. 2020, A&A, High-resolution spectroscopy of flares and CMEs on AD Leo
Spectral type dM3 (SIMBAD).SIMBAD (CDS, Harvard mirror): AD Leo, 2019AJ....157...63K
At magnitude 9.52 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): AD Leo, 2012yCat.1322....0ZNASA Imagine the Universe, Ask an Astrophysicist

Gliese 8323 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 832 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M1.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 832, 1995AJ....110.1838R
At magnitude 8.67 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 832, 2010MNRAS.403.1949KNASA Imagine the Universe, Ask an Astrophysicist

Gliese 6823 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 682 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M3.5V (SIMBAD).SIMBAD (CDS, Harvard mirror): GJ 682, 1995AJ....110.1838R
At magnitude 10.95 (V) it is too faint to see with the naked eye.SIMBAD (CDS, Harvard mirror): GJ 682, 2010MNRAS.403.1949KNASA Imagine the Universe, Ask an Astrophysicist

EV Lacertae3 traced

A young, very active red dwarf flare star in Lacerta.arXiv 2507.01754 (SPIRou magnetometry of AU Mic and EV Lac); worked out from its numbersarXiv 2509.17911 (EV Lac activity)Osten et al. 2010, ApJRoman 1987, PASP 99, 695 (IAU constellation boundaries)
In 2008 the Swift satellite caught it giving off a flare thousands of times stronger than the Sun's largest.NASA, Pipsqueak Star Unleashes Monster FlareOsten et al. 2010, ApJ 721, The Mouse that Roared
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.SIMBAD (CDS, Harvard mirror): EV Lac, Gaia EDR3, 2020yCat.1350....0GHyperPhysics, Stellar Parallax

EI Cancri3 traced

A pair of tiny red dwarfs in Cancer.SIMBAD, EI Cnc, M7V+M7V; worked out from its numbersRECONS, The One Hundred Nearest Star Systems (list as of 2012)Roman 1987, PASP 99, 695 (IAU constellation boundaries)
Spectral type M7V + M7V (SIMBAD).SIMBAD, GJ 1116
Its two stars are at magnitudes 13.93 and 13.75 (V), too faint to see with the naked eye.SIMBAD, GJ 1116 ASIMBAD, GJ 1116 BNASA Imagine the Universe, Ask an Astrophysicist

70 Ophiuchi3 traced

A pair of orange dwarf stars that orbit each other every 88 years, visible to the naked eye.Kaler, STARS: 70 OphiuchiSIMBAD, 70 Oph, V = 4.03
William Herschel found it to be double in 1779.W. Herschel, Catalogue of Double Stars (1782), second class no. 4, in Scientific Papers Vol. I (Dreyer ed., 1912)
Spectral type K0V + K4V (SIMBAD).SIMBAD, 70 Oph ASIMBAD, 70 Oph B

WISE 1506+70273 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, WISEP J150649.97+702736.0 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type T6 (SIMBAD).SIMBAD, WISE J150649.97+702736.1 (main name 2MASS J15065257+7027247)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.ESA Gaia Archive, Gaia DR3 gaia_source tableSIMBAD, WISE J150649.97+702736.1HyperPhysics, Stellar Parallax

GJ 33793 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 3379 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M3.5Ve (SIMBAD).SIMBAD, GJ 3379
At magnitude 11.31 (V) it is too faint to see with the naked eye.SIMBAD, GJ 3379NASA Imagine the Universe, Ask an Astrophysicist

DENIS J0817-61553 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, DENIS J081730.0-615520 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type T6 (SIMBAD).SIMBAD, DENIS J081730.0-615520 (main name 2MASS J08173001-6155158)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.ESA Gaia Archive, Gaia DR3 gaia_source tableSIMBAD, DENIS J081730.0-615520HyperPhysics, Stellar Parallax

Gliese 4453 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 445 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
A 2019 Gaia-based calculation has Voyager 1 passing within about 1.9 light-years of it in about 44,000 years; NASA's figures are 1.6 to 1.7 light-years in about 38,000 to 40,000 years.Bailer-Jones & Farnocchia 2019, RNAAS; worked out from its numbersarXiv version of Bailer-Jones & Farnocchia 2019NASA Voyager FAQ
Spectral type M4.0V (SIMBAD).SIMBAD, GJ 445

2MASS J0939-24483 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, 2MASS J09393548-2448279 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is a cold T dwarf, probably a close pair of brown dwarfs.Leggett et al. 2009, The Physical Properties of Four ~600 K T DwarfsJ-band periodicity in T8 dwarfs (2025)
Spectral type T8 (SIMBAD).SIMBAD, 2MASS J09393548-2448279

UCAC4 195-1191173 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, UCAC4 195-119117 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is an ultracool dwarf of type M7.Pérez Garrido et al. 2014, A&A 567, A6arXiv version of Pérez Garrido et al. 2014
Spectral type M7.0V (SIMBAD).SIMBAD, UCAC4 195-119117

GJ 33234 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 3323 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Two planets were reported around it in 2017; the discoverers called the outer one a candidate.NASA Exoplanet Archive, GJ 3323 overviewAstudillo-Defru et al. 2017, A&A 602, A88arXiv version of Astudillo-Defru et al. 2017
Spectral type M4.0Ve (SIMBAD).SIMBAD, GJ 3323
At magnitude 12.2 (V) it is too faint to see with the naked eye.SIMBAD, GJ 3323NASA Imagine the Universe, Ask an Astrophysicist

Wolf 4983 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, Wolf 498 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M2V (SIMBAD).SIMBAD, GJ 526
At magnitude 8.5 (V) it is too faint to see with the naked eye.SIMBAD, GJ 526NASA Imagine the Universe, Ask an Astrophysicist

Gliese 2513 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 251 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It has two known planets.NASA Exoplanet Archive, GJ 251 overview
Spectral type M3V (SIMBAD).SIMBAD, GJ 251

2MASS J1114-26183 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, 2MASS J11145133-2618235 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type T7.5 (SIMBAD).SIMBAD, 2MASS J11145133-2618235
Its distance comes from a measured parallax.SIMBAD, 2MASS J11145133-2618235

LP 816-603 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, LP 816-60 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M4V (SIMBAD).SIMBAD, LP 816-60
At magnitude 11.46 (V) it is too faint to see with the naked eye.SIMBAD, LP 816-60NASA Imagine the Universe, Ask an Astrophysicist

WISE 0350-56583 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, WISE J035000.32-565830.2 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is a Y dwarf, one of the coldest kinds of brown dwarf.Kirkpatrick et al. 2012, ApJ 753, 156arXiv version of Kirkpatrick et al. 2012
Spectral type Y1 (SIMBAD).SIMBAD, WISE J035000.32-565830.2

LSR J1835+32592 traced

An ultracool dwarf at the very bottom of the main sequence, with aurorae like a planet's.Hallinan et al. 2015, Nature 523, 568Hallinan et al. 2015, arXiv versionSIMBAD, LSR J1835+3259, M8.5V
Spectral type M8.5V (SIMBAD).SIMBAD, LSR J1835+3259

2MASS J0415-09353 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.SIMBAD, 2MASS J04151954-0935066 object type BD*, spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
It is a cold T dwarf of about 700 K, a standard for classifying late T dwarfs. In 2006 it was the coldest T dwarf known; colder ones have been found since.Burgasser et al. 2006, ApJarXiv version of Burgasser et al. 2006Diversity of Cold Worlds: 2MASS J0415-0935 with JWST (2025)Leggett et al. 2009
Spectral type T8 (SIMBAD).SIMBAD, 2MASSI J0415195-093506

Gliese 2053 traced

A red dwarf in Orion, at about magnitude 8.SIMBAD, GJ 205, M1.5Ve, V = 7.968; worked out from its numbersRoman 1987, PASP 99, 695 (IAU constellation boundaries)
Spectral type M1.5Ve (SIMBAD).SIMBAD, GJ 205
At magnitude 7.97 (V) it is too faint to see with the naked eye.SIMBAD, GJ 205NASA Imagine the Universe, Ask an Astrophysicist

Gliese 2294 traced

A red dwarf with a famous brown dwarf companion, Gliese 229 B, now known to be a close pair.Xuan et al. 2024, The cool brown dwarf Gliese 229 B is a close binaryBurgasser et al. 2000, ApJ 531, L57SIMBAD, GJ 229, M1V
Gliese 229 B, first imaged in 1994 and announced in 1995, was one of the first two brown dwarfs confirmed; Teide 1 was published weeks earlier.NASA/STScI, Astronomers Announce First Clear Evidence of a Brown Dwarf (29 Nov 1995); worked out from its numbersDiversity of Cold Worlds (2025), introductionCrossref record, Rebolo et al. 1995, Nature
In 2024 Gliese 229 B was found to be two brown dwarfs orbiting each other every 12 days.Xuan et al. 2024, NaturearXiv version of Xuan et al. 2024Caltech, It's Twins! Mystery of Famed Brown Dwarf Solved
Spectral type M1V (SIMBAD).SIMBAD, GJ 229

Alsafi3 traced

An orange dwarf star in Draco, a little smaller and cooler than the Sun, visible to the naked eye.Kaler, STARS: AlsafiSIMBAD, sig Dra, K0V, V = 4.68
Spectral type K0V (SIMBAD).SIMBAD, GJ 764
At magnitude 4.68 (V) it is visible to the naked eye.SIMBAD, GJ 764NASA Imagine the Universe, Ask an Astrophysicist

Ross 473 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, Ross 47 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M4V (SIMBAD).SIMBAD, GJ 213
At magnitude 11.51 (V) it is too faint to see with the naked eye.SIMBAD, GJ 213NASA Imagine the Universe, Ask an Astrophysicist

Gliese 5703 traced

A quadruple system: an orange dwarf, a pair of red dwarfs, and a distant cold brown dwarf, Gliese 570 D.Burgasser et al. 2000, ApJ 531, L57
Spectral type K4V (SIMBAD).SIMBAD, GJ 570
At magnitude 5.72 (V) its brightest star is just visible to the naked eye.SIMBAD, GJ 570NASA Imagine the Universe, Ask an Astrophysicist

Gliese 6933 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 693 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M3.5V (SIMBAD).SIMBAD, GJ 693
At magnitude 10.78 (V) it is too faint to see with the naked eye.SIMBAD, GJ 693NASA Imagine the Universe, Ask an Astrophysicist

Gliese 7543 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 754 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M4.5V (SIMBAD).SIMBAD, GJ 754
At magnitude 12.23 (V) it is too faint to see with the naked eye.SIMBAD, GJ 754NASA Imagine the Universe, Ask an Astrophysicist

BR Piscium3 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, BR Psc spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type dM1 (SIMBAD).SIMBAD, GJ 908
At magnitude 8.99 (V) it is too faint to see with the naked eye.SIMBAD, GJ 908NASA Imagine the Universe, Ask an Astrophysicist

Wolf 10553 traced

A red dwarf with a far fainter companion, VB 10, long one of the least massive stars known.Lalitha et al. 2019, CARMENES, HD 180617RECONS, The One Hundred Nearest Star Systems (list as of 2012)SIMBAD, VB 10, M8V
Spectral type M3-V (SIMBAD).SIMBAD, GJ 752
At magnitude 9.12 (V) it is too faint to see with the naked eye.SIMBAD, GJ 752NASA Imagine the Universe, Ask an Astrophysicist

Gliese 5883 traced

A red dwarf — a small, cool star far fainter than the Sun — one of the Sun's neighbours within 20 light-years.SIMBAD, GJ 588 spectral type and parallax; worked out from its numbersNASA Science, Types of Stars
Spectral type M2.5V (SIMBAD).SIMBAD, GJ 588
At magnitude 9.31 (V) it is too faint to see with the naked eye.SIMBAD, GJ 588NASA Imagine the Universe, Ask an Astrophysicist

Achird3 traced

A Sun-like star with an orange dwarf companion, visible to the naked eye in Cassiopeia.Kaler, STARS: AchirdSIMBAD, eta Cas, V = 3.44
Spectral type F9V (SIMBAD).SIMBAD, HD 4614 (eta Cas)
At magnitude 3.44 (V) it is easy to see with the naked eye.SIMBAD, HD 4614 (eta Cas)NASA Imagine the Universe, Ask an Astrophysicist

36 Ophiuchi3 traced

A triple star of three orange dwarfs in Ophiuchus.Jim Kaler, STARS: 36 Ophiuchi (University of Illinois); worked out from its numbersJim Kaler, STARS: introduction (class K colour, orange-yellow)SIMBAD, 36 Oph (K2V+K1V, Tokovinin 2006 reference)SIMBAD, 36 Oph C = V2215 Oph (K5V)
Spectral type K2V + K1V + K5V (SIMBAD).SIMBAD, 36 Oph ASIMBAD, 36 Oph BSIMBAD, GJ 664 (36 Oph C)
Its distance comes from a Gaia parallax: the tiny yearly shift in its position as the Earth circles the Sun.ESA Gaia Archive, Gaia DR3 gaia_source tableSIMBAD, 36 Oph BSIMBAD, 36 Oph AHyperPhysics, Stellar Parallax

YZ Canis Minoris3 traced

A young red dwarf flare star in Canis Minor.Bondar & Katsova 2019, Long-Term Cyclic Variability of YZ CMi; worked out from its numbersSIMBAD, YZ CMi (M4.0Ve)Roman 1987, IAU constellation boundaries, VizieR VI/42
Spectral type M4.0Ve (SIMBAD).SIMBAD, GJ 285
At magnitude 11.23 (V) it is too faint to see with the naked eye.SIMBAD, GJ 285NASA Imagine the Universe, Ask an Astrophysicist

Gliese 7833 traced

An orange dwarf in Sagittarius with a faint red dwarf companion, visible to the naked eye.Campante et al. 2026, EPRV Asteroseismology of the K dwarfs GJ 570 A and GJ 783 A; worked out from its numbersSIMBAD, HD 191408 = GJ 783 A (K2.5V, V = 5.32)SIMBAD, GJ 783 B (M3.5, Gaia G = 10.44)Roman 1987, IAU constellation boundaries, VizieR VI/42Jim Kaler, STARS: introduction (magnitude scale and the eye's limit)
Spectral type K2.5V (SIMBAD).SIMBAD, HD 191408
At magnitude 5.32 (V) it is visible to the naked eye in a dark sky.SIMBAD, HD 191408 (V from Zacharias et al. 2012, UCAC4)NASA Imagine the Universe, Ask an Astrophysicist: night sky

82 Eridani3 traced

A Sun-like star in Eridanus with several low-mass planets, visible to the naked eye.Nari et al. 2025, Revisiting the multi-planetary system of the nearby star HD 20794; worked out from its numbersSIMBAD, 82 Eri (e Eri, G6V, V = 4.27)Roman 1987, IAU constellation boundaries, VizieR VI/42Jim Kaler, STARS: introduction (magnitude scale and the eye's limit)
Spectral type G6V (SIMBAD).SIMBAD, HD 20794 (* e Eri); type from Keenan & McNeil 1989
At magnitude 4.27 (V) it is visible to the naked eye.SIMBAD, HD 20794 (* e Eri)NASA Imagine the Universe, Ask an Astrophysicist: night sky

QY Aurigae3 traced

A close pair of red dwarfs in Auriga.Winters et al. 2020, Spectroscopic Orbits of Eleven Nearby, Mid-to-Late M Dwarf Binaries; worked out from its numbersSIMBAD, GJ 268 = QY Aur (SB*, M4.5Ve)Roman 1987, IAU constellation boundaries, VizieR VI/42
Spectral type M4.5Ve (SIMBAD).SIMBAD, GJ 268 (V* QY Aur); type from Keenan & McNeil 1989
At magnitude 11.52 (V) it is too faint to see with the naked eye.SIMBAD, GJ 268 (V* QY Aur)NASA Imagine the Universe, Ask an Astrophysicist: night sky

WISE 1541-22502 traced

A brown dwarf — too light to shine like a star — one of the Sun's neighbours within 20 light-years.Kirkpatrick et al. 2021, The Field Substellar Mass Function Based on the Full-sky 20-pc Census; worked out from its numbersSIMBAD, WISE J154151.65-225024.9 (BD*, parallax 166.9 +/- 2.0 mas)NASA Science, Types of stars: brown dwarfs
It is a Y dwarf, one of the coldest kinds of brown dwarf.Kirkpatrick et al. 2011, ApJS 197, 19Kirkpatrick et al. 2011, the same paper free to read (arXiv)Cushing et al. 2011, ApJ 743, 50Cushing et al. 2011, the same paper free to read (arXiv)SIMBAD, WISEP J154151.66-225025.2

Delta Pavonis3 traced

One of the nearest Sun-like stars, a little older than the Sun and starting to swell into a subgiant.Porto de Mello et al. 2006, Astrobiologically Interesting Stars Within 10 Parsecs of the SunJim Kaler, STARS: Delta Pavonis (University of Illinois)
Spectral type G8IV (SIMBAD).SIMBAD, HD 190248 (* del Pav); type from Gray et al. 2006
At magnitude 3.56 (V) it is well within naked-eye range.SIMBAD, HD 190248 (* del Pav)NASA Imagine the Universe, Ask an Astrophysicist: night sky

SIMP 0136+09333 traced

A young brown dwarf of about planetary mass, with weather and aurorae.Nasedkin et al. 2025, A&A, The JWST weather report: SIMP-0136Gagné et al. 2017, SIMP J013656.5+093347 Is Likely a Planetary-mass Object in the Carina-Near Moving GroupArtigau et al. 2009, Photometric Variability of the T2.5 Brown Dwarf SIMP J013656.5+093347Kao et al. 2016, Auroral Radio Emission from Late L and T Dwarfs
Its brightness changes as it rotates every 2.4 hours, turning atmospheric features into view: patchy clouds, hot spots and changing chemistry.Artigau et al. 2009, ApJ 701, 1534Artigau et al. 2009, the same paper free to read (arXiv)McCarthy et al. 2025, ApJL 981, L22McCarthy et al. 2025, the same paper free to read (arXiv)Nasedkin et al. 2025, A&A (JWST Weather Report)Nasedkin et al. 2025, the same paper free to read (arXiv)
Spectral type T2.0 (SIMBAD).SIMBAD, SIMP J013656.5+093347.3; type from Burgasser et al. 2010, ApJ

Moons and dwarf planets30 traced

The largest body in the asteroid belt — a dwarf planet, visited by Dawn.NASA Science, Ceres
Spins every four hours, stretched into an egg; it has a ring. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.NASA Science, Haumea factsRabinowitz et al. 2006, ApJ 639, 1238
A reddish dwarf planet of the Kuiper belt, found in 2005. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.NASA Science, Makemake facts
Almost Pluto's size and more massive; its discovery is why Pluto was reclassified. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.M. Brown, Caltech, Eris pageSicardy et al. 2011, Nature 478, 493NASA Science, Eris facts
A likely dwarf planet whose ring lies far outside the distance where a ring should clump into a moon (Morgado et al. 2023). Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.Morgado et al. 2023, Nature 614, 239
On almost the same orbit as Pluto. Its moon Vanth is about half its size. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.Brown et al. 2010, AJ; worked out from its numbersSickafoose et al. 2019, Icarus 319, 657JPL Small-Body Database, Orcus
Among the largest worlds beyond Neptune and one of the reddest, on a long orbit tilted 31°. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.Brown et al. 2011, ApJKiss et al. 2019, IcarusJPL Small-Body Database, Gonggong
Never comes nearer the Sun than 76 au, far beyond Neptune's pull, and takes more than 10,000 years to go round. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.JPL Small-Body Database, Sedna; worked out from its numbersBrown et al. 2004, ApJ
Rounds Mars three times a day, slowly spiralling in.NASA Science, Phobos
Mars's smaller, outer moon, 12 km across.NASA Science, DeimosNASA NSSDCA, Mars Fact Sheet
The most volcanic body known, heated by Jupiter's tides.NASA Science, Io facts
Very likely a salty ocean under its ice shell (Galileo's magnetometer found the signs) — perhaps more than twice the water in all Earth's oceans.NASA Science, Europa: evidence for an oceanNASA Science, Europa Clipper
The largest moon in the Solar System, bigger than Mercury.NASA Science, Ganymede
The most heavily cratered surface known.NASA Science, Callisto
One crater, Herschel, is a third of its width.NASA Science, Mimas
Geysers of salty water from its south pole feed Saturn's E ring.NASA Science, Enceladus
Almost pure water ice.NASA Science, Tethys
Bright ice cliffs score its surface.NASA Science, DioneNASA Photojournal PIA06163
Saturn's second-largest moon.NASA Science, Rhea
A thick orange atmosphere over lakes of liquid methane and ethane; Huygens landed there in 2005.NASA Science, Titan factsESA, Cassini-Huygens factsheet
One face coal-dark, the other ten to twenty times brighter.NASA Science, Iapetus; worked out from its numbers
Patched together, with cliffs up to 20 km tall. The part of it never seen up close is an artist's impression.NASA APOD, 2016 Nov 27, Verona RupesNASA Science, Miranda
The brightest of Uranus's big moons. The part of it never seen up close is an artist's impression.NASA Science, ArielNASA NSSDCA, Uranian Satellite Fact Sheet
The darkest of Uranus's big moons. The part of it never seen up close is an artist's impression.NASA Science, Umbriel
Uranus's largest moon. The part of it never seen up close is an artist's impression.NASA Science, Titania
The outermost of Uranus's big moons. The part of it never seen up close is an artist's impression.NASA NSSDCA, Uranian Satellite Fact Sheet
Goes round Neptune backwards — probably a captured Kuiper belt world; it has active geysers. The part of it never seen up close is an artist's impression.NASA Science, Triton
One of the darkest objects in the Solar System. Artist's impression: it has been photographed, but not mapped here. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.NASA Science, Proteus
On one of the most eccentric moon orbits known. Artist's impression: its surface hasn't been observed up close yet. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.NASA Science, Nereid
Half Pluto's size; the two always keep the same face to each other. The part of it never seen up close is an artist's impression.NASA Science, Charon

Planets, in a line11 traced

Our star: more than 99.8% of the Solar System's mass, 4.6 billion years old.NASA Science, Sun facts
The smallest planet and the nearest the Sun; its year is 88 days.NASA Science, Mercury factsNASA NSSDCA, Mercury Fact Sheet
Wrapped in sulphuric-acid cloud over a surface of about 465 °C — the hottest planet.NASA Science, Venus factsNASA NSSDCA, Venus Fact Sheet
Home. The only world known to have life.NASA Science, Earth
Rusted dust over old riverbeds; Olympus Mons is more than twice Everest's height.NASA Science, Mars facts
More than twice the mass of every other planet together.NASA Science, Jupiter facts
Its main rings are about 270,000 km across and typically only about ten metres thick.NASA Science, Saturn facts; worked out from its numbersNASA NSSDCA, Saturnian Rings Fact Sheet
An ice giant tipped on its side: its axis lies 98° from upright.NASA NSSDCA, Uranus Fact SheetNASA Science, Uranus facts
The first planet found by mathematical prediction (1846); its winds are the fastest in the Solar System.NASA Science, Neptune facts
A dwarf planet of nitrogen ice and mountains of water ice, seen by New Horizons in 2015. The part of it never seen up close is an artist's impression.NASA Science, Pluto facts
About 384,000 km away, drifting off by 3.8 cm a year.NASA NSSDCA, Moon Fact Sheet

Home card6 traced

Its light takes 8 minutes to reach the EarthNASA Science, Earth
4.2 years to reach the nearest star, Proxima CentauriNASA Exoplanet Archive, Proxima Cen system distance; worked out from its numbersESO press release eso1629
A pioneering commercial radio broadcast, from Pittsburgh in 1920IEEE Milestone, Westinghouse Radio Station KDKA, 1920
The Sun is about 27,000 light-years from the centre of the Milky WayGRAVITY Collaboration 2019, A&A 625, L10; worked out from its numbers
in a small arm called the Orion SpurNASA Science, The Milky Way Galaxy
goes round once every ~230 million yearsNASA StarChild, orbit of the Sun; worked out from its numbers

What each kind of object is12 traced

An emission nebula — a cloud of gas lit from within by the young, hot stars born in it.NASA Hubble, Hubble's Nebulae
A reflection nebula — dust lit by the starlight it scatters, which is why it looks blue.NASA Hubble, Hubble's Nebulae
A dark nebula — a cloud of dust thick enough to blot out the stars behind it.NASA Hubble, Hubble's Nebulae
A planetary nebula — the shell a dying Sun-like star threw off, lit by the white dwarf it left.ESA/Hubble, Planetary NebulaNASA Hubble, Hubble's Nebulae
A supernova remnant — the wreckage of an exploded star, still racing outward.NASA Hubble, Hubble's NebulaeNASA Imagine, Supernova Remnants
An open cluster — stars born together from one cloud, slowly drifting apart.NASA Hubble, Hubble's Star Clusters
A globular cluster — thousands to millions of ancient stars packed into a ball.NASA Hubble, Hubble's Star ClustersESA/Hubble, Globular cluster
A galaxy — thousands to trillions of stars held by gravity, like our own Milky Way.NASA Science, Galaxies
A black hole — matter so dense that not even light gets out.NASA Science, Black Holes
A neutron star — the collapsed core of an exploded star, a Sun's mass the size of a city.NASA Imagine, Neutron Stars
A white dwarf — the bare, cooling core of a star like the Sun, about the size of the Earth.NASA Science, Star Types
A brown dwarf — too heavy to be a planet, too light to shine like a star.NASA Science, Star Types

Spacecraft77 traced

NASA/ESA/CSA, since 2022-01-24NASA Webb mission page
Operating (ESA news through 19 October 2026). Orbits the Sun–Earth L2 point.ESA Euclid mission pageJPL Horizons object data, Euclid
ESA, since 2023-07-01JPL Horizons object data, Euclid
Active mission (science.nasa.gov, page updated 2026-01-09). Orbits the Sun–Earth L1 point, ~1.5 million km sunward.NASA SOHO mission page
ESA/NASA, since 1996-02-14NASA SOHO mission page
Operating — NOAA's primary solar-wind source since June 2026, with ACE as backup (NOAA SWPC notice, 2026-06-30). Orbits the Sun–Earth L1 point.NOAA SWPC notice, Solar Wind Data and Display Changes, 2026-06-30NOAA SWPC notice, SOLAR-1 CCOR-2 now fully operational, 2026-07-23NOAA SWPC real-time solar wind feed, read 2026-11-01
NOAA/NASA, since 2026-01-23NOAA NESDIS, SOLAR-1 page
Operating — arrived at L1 in January 2026, science since February 2026 (NASA); its real-time I-ALiRT data was in NOAA's feed on 2026-10-29. Maps the heliosphere's edge from the Sun–Earth L1 point.NASA IMAP blog archive (posts of 2026-01-12, 2026-02-02, 2026-08-07)NASA IMAP blog, new data release, 2026-08-07NOAA SWPC real-time solar wind feed, read 2026-11-01
NASA, since 2026-01-10NASA IMAP blog archive, post of 2026-01-12
Operating — NOAA's backup solar-wind source behind SOLAR-1 (NOAA SWPC notice, 2026-06-30); its real-time data was flowing on 2026-11-01, when NOAA's feed marked it the active source. At the Sun–Earth L1 point since 1997.NOAA SWPC notice, Solar Wind Data and Display Changes, 2026-06-30NOAA SWPC real-time solar wind feed, read 2026-11-01
NASA, since 1997-12-12JPL Horizons object data, ACE
Operating — JPL's Wind trajectory was revised 2026-09-30 and runs to December 2026 (Horizons). Launched 1994; at the Sun–Earth L1 point since 2004.JPL Horizons object data, WindNASA Wind mission page
NASA, since 2004JPL Horizons object data, WindNASA Wind project siteNASA Wind mission page
Active (extended into 2029 by NASA's 2026 Heliophysics Senior Review); perihelia ~6.2 million km from the Sun every 88 days.NASA Parker Solar Probe blog, 2026-09-10JPL Horizons object data, Parker Solar ProbeNASA Parker mission page
NASA/JHUAPL, since 2018-08-12NASA Parker mission page
Operating (ESA news through 8 October 2026).ESA Solar_Orbiter mission page
ESA/NASA, since 2020-02-10JPL Horizons object data, Solar Orbiter
Arriving at Mercury: orbit insertion planned for 2026-11-21, science from April 2027 (ESA, 2026).ESA BepiColombo factsheet
ESA/JAXA, since 2018-10-20ESA BepiColombo mission page
In cruise; Earth flyby September 2026 done, next Earth flyby January 2029, Jupiter July 2031 (ESA, October 2026).ESA Juice mission pageJPL Horizons object data, Juice
ESA, since 2023-04-14JPL Horizons object data, Juice
Active mission, in cruise; Earth flyby 2026-12-03, Jupiter April 2030 (science.nasa.gov, page updated 2026-09-10).NASA Europa Clipper mission page
NASA/JPL-Caltech, since 2024-10-14NASA Europa Clipper mission page
Active mission, cruising to the asteroid Psyche after its Mars flyby; arrival 2029 (science.nasa.gov, page updated 2026-10-22).NASA Psyche mission page
NASA/JPL-Caltech, since 2023-10-13NASA Psyche mission page
Active — OSIRIS-REx, renamed after delivering Bennu's sample, now bound for Apophis: Earth flyby 2025-09-23, rendezvous June 2029, two months after Apophis passes the Earth (science.nasa.gov, updated 2026-09-23).NASA OSIRIS-APEX mission pageNASA OSIRIS-REx blog, 2023-09-24
NASA, since 2023-09-24NASA OSIRIS-REx blog, 2023-09-24
Operating on its extended mission — flew past the asteroid Torifune (2001 CC21) on 2026-07-05; Earth swing-bys in 2027 and 2028, then the 11-metre asteroid 1998 KY26 in 2031 (JAXA).ISAS/JAXA Hayabusa2 pageJPL Horizons object data, Hayabusa2Hayabusa2# target 1998 KY26 preview, EPSC-DPS 2025
JAXA, since 2020-12-06ISAS/JAXA Hayabusa2 pageJAXA global Hayabusa2 page
Retired 2025-03-27 after mapping nearly two billion stars; switched off and sent from L2 into its own orbit round the Sun (ESA).ESA, Farewell Gaia
ESA, since 2025-03-27ESA, Farewell Gaia
Out of fuel: NASA announced its retirement on 2018-10-30 and sent its last commands on 2018-11-15, after finding thousands of planets round other stars; it trails the Earth round the Sun (NASA).NASA, Goodnight Kepler, 2018-11-16NASA release 18-092JPL Horizons object data, Kepler
NASA, since 2018-11-15NASA, Goodnight Kepler, 2018-11-16
Retired 2020-01-30 after 16 years of infrared astronomy; it trails the Earth round the Sun. Its position since then is JPL's long-term prediction — nobody tracks it now (NASA/JPL).NASA Spitzer mission pageJPL Horizons object data, Spitzer
NASA, since 2020-01-30NASA Spitzer mission page
A car, not a working spacecraft: it has a mannequin at the wheel, launched as the dummy payload of the first Falcon Heavy (2018-02-06), on an orbit round the Sun out to about 1.67 au, just past Mars. JPL's trajectory is fitted to telescope sightings from February and March 2018 (JPL Horizons).JPL Horizons object data, Tesla Roadster; worked out from its numbersNASA NSSDCA Mars fact sheet
SpaceX, since 2018-02-06JPL Horizons object data, Tesla Roadster
Active mission; next flyby the Trojan asteroid Eurybates on 2027-08-11 (science.nasa.gov, page updated 2026-09-08).NASA Lucy mission page
NASA, since 2021-10-16NASA Lucy mission page
Active — "The STEREO-A spacecraft remains active" (science.nasa.gov, page updated 2025-12-12); JPL's trajectory is fitted to tracking through 2026-10-29 (Horizons, read 2026-11-04). It circles the Sun near the Earth's orbit, watching the Sun. Its twin, STEREO-B, went silent in 2014.NASA STEREO mission pageJPL Horizons object data, STEREO-A
NASA, since 2006-10-26NASA STEREO mission page
Mission over on 2009-06-30, after flying over the Sun's poles: its last commands went up and the ground station then found no carrier, "confirming that the transmitter was switched off on the spacecraft" (ESA status log). An ESA-built craft on a joint ESA/NASA mission. It still circles the Sun, and nobody tracks it: its position since 2009-06-29 is JPL's prediction (Horizons).ESA Ulysses mission status reports, June 2009ESA Ulysses overviewJPL Horizons object data, Ulysses
ESA/NASA, since 1990-10-06NASA Ulysses mission page
Mission over — it missed its contacts on 2018-10-31 and 11-01, its hydrazine believed gone. It is silent in orbit round Ceres, where it arrived on 2015-03-06. Nobody tracks it: its position since 2018-10-31 is JPL's prediction, which leaves out whatever Dawn's last moments did to its orbit (Horizons).JPL Horizons object data, DawnNASA release, Dawn mission comes to endNASA Dawn mission status
NASA/JPL-Caltech, since 2015-03-06NASA Dawn mission status
Active, on its extended mission (science.nasa.gov, page updated 2026-08-13). Hunts planets round nearby stars from an orbit of about 13.7 days, in step with the Moon: nominally 108,400 × 376,300 km, the mission design as Horizons' summary gives it.NASA TESS mission pageJPL Horizons object data, TESS
NASA, since 2018-04-18NASA TESS mission page
Active mission (science.nasa.gov, page updated 2026-04-14), on a reduced budget: $63M for FY26, $11M below full-mission costs (Chandra Users' Committee, 2026-05-06). Its orbit has changed since launch, when it was 10,000 × 140,161 km, inclined 28.5° (chandra.harvard.edu); about 12,800 × 136,000 km above the Earth, inclined 58°, from CelesTrak's elements read 2026-10-31.NASA Chandra mission page; worked out from its numbersSlane, Chandra Users' Committee, May 2026Chandra specificationsCelesTrak elements for Chandra, read 2026-11-01
NASA/SAO, since 1999-07-23NASA Chandra mission page
Active mission — launched 2026-08-30 on a Falcon Heavy (science.nasa.gov), in science commissioning by 2026-10-22 (NASA's Roman blog). On its way to the Sun–Earth L2 point: NASA's plan is final orbit there about 100 days after launch, about early December (Roman blog, 2026-09-14); no word of its arrival was found on 2026-10-31. JPL's trajectory is tracking through 2026-10-18, a prediction after (Horizons).NASA Roman mission pageNASA Roman blog, 2026-10-22NASA Roman blog, 2026-09-14JPL Horizons object data, Roman
NASA, since 2026-08-30NASA Roman mission pageJPL Horizons object data, Roman
Active by NASA's listing: THEMIS-ARTEMIS is an "Active Mission" with two craft round the Moon (science.nasa.gov, page updated 2026-08-11), though that page does not name P1 or P2. JPL's trajectory rests on tracking through 2026-10-15 (Horizons, revised 2026-10-20), so someone was tracking it then. One of five THEMIS craft launched in 2007, sent on to the Moon, in orbit since 2011.NASA THEMIS mission pageJPL Horizons object data, ARTEMIS-P1
NASA/UC Berkeley, since 2011-06-27JPL Horizons object data, ARTEMIS-P1NASA release, two probes tackle new mission
NASA/UC Berkeley, since 2011-07-17JPL Horizons object data, ARTEMIS-P2NASA release, two probes tackle new mission
Operating — NASA reported a close pass of Thebe on 2026-05-01 and new Io results in July 2026 (science.nasa.gov/mission/juno, checked 2026-10-26). Its funded extension ran to September 2025.NASA Photojournal, Juno captures Thebe (2026-05-05)NASA Photojournal, Mapping Io's Hidden Heat (2026-07-22)NASA, Juno mission page
Active mission (science.nasa.gov, page updated 2026-09-03).NASA, Mars Reconnaissance Orbiter mission page
NASA/JPL-Caltech, since 2006-03-10NASA, Mars Reconnaissance Orbiter mission page
NASA/JPL-Caltech, since 2001-10-24NASA, 2001 Mars Odyssey mission page
ESA, since 2003-12-25NASA, Mars Express mission pageESA, Mars Express
NASA, since 2009-06-23NSSDCA Master Catalog, LRONASA, LRO mission page
NASA/ESA, since 1990-04-24ESA, Hubble overviewNASA, Hubble mission page
Crewed and operating.NASA, International Space Station
NASA/JPL-Caltech, since 2016-07-04NASA, Juno mission page
Active mission (science.nasa.gov, checked 2026-11-01).NASA, LRO mission page
Active mission (science.nasa.gov, checked 2026-11-01).NASA, Hubble mission page
Active mission (science.nasa.gov, checked 2026-11-01). Orbits the Sun–Earth L2 point, ~1.5 million km beyond Earth.NASA, Webb mission page
Operating — ISRO's third guest-observer cycle runs October–December 2026 (ISRO announcement, 2026-07-16). India's solar observatory at the Sun–Earth L1 point.ISRO, Aditya-L1 Announcement of Opportunity (third cycle), 16 July 2026ISRO Science Programme Office, Aditya-L1 AO third cycle (PDF), July 2026ISRO, Aditya-L1 mission page
ISRO, since 2024-01-06ISRO, Aditya-L1 mission pageISRO, Aditya-L1 AO third cycle (PDF), July 2026
Active mission (science.nasa.gov, page updated 2026-06-22) — the longest-serving spacecraft at another planet. NASA put its remaining propellant at about 4 kg in 2023.NASA Science, 2001 Mars Odyssey mission page (updated 22 June 2026)NASA, Engineers Keep an Eye on Fuel Supply of NASA's Oldest Mars Orbiter, 15 March 2023
Operating; funded to the end of 2026 with an extension to 2029 requested (ESA, EPSC 2026 abstract, September 2026).Wilson (ESA/ESTEC), Europe's Mars orbiters: Status & Highlights, EPSC2026-270, Sept 2026
Operating; spacecraft health nominal (ESA, EPSC 2026 abstract, September 2026).Wilson (ESA/ESTEC), Europe's Mars orbiters: Status & Highlights, EPSC2026-270, Sept 2026
ESA, since 2016-10-19ESA press release, ExoMars TGO reaches Mars orbit while EDM situation under assessment, 19 Oct 2016Wilson (ESA/ESTEC), EPSC2026-270
Operating; in an extended phase through 2028 (UAE Space Agency, quoted by NYU Abu Dhabi, June 2026).NYU Abu Dhabi, agreement with the UAE Space Agency on the Emirates Mars Mission (June 2026)
UAE Space Agency / MBRSC, since 2021-02-09LASP (CU Boulder), EMM / Hope mission pageLASP, New Emirates Mars Mission observations hint at the origins of Mars' mysterious moon, 25 Apr 2023
Reported operating: ISRO's mission page says the orbiter is healthy in a 100 km polar orbit, but the page is undated; ISRO reported new results from its radar on 2026-05-27. No later official update found.ISRO, Chandrayaan-2 science pageISRO, Chandrayaan-2 mission pageISRO, Chandrayaan-2 DFSAR observations reveal subsurface ice in lunar south polar regions, 27 May 2026
ISRO, since 2019-08-20ISRO, Chandrayaan-2 mission pageISRO, Chandrayaan-2 science page
NASA/Roscosmos/ESA/JAXA/CSA, since 1998-11-20NASA, Zarya ModuleNASA, International Space Station Facts and Figures

Spacecraft left out4 traced

Lost: contact ended 2025-12-06 and NASA declared the mission over in 2026.NASA release 26-047, 2026-06-03
Horizons carries a trajectory into 2027, fitted to tracking through late October 2026 (read 2026-11-04), but no 2026 mission status could be confirmed from KARI/KASA.JPL Horizons object data, Danuri
Still returning images: NASA's EPIC camera on it has dates through 2026-10-29, after a gap from 2025-07-15 to 2025-10-09. NOAA stopped using its solar-wind data on 2026-06-30, when SOLAR-1 took over (NOAA SWPC).NOAA SWPC notice, Solar Wind Data and Display Changes, 2026-06-30NASA EPIC image archive API, read 2026-11-01JPL Horizons object data, DSCOVR
A lander, not an orbiter — retired December 2022; see lib/ouranosSurfaceSites.NASA InSight mission page

Spacecraft sizes28 traced

13.2 m long (NASA), 4.2–4.3 m across at the widest (ESA; NASA). Model: 13.35 m tube (source units are inches).NASA, About HubbleESA/Hubble fact sheet
Sunshield 21.197 × 14.162 m (NASA). Model sunshield: 21.0 × 12.9 m (source in metres).NASA Webb, sunshield page
"356 feet (109 meters) end-to-end"; solar arrays "239 feet … (73 meters)" (NASA facts and figures). Model: 98.3 m along the truss with its arrays as posed, 73.3 m across the arrays (source units are inches).NASA, Space Station Facts and Figures
13 m magnetometer boom, 3.7 m high-gain antenna (NASA). Model: ~3.7 m dish, 16.9 m bounding span (source in metres).NSSDCA, Voyager 1NASA, Voyager spacecraft
Body ~0.7 × 2.1 × 2.7 m, high-gain antenna 2.1 m (NASA). Model: 2.10 m dish, 2.75 m body (source: inches at 1:20).NSSDCA, New HorizonsJHU APL, New Horizons spacecraft
"more than 66 feet (20 meters)" across its three arrays; arrays 9 × 2.65 m (NASA/JPL). Model: 2.4 m dish, 17.7 × 18.5 m bounding box of the three-wing star (source in metres).NASA/JPL, Juno launch press kit, 2011
Heat shield about 7.5 feet (2.3 m) across (JHU APL). Model in metres; 6.6 m bounding box includes the magnetometer boom and FIELDS whips.JHU APL, Parker Solar Probe spacecraftNSSDCA, Parker Solar Probe
13.6 m across the deployed arrays, 6.5 m tall incl. the 3 m dish (NASA launch press kit, 2005). Model: 13.18 m (source in metres).NASA/JPL, MRO launch press kit, 2005
"37.5 feet (11.4 meters)" long; HGA 2 m (NASA). Model: 2.0 m dish, but 13.1 m across the arrays (source in metres).NASA, MAVEN mission page
30.5 m across the solar arrays, 3 m high-gain antenna (NASA). Model: 30.50 m and a 3.0 m dish (source in metres).NASA/JPL, Europa Clipper press kit (archived copy)NASA, Europa Clipper mission page
High-gain antenna 2.74 m (NASA). Model: 2.74 m dish (source in metres).NSSDCA, Pioneer 10
6.7–6.8 m tall, 4 m high-gain antenna, 11 m magnetometer boom (NASA). Model: 4.0 m dish (source in metres).NASA/JPL, Cassini launch press kit, 1997 (archived copy)NASA, Cassini quick factsNASA, Cassini magnetometer
3 m long, 2.7 m wide, 2.2 m tall (NASA). Model: 3.11 × 2.70 m, 1.84 m tall with the mast stowed (source in metres).NASA, Perseverance rover components
The bus is 2.2 m long, 1.7 m tall and 2.6 m wide; the gamma-ray spectrometer sits on a 6.2 m boom (NASA). Model (source in metres): bus 2.2 × 1.5 m, array 5.67 m across, the boom ~4.8 m — shorter than NASA's figure.NASA/JPL, Mars Odyssey arrival press kit, 2001
9.5 m across the solar panels; 4.3 × 2.7 × 3.7 m body (ESA). Model scaled by its panels (43.27 units = 9.5 m): body 3.8 × 3.2 m.SOHO Fact Sheet (ESA/NASA)ESA, SOHO overview
About 4 m (13 ft) tall (JPL, Spitzer quick facts). Model (source in metres): 4.47 m tall, 2.1 m across.NASA/JPL, Spitzer press kit, quick facts, 2020 (archived copy)
Body 1.6 m across and 1 m high, not counting the four solar arrays and the magnetometer booms (NASA/Caltech ACE mission overview). Model: scaled by the 1.6 m octagon; its deck then measures 0.92 m.Caltech, ACE mission overview
A drum 2.4 m across and 2 m tall (JPL's Mission and Spacecraft Library); NSSDCA gives about 2.8 m across and 1.25 m high. Model: scaled by the 2.4 m drum.JPL Mission and Spacecraft Library, Wind (archived copy)NSSDCA, Wind
6.2 m across its deployed solar arrays; the bus 3.2 m high, 2.4 m wide (NASA Scientific Visualization Studio, svs.gsfc.nasa.gov/20258). Model scaled by its arrays (34.65 units = 6.2 m): bus ~1.9 m wide.NASA SVS 20258
19.7 m across its solar arrays (JPL, Dawn at Vesta press kit, 2011; NASA's Dawn spacecraft page rounds it to "65 feet (20 meters)"), body 1.64 × 1.27 × 1.77 m (NASA). Model (source in metres): 19.70 m.NASA/JPL, Dawn at Vesta press kit, 2011 (archived copy)NASA/JPL, Dawn launch press kit
"13.8 m x 19.5 m" with the solar arrays deployed (chandra.harvard.edu). Model (source in metres): 13.78 × 19.51 m.Chandra X-ray Center, specifications
"Hexagonal 3.9 x 1.2 x 1.5 meter dimensions when fully deployed" (JPL Horizons' header for -95, read 2026-10-31). The source measures 7.39 × 3.10 × 3.06 and was built at a half, from an earlier 3.7 m figure, which gives 3.70 m across the arrays, about 5% short, and 1.53–1.55 m the other ways, against the 1.2 and 1.5 m.JPL Horizons, object data for -95
6.47 × 2.03 m with the solar arrays deployed, 1.14 × 1.22 m at launch (JPL Horizons' header for -234). The file has no units: scaled by its arrays (3142 units = 6.47 m), which leaves the body 1.04 × 0.98 × 1.42 m, smaller than those figures.JPL Horizons, object data for -234
Body 84 × 84 × 51 cm (eoPortal). Model (source in metres): 0.88 × 0.88 × 0.52 m; 4.3 m across its two magnetometer booms.eoPortal, THEMIS
3.9 × 2.7 × 2.6 m in launch configuration (NASA LRO/LCROSS press kit, 2009: 152 × 108 × 103 inches stowed). Model: 3.66 m tall bus stack, 5.5 m with the array deployed (source in metres).NASA, LRO/LCROSS launch press kit, May 2009 (LRO Quick Facts, p. 6), hosted by the LROC team
4.7 m tall, 2.7 m across (NASA Kepler launch press kit, 2009). Model (source in metres): 5.0 × 2.65 m.NASA/JPL, Kepler launch press kit, February 2009 (Spacecraft: Dimensions)
Body 3.2 × 3.3 × 2.1 m with booms stowed; axial antenna 7.5 m, radial wire antenna 72.5 m, magnetometer boom 5.6 m, dish 1.65 m (ESA Ulysses datasheet). Model (taken as metres): wire 68.0 m, axial antenna 8.9 m, dish 1.46 m, so its parts do not share one scale and it was not rescaled. The 7.5 m is the axial antenna; the wire is too thin to frame the craft by.ESA, Ulysses datasheet
"over 42 feet (12.7 meters) long", "more than 14 feet (4.4 meters) wide when fully deployed", mirror 2.4 m (NASA). The file has no units: scaled so the telescope's body is 4.4 m across, which leaves it 11.6 m long, its inner tube about 2.45 m across, and its array 6.98 m wide, wider than NASA's 4.4 m.NASA Science, Roman Space Telescope FAQ

Landing sites64 traced

Tranquility Base — the first people on another world.NSSDCA, Apollo 11NASA, Apollo 11
NASA, 1969-07-20. historic siteNSSDCA, Apollo 11
Landed beside Surveyor 3 in the Ocean of Storms.NSSDCA, Apollo 12NSSDCA, Surveyor 3
NASA, 1969-11-19. historic siteNSSDCA, Apollo 12
Fra Mauro highlands.NASA, Apollo 14NSSDCA, Apollo 14
NASA, 1971-02-05. historic siteNSSDCA, Apollo 14
Hadley–Apennine; the first Lunar Roving Vehicle.NSSDCA, Apollo 15NASA, Apollo 15
NASA, 1971-07-30. historic siteNSSDCA, Apollo 15
The Descartes highlands.NASA, Apollo 16NSSDCA, Apollo 16
NASA, 1972-04-21. historic siteNSSDCA, Apollo 16
Taurus–Littrow — the last time people walked on the Moon.NASA, Apollo 17NSSDCA, Apollo 17
NASA, 1972-12-11. historic siteNSSDCA, Apollo 17
A Chinese lander and rover, in Mare Imbrium.LROC, Chang'e 3 Lander and Rover From Above
CNSA, 2013-12-14. landed with the Yutu rover; operating status not verifiedLROC, Chang'e 3 Lander and Rover From Above
The first landing on the Moon's far side, in Von Kármán crater.Wang et al. 2024, National Science Review 11, nwad329 (PMC10880881)LROC, First Look: Chang'e 4
CNSA, 2019-01-03. landed with the Yutu-2 rover; operating status not verifiedLROC, First Look: Chang'e 4Li et al. 2019, Nature
Brought 1.7 kg of Moon rock home from Oceanus Procellarum.Wang et al. 2024, National Science Review 11, nwad329 (PMC10880881)LROC, First Look: Chang'e 5
CNSA, 2020-12-01. sample-return landerLROC, First Look: Chang'e 5
The first samples from the far side, in the Apollo basin.National Science Review paper on the CE6 samples (PMC13455602)LROC, First Look: Chang'e 6
CNSA, 2024-06-01. sample-return landerLROC, First Look: Chang'e 6The Planetary Society, Chang'e-6 (CNSA, China's space agency, runs its lunar programme)
The first American soft landing on the Moon.NSSDCA, Surveyor 1
NASA, 1966. historic siteNSSDCA, Surveyor 1
Apollo 12's crew walked over to it and brought pieces of it home.NSSDCA, Surveyor 3NASA, Surveyor 3
NASA, 1967. historic siteNSSDCA, Surveyor 3NASA, Surveyor 3
Measured what the Moon's soil is made of, in Mare Tranquillitatis.NSSDCA, Surveyor 5
Fired its engines and hopped: the first rocket lift-off from the Moon.NSSDCA, Surveyor 6
The last Surveyor, in the highlands near the crater Tycho.NASA, Surveyor 7NSSDCA, Surveyor 7
NASA, 1968. historic siteNASA, Surveyor 7
The first robot to bring Moon rock back to Earth.Siddiqi, Beyond Earth (NASA SP-2018-4041)
USSR, 1970. historic siteNSSDCA, Soviet lunar missionsSiddiqi, Beyond Earth (NASA SP-2018-4041)
Carried Lunokhod 1, the first rover on another world.Siddiqi, Beyond Earth (NASA SP-2018-4041)NSSDCA, Soviet lunar missions
Where the first rover on another world stopped.Siddiqi, Beyond Earth (NASA SP-2018-4041)
USSR, 1970. where it stoppedSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)LROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
Brought back samples from the highlands.Siddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)
USSR, 1972. historic siteSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)NSSDCA, Soviet Lunar Missions
Carried Lunokhod 2, in the crater Le Monnier.Siddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)NSSDCA, Soviet Lunar Missions
USSR, 1973. historic siteSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)NSSDCA, Soviet Lunar Missions
Where the second Soviet rover stopped.Siddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)LROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
USSR, 1973. where it stoppedSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)
Damaged on landing in Mare Crisium, so it could not drill.Siddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)
USSR, 1974. historic siteSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)NSSDCA, Soviet Lunar Missions
Finished Luna 23's job, close by: the last Moon samples for 44 years.Siddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA); worked out from its numbersNSSDCA, Chronology of Lunar Missions
USSR, 1976. historic siteSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)NSSDCA, Soviet Lunar Missions
Hit the Moon as planned, but its cameras failed and sent back no pictures.NSSDCA, Ranger 6
NASA, 1964. crater left by its impactNSSDCA, Ranger 6LROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
Sent America's first close-up pictures of the Moon, right up to impact.NASA, Ranger 7NSSDCA, Ranger 7
Photographed the Sea of Tranquillity on its way down.NSSDCA, Ranger 8
NASA, 1965. crater left by its impactNSSDCA, Ranger 8LROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
Its last pictures, of the crater Alphonsus, went out live on television.NSSDCA, Ranger 9NASA, Ranger 9
The spent Saturn V third stage, crashed on purpose to ring the Moon for the seismometers.NSSDCA, Apollo 13 SIVB
NASA, 1970. crater left by its impactNSSDCA, Apollo 13 SIVBLROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
NASA, 1971. crater left by its impactNSSDCA, Apollo 14 SIVBLROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
NASA, 1972. crater left by its impactNSSDCA, Apollo 16 SIVBLROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
One of two craft that mapped the Moon's gravity, flown into a mountain at the end.NSSDCA, GRAIL-ANASA/JPL, NASA's GRAIL Lunar Impact Site Named for Astronaut Sally Ride
NASA, 2012. crater left by its impactNSSDCA, GRAIL-ALROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
The other of the two, moments later.NASA/JPL, NASA's GRAIL Lunar Impact Site Named for Astronaut Sally RideNSSDCA, GRAIL-A
Studied the Moon's thin air and dust, and was flown into its far side when it was done.NSSDCA, LADEESiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)
NASA, 2014. crater left by its impactNSSDCA, LADEELROC, Coordinates of Lunar Anthropogenic Features, 28 July 2016
Landed in Jezero crater, an ancient lake bed, to look for signs of past life and cache samples.NASA, Mars 2020 Perseverance
NASA/JPL-Caltech, 2021-02-18. active — driving; this is its LANDING siteNASA, Mars 2020 Perseverance
Landed in Gale crater and has been climbing Mount Sharp's layers since 2014.NASA, MSL CuriositySiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)
NASA/JPL-Caltech, 2012-08-06. active — driving on Mount Sharp; this is its LANDING siteNASA, MSL Curiosity
Listened to marsquakes and measured the planet's core.NASA/JPL, NASA Retires InSight Mars Lander MissionNASA/JPL, NASA's InSight Reveals the Deep Interior of Mars
NASA/JPL-Caltech, 2018-11-26. retired — mission ended December 2022 when its solar panels were too dustyNASA, InSightNASA/JPL, NASA Retires InSight Mars Lander Mission

Double stars19 traced

Sirius is two stars: the bright one and Sirius B, a white dwarf the size of the Earth.STScI/NASA Hubble release 2005-36, Sirius BBond et al. 2017, The Sirius System and its Astrophysical Puzzles
Sirius B, a white dwarf: 19.8 AU, 50.1 ySixth Catalog of Orbits of Visual Binary Stars (orbit table); worked out from its numbersBond et al. 2017, The Sirius System and its Astrophysical Puzzles
Procyon has a white dwarf companion too, Procyon B.Kaler, Stars: ProcyonSixth Catalog of Orbits of Visual Binary Stars (orbit table)
Procyon B, a white dwarf: 15 AU, 40.8 ySixth Catalog of Orbits of Visual Binary Stars (orbit table); worked out from its numbers
Alpha Centauri is three stars: A and B, close together, and little Proxima far out.Kervella et al. 2017, Proxima's orbit around Alpha Centauri
Alpha Centauri B, a K1 dwarf a little smaller than the Sun: 23.6 AU, 79.91 yPourbaix & Boffin 2016, Parallax and masses of alpha Centauri revisited; worked out from its numbersKervella et al. 2016, Close stellar conjunctions of alpha Centauri A and BKervella et al. 2017, Proxima's orbit around Alpha Centauri
Proxima Centauri, a red dwarf, the nearest star to the Sun: 8700 AU, 547000 yKervella et al. 2017, Proxima's orbit around Alpha CentauriESO release eso1629
Capella is two yellow giants circling each other every 104 days, closer together than the Earth is to the Sun.Torres et al. 2015, Capella revisited
Capella Ab, a yellow giant: 0.74 AU, 0.28473648186173856 yTorres et al. 2015, Capella revisited
Spica is two hot blue stars so close they pull each other out of round, circling every four days.Tkachenko et al. 2016, Stellar modelling of SpicaKaler, Stars: Spica
Spica B, a hot blue star: 0.13 AU, 0.010978781656399726 yTkachenko et al. 2016, Stellar modelling of Spica; worked out from its numbers
Algol 'winks' every 2.9 days, when its dimmer partner passes in front of it.Kaler, Stars: AlgolBaron et al. 2012, Imaging the Algol Triple System
Algol B, an orange subgiant: 0.062 AU, 0.007849418206707735 yBaron et al. 2012, Imaging the Algol Triple System; worked out from its numbers
Polaris has a close companion, Polaris Ab, measured by Hubble in 2005 and 2006.Evans et al. 2008, Direct Detection of the Close Companion of Polaris
Polaris Ab, a yellow-white dwarf star: 17 AU, 29.6 yEvans et al. 2008, Direct Detection of the Close Companion of Polaris; worked out from its numbers
Castor is six stars: three pairs, each pair a close binary.Kaler, Stars: CastorSixth Catalog of Orbits of Visual Binary Stars (orbit table)
Castor B, a white star (itself a pair): 104 AU, 459.1 ySixth Catalog of Orbits of Visual Binary Stars (orbit table)Kaler, Stars: CastorWashington Double Star Catalog, summary table
Mizar is a double you can split with a small telescope — and each of the two is itself a pair.Kaler, Stars: MizarMamajek et al. 2010, Discovery of a Faint Companion to Alcor
Mizar B, a white star (itself a pair): 360 AUWashington Double Star Catalog, summary table; worked out from its numbersMamajek et al. 2010, Discovery of a Faint Companion to AlcorKaler, Stars: Mizar

Stars whose distances disagree13 traced

Its distance is contested. This map uses Hipparcos's 1997 parallax, about 460 light-years; its 2007 re-reduction gives about 400, and Gaia about 580.Hipparcos 1997 (I/239), HIP 97278; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 97278Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 350 light-years; Gaia gives about 420.Hipparcos 1997 (I/239), HIP 89931; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 89931Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 210 light-years; Gaia gives about 240.Hipparcos 1997 (I/239), HIP 72105; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 72105Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 390 light-years; Gaia gives about 470.Hipparcos 1997 (I/239), HIP 1067; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 1067Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 360 light-years; Gaia gives about 460.Hipparcos 1997 (I/239), HIP 59747; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 59747Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 140 light-years; Gaia gives about 120.Hipparcos 1997 (I/239), HIP 4436; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 4436Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 840 light-years; Gaia gives about 990.Hipparcos 1997 (I/239), HIP 109492; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 109492Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 310 light-years; Gaia gives about 260.Hipparcos 1997 (I/239), HIP 68756; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 68756Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 330 light-years; Gaia gives about 380.Hipparcos 1997 (I/239), HIP 56211; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 56211Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 340 light-years; Gaia gives about 420.Hipparcos 1997 (I/239), HIP 83895; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 83895Gaia EDR3 source table, IRSA archive
Hipparcos and Gaia disagree on its distance: this map uses about 290 light-years; Gaia gives about 320.Hipparcos 1997 (I/239), HIP 40526; worked out from its numbersvan Leeuwen 2007 (I/311), HIP 40526Gaia EDR3 source table, IRSA archive
Its distance is contested. This map uses Hipparcos's 1997 parallax, about 430 light-years; Harper et al. (2017) give about 720, and Joyce et al. (2020), from its pulsations, about 550.Hipparcos 1997 (I/239), HIP 27989; worked out from its numbersHarper et al. 2017, An Updated 2017 Astrometric Solution for BetelgeuseJoyce et al. 2020, Standing on the shoulders of giants
Its distance is contested. This map uses Hipparcos's 2007 parallax, about 1,400 light-years; Schiller & Przybilla (2008) adopt about 2,600, assuming it belongs to the Cygnus OB7 association.van Leeuwen 2007 (I/311), HIP 102098; worked out from its numbersSchiller & Przybilla 2008, Quantitative spectroscopy of Deneb

Variable stars3 traced

two stars so close they are pulled out of shape, trading gas — its light rises and falls without pause every 12.9 daysKaler, Stars: SheliakZhao et al. 2008, First Resolved Images of Beta LyraeGCVS (B/gcvs), bet Lyr row, VizieR mirror
an eclipsing pair: every 2 days 21 hours its dim companion passes in front and it fades to a third of its light for about ten hoursGCVS (B/gcvs), bet Per row, VizieR mirror; worked out from its numbersKaler, Stars: Algol
good to about an hour: eclipses timed in 2012–2020 fit a longer period than those of 1783–1998, and published elements differ by more than that (times: Kreiner, Kraków)Kreiner, TIDAK (Kraków) up-to-date elements, EPHEM.TXT (PER BET row)Kraków O-C atlas, beta Per (Algol)Jetsu 2021, Say hello to Algol's new companion candidates (arXiv abstract)

Asteroids visited22 traced

The second-largest body in the asteroid belt, mapped by Dawn in 2011–12 — a protoplanet with a core, its south pole blasted out by the 500 km Rheasilvia basin.NASA, Dawn science: VestaSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)
Turns every 5.34 hours.JPL SBDB, 4 Vesta (rotation from Park et al. 2025)
A 34 km stony peanut that crosses Mars's orbit; NEAR Shoemaker orbited it for a year and landed on it in 2001.NASA, NEAR Shoemaker; worked out from its numbersNASA, Eros
Its shape is NEAR's laser altimeter map (16 million measurements, 0.125°); its face is P. Stooke's NEAR photomosaic.PDS, NEAR collected models, NLR Eros shape map labelPDS SBN, Stooke small bodies maps
Turns every 5.27 hours.JPL SBDB, 433 Eros
A spinning-top rubble pile half a kilometre across, reflecting about 4% of the light on it; OSIRIS-REx took a sample from it in 2020 and brought it home in 2023.NASA, Bennu factsNASA, OSIRIS-RExNASA, DidymosHergenrother et al. 2019, Nature Communications 10, 1291
Its shape is OSIRIS-REx's combined imaging and laser altimeter model (6.3 m); its face is the OCAMS global mosaic (Bennett et al. 2020).PDS, OSIRIS-REx altimetry SISPDS, OSIRIS-REx SPOv54 global models (g_06320mm)USGS Astrogeology, Bennu OCAMS Global PAN Mosaic 5cm (cites Bennett 2020)
Turns every 4.3 hours — and speeding up: sunlight's recoil (the YORP effect) shortens its day by about a second a century.NASA, Bennu facts; worked out from its numbersHergenrother et al. 2019, Nature Communications 10, 1291
On JPL's Sentry impact-risk list: about a 1 in 1,750 chance of hitting the Earth between 2178 and 2290 (as of 2026-10-29) — the second-highest score on the list, still well below concern (Palermo −1.40; Sentry gives it no Torino rating).JPL Sentry, 101955 BennuJPL Sentry, full list
A dark, spinning-top-shaped rubble pile 900 m across; Hayabusa2 sampled it twice in 2019 and brought 5.4 g home in 2020.JAXA, Hayabusa2JPL SBDB, 162173 Ryugu (from Watanabe 2019, Sugita 2019)Watanabe et al. 2019, Science (abstract)
Turns every 7.6 hours.JPL SBDB, 162173 Ryugu (from Watanabe 2019, Sugita 2019)
A 535 m sea-otter-shaped pile of rubble, probably two bodies stuck together; Hayabusa brought the first asteroid dust home from it in 2010.JPL SBDB, 25143 Itokawa (extent from, Science)NASA, ItokawaSiddiqi, Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016 (NASA)ESO, press release eso1405
Its shape is R. Gaskell's Hayabusa model (ICQ, 64 per face); no global map is used — it is drawn in its measured colour.PDS, Gaskell Itokawa shape model, q=64 ICQ label
Turns every 12.1 hours.JPL SBDB, 25143 Itokawa (extent from, Science)
A 761 m spinning top with a moon, Dimorphos — the pair DART struck in 2022 to test moving an asteroid. ESA's Hera reaches it in late 2026.Daly et al. 2023, Nature, Table 1NASA, DidymosESA, Hera
Its shape is DART's (SPC, 9.3 m); no global map exists — drawn in its measured colour.PDS SBN, DART Shapemodel Archive Bundle
Turns every 2.26 hours, about as fast as a rubble pile can without flying apart.NASA, DidymosESA, A hitchhiker's guide to Hera's target asteroids
Didymos's 150 m moon — the first world humans have moved: DART's impact on 26 September 2022 shortened its orbit by 33 minutes.Daly et al. 2023, Nature, Table 1Thomas et al. 2023, NatureNASA, Didymos
Its shape is DART's last approach images (SPC, 1.9 m) — of the half DART saw; the impact reshaped it, and Hera will measure what it looks like now. No global map exists — drawn in its measured colour.PDS SBN, DART Shapemodel Archive BundleDaly et al. 2023, Nature, Table 1NASA, Didymos
Goes round Didymos every 11 h 22 m, 1.15 km out. It kept one face towards it before DART; Hera will show whether it still does.Thomas et al. 2023, NatureESA, A hitchhiker's guide to Hera's target asteroidsJPL Horizons, Dimorphos (120065803)Agrusa et al. 2021, Icarus
Its shape is Dawn's elevation model (DLR, HAMO 48 pixels/degree); its face is Dawn's Framing Camera mosaic. The far north was in winter darkness while Dawn mapped it and is filled like the seen ground, not mapped.USGS Astrogeology, Vesta Dawn FC HAMO Global DTM 93mUSGS Astrogeology, Vesta Dawn FC HAMO Global Mosaic 60mNASA Photojournal PIA15795, A Part of Vesta's Shadowed Northern Hemisphere (2012)NASA Photojournal PIA15788, Vesta's Partly Shadowed Northern Regions (2012)
Its shape is Hayabusa2's (Watanabe et al. 2019, 49,152 facets); its face is the ONC v-band Basemap 2 (ISAS/JAXA, modified: re-centred, contrast stretched). That map's equirectangular projection distorts high latitudes, so beyond 60° it is filled like the seen ground, not mapped.ISAS/JAXA DARTS, Watanabe 2019 data (SHAPE_SFM_49k_v20180804.obj)ISAS/JAXA DARTS, Hayabusa2 map products, 02_ONC_v-band_Basemap2Watanabe et al. 2019, Science 364, 268JAXA JLPEDA, Hayabusa2 map products: equirectangular projection

Apophis1 traced

About 340 m across. Radar in March 2021 ruled out any impact for at least a century (NASA JPL); it is not on the impact-risk list.NASA/JPL, Earth Is Safe From Asteroid Apophis for 100-Plus YearsJPL Sentry, 99942 (removed 2021-02-21)JPL SBDB, 99942 Apophis (Brozovic et al. 2018)NASA, Apophis

Earth's companions10 traced

The first Earth trojan found: it leads Earth round the Sun, swinging back and forth about the L4 point 60° ahead of us.Connors, Wiegert & Veillet 2011, Nature 475, 481
Source: Connors, Wiegert & Veillet 2011, Nature 475, 481 — found in NASA WISE images.Connors, Wiegert & Veillet 2011, Nature 475, 481
Earth's second known trojan, also about the L4 point 60° ahead of us — and the bigger of the two.Santana-Ros et al. 2022, Nature Communications 13, 447
Source: Santana-Ros et al. 2022, Nature Communications 13, 447.Santana-Ros et al. 2022, Nature Communications 13, 447
Orbits the Sun, not Earth, but on a path so like ours that from Earth it seems to circle us once a year. Whether its rock is lunar is contested: a 2021 spectrum looked lunar (Sharkey et al.), but JWST in 2026 found it closer to enstatite-rich asteroid material.NASA/JPL news, Small Asteroid Is Earth's Constant CompanionSharkey et al. 2021, Communications Earth & Environment 2, 231Sharkey et al. 2021, the same paper free to read (arXiv)Sharkey et al. 2026, ApJ Letters 1010, L31 (JWST)Sharkey et al. 2026, the same paper free to read (arXiv)
Source: de la Fuente Marcos & de la Fuente Marcos 2016, MNRAS 462, 3441 (quasi-satellite); Sharkey et al. 2021, Communications Earth & Environment 2, 231 (spectrum).de la Fuente Marcos & de la Fuente Marcos 2016, MNRAS 462, 3441Sharkey et al. 2021, Communications Earth & Environment 2, 231
Source: Wiegert, Innanen & Mikkola 1997, Nature 387, 685.Wiegert, Innanen & Mikkola 1997, Nature 387, 685
Held by Earth's gravity for about two months in late 2024 without completing a full loop round us, then back to its own path round the Sun.de la Fuente Marcos & de la Fuente Marcos 2024, RNAAS 8, 224
Source: de la Fuente Marcos & de la Fuente Marcos 2024, RNAAS 8, 224.de la Fuente Marcos & de la Fuente Marcos 2024, RNAAS 8, 224
Not a moon of ours: seen turning with Earth, its path creeps round the Sun for centuries and then turns back — a horseshoe. Its steeply tilted orbit keeps it well away from us even when it passes.Wiegert, Innanen & Mikkola 1997, Nature 387, 685, An asteroidal companion to the Earth

Moons not placed11 traced

These are the moons found so far. Fainter ones are still being found, so this count will grow, and a new moon joins here once its orbit is measured.JPL SSD, planetary satellite discovery circumstances
136,500 km out, every 14.3 hours, in the Keeler GapJPL SSD, planetary satellite mean elements; worked out from its numbersNASA Science, Daphnis
JPL's day-by-day positions for it stop in January 2018, and it goes round about 600 times a year, so where it is today isn't known.JPL Horizons; worked out from its numbers
about 300 m tall and several times wider, about 117,000 km out, in the B ringNASA Photojournal PIA11665, A Small Find Near Equinox; worked out from its numbersNASA NSSDCA, Saturnian ring fact sheet
Cassini found it in July 2009, by a bright spot and its shadow. JPL publishes no orbit for it, so where it is now can't be said.NASA Photojournal PIA11665, A Small Find Near EquinoxJPL SSD, planetary satellite mean elements
about 10 km across, about 56,000 km out, nearly circularNASA Webb blog, 19 August 2025
Found by the James Webb Space Telescope in February 2025. As of November 2026, JPL has not published its orbital elements.NASA Webb blog, 19 August 2025JPL SSD, planetary satellite mean elements
about 22,250 km out, every 18 days (a preliminary fit)Bamberger 2025, A preliminary orbit for the satellite of Makemake
Its orbit is only preliminary, so neither its tilt nor its place today is known well enough to draw.Bamberger 2025, A preliminary orbit for the satellite of Makemake
about 24,000 km out, every 25 days, eccentricity about 0.3Kiss et al. 2019, Icarus (Table 2)Arakawa et al. 2021, AJ
JPL has no position for it, and its place today isn't known well enough to draw.JPL SSD, planetary satellite mean elementsJPL Horizons

Notes on the maps26 traced

Its size is measured, from the shadow it cast as it passed in front of a star. This artist's impression of its surface is based on: methane ice, like Pluto's, on a very bright surface. No craters or fine markings are drawn, because nothing says where they are.ESO release eso1142, ErisSicardy et al. 2011, NatureM. Brown, Caltech, Eris page
Its size is measured, from the shadow it cast as it passed in front of a star. This artist's impression of its surface is based on: methane and ethane ices on a reddish-brown surface. No craters or fine markings are drawn, because nothing says where they are.NASA Science, MakemakeESO eso1246, Ortiz et al. 2012: Makemake's occultation
Its size is measured, from the shadow it cast as it passed in front of a star. This artist's impression of its surface is based on: a surface rich in crystalline water ice. No craters or fine markings are drawn, because nothing says where they are.Trujillo et al., The Surface of 2003 EL61 in the Near InfraredOrtiz et al. 2017, NatureIAA-CSIC, Ortiz et al. 2017, Haumea's occultation (Nature 550, 219)
Its size is measured, from the shadow it cast as it passed in front of a star. This artist's impression of its surface is based on: its reddish colour. No craters or fine markings are drawn, because nothing says where they are.Emery et al. 2023, A Tale of 3 Dwarf Planets (JWST)Fornasier et al. 2013, TNOs are Cool VIIIBraga-Ribas et al. 2013, ApJ 773, 26: Quaoar's occultations (full text)
Its size is estimated from its heat glow, which depends on a model. This artist's impression of its surface is based on: one of the reddest colours beyond Neptune. No craters or fine markings are drawn, because nothing says where they are.Brown et al. 2011, surface composition of 2007 OR10Pál et al. 2016Kiss et al. 2019, Icarus: Gonggong's size from its heat
Its size is estimated from its heat glow, which depends on a model. This artist's impression of its surface is based on: its deep red colour. No craters or fine markings are drawn, because nothing says where they are.Emery et al. 2023, A Tale of 3 Dwarf Planets (JWST)Pál et al. 2012, Herschel: Sedna's diameter from its heat
Its size is measured from Voyager 2's images. This artist's impression of its surface is based on: one of the darkest surfaces known. No craters or fine markings are drawn, because nothing says where they are.NASA Science, ProteusJPL Solar System Dynamics, planetary satellite physical parameters (Archinal et al. 2018)
Akatsuki's composite reaches 61° north and 65° south; the poles beyond are shown with texture like the seen clouds, not mapped.ISAS/JAXA DARTS, Akatsuki UVI Longitude-Latitude Map Data v1.1
Galileo and Voyager mapped most of Europa; a small polar gap is shown with texture like the ground around it, not mapped.USGS Astrogeology, Europa Voyager-Galileo mosaic
Galileo and Voyager mapped most of Ganymede; small polar gaps are shown with texture like the ground around them, not mapped.USGS Astrogeology, Ganymede Voyager-Galileo mosaic
Galileo and Voyager mapped most of Callisto; small polar gaps are shown with texture like the ground around them, not mapped.USGS Astrogeology, Callisto Galileo-Voyager mosaic
Its colour here is Hubble's, measured in 2025… (hard-coded in WorldTransmission.mapNotes)STScI/MAST, OPAL
Cassini's own colour map of 11 August 2011… Great Storm of 2010–11… not beyond 79° north or 82° southNASA PDS Atmospheres Node, Cassini Jupiter and Saturn Global Map page
Akatsuki's ultraviolet view, 16–24 June 2016… unknown absorber… poles beyond 61° N and 65° S filled inISAS/JAXA DARTS, Akatsuki UVI Longitude-Latitude Map Data v1.1Zubko & Lee 2024, EPSC2024-284
Cassini's map of 11–12 December 2000…NASA Photojournal PIA07782
Its face here is New Horizons' (July 2015), sharp only on the side it flew past. The south, about a quarter of Pluto, has never been seen, most of it in polar night: it is drawn, with texture like the seen ground, not mapped. On the far side, about a third of Pluto, the light and dark areas are real, from distant photographs, and the fine detail on them is drawn.USGS Astrogeology, Pluto New Horizons global mosaic; worked out from its numbersJPL Horizons
Its face here is New Horizons' (July 2015), sharp only on the side it flew past. The south, about a quarter of Charon, has never been seen, most of it in darkness: it is drawn, with texture like the seen ground, not mapped. On the far side, about a third of Charon, the light and dark areas are real, from distant photographs, and the fine detail on them is drawn.USGS Astrogeology, Charon New Horizons global mosaic; worked out from its numbersJPL Horizons
Its face here is Voyager 2's (August 1989), the southern hemisphere in summer. The far north was in polar night, and with what the flyby missed, about a third of Triton has never been mapped; it is shown with texture like the seen ground, not mapped.USGS Astrogeology, Triton Voyager 2 mosaic; worked out from its numbersJPL Horizons
Its face here is Voyager 2's, January 1986 (USGS/Tammy Becker & JPL/Caltech) — the southern half only: the north was in polar night, and no spacecraft has been back. North of about the equator it is shown with texture like the seen ground, not mapped.NASA Science, Miranda; worked out from its numbersJPL Horizons
Its face here is Hayabusa2's (2018–19). The global map's projection distorts high latitudes, so beyond 60° it is shown with texture like the seen ground, not mapped.ISAS/JAXA, Hayabusa2JAXA JLPEDA, Hayabusa2 map products: equirectangular projection
Its face here is Cassini's, from its one close pass on 11 June 2004 (NASA/JPL/SSI/DLR). The far north and a few patches were never imaged; they are shown with texture like the seen ground, not mapped.NASA Science, Phoebe
Its size is estimated from its heat glow, which depends on a model. This artist's impression of its surface is based on: its neutral grey colour. No craters or fine markings are drawn, because nothing says where they are.Delsanti et al. 2010, A&A, A portrait of Plutino (90482) Orcus (arXiv)Brown et al. 2010, Orcus and Vanth (arXiv abstract)
Its size is measured from Voyager 2's images. This artist's impression of its surface is based on: its neutral colour. No craters or fine markings are drawn, because nothing says where they are.Grav, Holman & Fraser 2004, ApJ 613, L77, Photometry of irregular satellites of Uranus and Neptune (arXiv abstract)Terai & Itoh 2013, PASJ, Nereid photometry (arXiv abstract)JPL SSD, Planetary Satellite Physical Parameters (Nereid)
MESSENGER's colour mosaic stops a few degrees short of each pole (MESSENGER mapped them in black and white); those last few degrees are shown with texture like the ground around them, not mapped in colour.USGS Astrogeology, Mercury MESSENGER MDIS Basemap MD3 Color Global Mosaic 665mUSGS Astrogeology, Mercury MESSENGER MDIS Global Basemap BDR 166m
Dawn mapped almost all of Ceres; a small patch near the south pole that stayed in shadow is shown with texture like the ground around it, not mapped.NASA/JPL PIA20126, First Complete Look at Ceres' Poles (2015)USGS Astrogeology, Ceres Dawn FC Global Mosaic 400m
Its face here is Dawn's (2011–12). The far north was in winter darkness while Dawn mapped it; it is shown with texture like the seen ground, not mapped.USGS Astrogeology, Vesta Dawn FC HAMO Global Mosaic 60mNASA Photojournal PIA15795, A Part of Vesta's Shadowed Northern Hemisphere (2012)NASA Photojournal PIA15499, Northern Shadow (2012)

Local Group places19 traced

The most active star-forming region in the Local Group: a nebula lit by thousands of massive young stars.ESO release eso1117Chandra, 30 Doradus, 2012
The nearest supernova seen since the telescope was invented: its light reached Earth on 23 February 1987.ESO release eso0708ESA/Hubble heic0704NASA Webb release, February 2024
The star that exploded was a blue supergiant, Sanduleak −69° 202.ESO release eso0708SIMBAD, SN 1987A
Neutrinos from its collapse were caught on Earth hours before the light — the first detected from an exploding star (Kamiokande-II and IMB).ESO release eso0708Nobel Prize in Physics 2002, popular information
Webb found emission lines that point to a neutron star in the debris (Fransson et al. 2024, Science 383, 898).NASA Webb release, February 2024Fransson et al. 2024, Science 383, 898Fransson et al. 2024, the same paper free to read (arXiv)
The LMC's second-largest star-forming region after the Tarantula: bubbles of gas blown by generations of young stars.ESA/Hubble heic1011
Henize N11 in the LMC's H-alpha survey.ESA/Hubble heic1011
A superbubble about 325 by 250 light-years, cleared out by a cluster of massive stars, probably with help from their supernovae.NOIRLab, Superbubble Complex N44
Henize N44.SIMBAD, LHA 120-N 44ESO Picture of the Week potw1236a: the N44 catalogue "compiled and published in 1956 by American astronomer–astronaut Karl Henize"
The brightest supernova remnant in the LMC in X-rays, rich in oxygen thrown out by a massive star.Chandra, N132D
A supernova remnant with a magnetar, SGR 0526−66, within its outline, though whether the two are truly linked is debated. Its giant flare came on 5 March 1979.Park et al. 2012, ApJ 748, 117Mereghetti 2008 (giant flare table)
The SMC's most active star-forming region, where stars are still forming from gas much poorer in metals than the Milky Way's.Cignoni et al. 2011, AJ 141, 31; worked out from its numbersCignoni et al. 2011, the same paper free to read (arXiv)ESA/Webb weic2301
Henize N66A.SIMBAD, NGC 346
A young cluster at the edge of the SMC's Wing, carving a cavity in the gas round it.ESA/Hubble heic0702
A star-forming region in M33, some 1,300 light-years across, lit by more than 200 of the hottest, most massive kinds of stars.NASA Webb release, NGC 604, March 2024ESA/Hubble opo9627a
One of M33's most luminous H II regions, a nursery of massive stars.Relaño & Kennicutt 2009; worked out from its numbers
Water masers here and across the disc were tracked by radio telescopes until M33's spin across the sky could be seen — a geometric distance.Brunthaler et al. 2005
730 ± 168 kpc from the masers' motion (Brunthaler et al. 2005, Science 307, 1440).Brunthaler et al. 2005
NGC 2070 in the New General Catalogue; Henize N157 in the LMC's H-alpha survey.Doran et al. 2013, A&A 558, A134 (arXiv:1308.3412), VLT-FLAMES Tarantula Survey XIHenize 1956, ApJS 2, 315, Catalogues of Hα-emission stars and nebulae in the Magellanic CloudsESO, The Tarantula Nebula

Andromeda's places8 traced

Andromeda's heart looks double: two peaks of starlight, P1 and P2, 0.49 arcseconds apart — about 1.8 parsecs (Lauer et al. 1993).Bender et al. 2005Tremaine 1995
They are one thing: a disc of stars on lopsided, aligned orbits round the central black hole, crowding where they move slowest (Tremaine 1995's eccentric disc; Bender et al. 2005).Tremaine 1995Bender et al. 2005
Inside P2 is P3, a tiny cluster of young blue stars — probably born in a burst about 200 million years ago (Bender et al. 2005).Bender et al. 2005
P3's stars circle the black hole at about 1,700 km/s, 0.19 parsecs out, which weighs it at about 140 million Suns (Bender et al. 2005).Bender et al. 2005
In 1999 the POINT-AGAPE survey saw a star in Andromeda brighten and fade over months as something passed in front of it and bent its light — and the light curve has a small extra wiggle.An et al. 2004Paulin-Henriksson et al. 2003
PA-99-N2b is a candidate, not a confirmed planet: a single microlensing event in 1999, which can never be watched again.An et al. 2004Ingrosso et al. 2009
A binary lens whose companion has about a hundredth of the primary's mass fits the wiggle (An et al. 2004).An et al. 2004
If the lens is an ordinary half-solar-mass star in the disc, the companion is about 6 times Jupiter's mass — a planet (Ingrosso et al. 2009). If the lens is heavier, it could be a brown dwarf or a small star (An et al. 2004).Ingrosso et al. 2009An et al. 2004

Local Group tour11 traced

The Milky Way's biggest satellite, about 162,000 light-years away, its disc tipped about 35° to us with the north-east side nearest.Pietrzyński et al. 2019; worked out from its numbersvan der Marel & Cioni 2001Erkal et al. 2019
The largest and brightest star-forming region in the Local Group, home to the most massive stars known.ESA/Webb weic2212, Tarantula NebulaKalari et al. 2022
In 1987 a star here exploded — the nearest supernova seen in modern times, its neutrinos caught on Earth.Chandra X-ray Center, SN 1987A (2017)ESO eso0708, SN 1987A
Not a flat disc but a cigar of stars pointing nearly at us, its eastern side up to about 65,000 light-years nearer than its western.Scowcroft et al. 2016; worked out from its numbersRipepi et al. 2017
The SMC's brightest nursery, making stars from gas with a fifth of the Sun's metals — as the early universe did.Valerdi et al. 2019; worked out from its numbersNASA Webb, planet-forming disks in NGC 346ESA/Webb weic2301, NGC 346
A lone dwarf irregular galaxy about 1.5 million light-years away, in the Local Group and not clearly a satellite of either giant.McConnachie 2012; worked out from its numbers
A dwarf galaxy far out at the Local Group's edge, isolated from both giants.Leaman et al. 2012McConnachie 2012
One of the faintest galaxies known that still holds gas and has made stars recently.Irwin et al. 2007
The Local Group's third spiral, probably bound to Andromeda, its disc tilted 52° to us.Kam et al. 2017McConnachie 2012
In Triangulum, a nebula about 1,300 light-years across lit by more than 200 massive stars.NASA Webb, NGC 604
Its dense nucleus holds no black hole heavier than about 1,500 to 3,000 Suns.Gebhardt et al. 2001Merritt, Ferrarese & Joseph 2001

Andromeda tour6 traced

At the centre, two peaks of starlight 1.8 parsecs apart are one lopsided disc of stars circling a black hole of about 140 million Suns.Bender et al. 2005Tremaine 1995
Much of Andromeda's star formation and dust lies in a ring about 10 kpc out, which may have been set rippling when M32 plunged through the disc.Gordon et al. 2006Block et al. 2006
G1 is the brightest of Andromeda's confirmed globular clusters in the Revised Bologna Catalogue (V = 13.8), about 35 kpc from the centre in projection.Revised Bologna Catalogue v5, VizieR V/143 (Galleti et al.)
A tidal stream of stars runs south-east from Andromeda, its far end about 100 kpc behind it.McConnachie et al. 2003
Here, in 1999, a microlensing event hinted at a planet of about 6 Jupiter masses — still only a candidate, and it can never be checked again.Ingrosso et al. 2009An et al. 2004
Andromeda XIX is the most spread-out of Andromeda's dwarf galaxies: half its light lies within about 3 kpc of its centre.Martin et al. 2016

Milky Way tour21 traced

The Milky Way from outside: a barred spiral about 100,000 light-years across, with the Sun some 27,000 light-years from its centre.NASA Imagine the Universe, the Milky Way; worked out from its numbersGRAVITY Collaboration 2022
The Orion Nebula, about 1,300 light-years away, is the nearest large nursery of massive stars.NASA Hubble, Messier 42; worked out from its numbersMenten et al. 2007
W51 is one of the Milky Way's biggest star-forming complexes; a maser's parallax puts it about 17,600 light-years away.Bik et al. 2019; worked out from its numbersSato et al. 2010
PSR B0329+54, the brightest radio pulsar in the PSRπ survey, had its distance measured directly by parallax with the VLBA: about 5,500 light-years.Deller et al. 2019; worked out from its numbers
The Carina Nebula, about 7,500 light-years away, holds a dozen or more stars of at least 50 to 100 times the Sun's mass.ESA/Hubble heic0707, Carina NebulaNASA Hubble, Caldwell 92
SGR 1806−20, a magnetar some 28,000 to 49,000 light-years away, let off a giant flare on 27 December 2004 that briefly lit up Earth's upper atmosphere.NASA, Swift and the 27 December 2004 flareCrowther et al. 2011Svirski et al. 2011
Sagittarius B2, near the Galactic Centre, is one of the most massive clouds of star-forming gas in the Galaxy.Pols et al. 2018Ginsburg et al. 2018
Sagittarius A*: a black hole of 4.3 million Suns, about 27,000 light-years away, weighed by the stars that orbit it.GRAVITY Collaboration 2022; worked out from its numbers
S2 goes round the black hole every 16 years; in May 2018 it passed within about 120 AU of it at some 7,700 km/s.GRAVITY Collaboration 2018Gillessen et al. 2017
S29 plunged to about 100 AU from the black hole in 2021 on an orbit almost as stretched as an orbit can be (eccentricity 0.97).GRAVITY Collaboration 2022
S55 is the quickest of the stars here, going round in about 12 to 13 years.Gillessen et al. 2017; worked out from its numbersGRAVITY Collaboration 2022
A magnetar, SGR J1745−2900, spins once every 3.8 seconds only about 2.4 arcseconds from the black hole on the sky.Rea et al. 2013
Omega Centauri, the Milky Way's biggest globular cluster, may be the core of a dwarf galaxy the Milky Way swallowed.NASA Hubble, Caldwell 80
Fimbulthul is a stream of stars pulled out of Omega Centauri by the Milky Way's tide.Ibata et al. 2019
GD-1 is a thread of old stars about 23,000 to 32,000 light-years away — the remains of a star cluster torn apart long ago.Koposov et al. 2010
Palomar 5 is a globular cluster coming apart now: its stars trail out ahead of it and behind it in two long tails.Odenkirchen et al. 2001
The Sagittarius dwarf galaxy, about 86,000 light-years away on the far side of the centre, is being torn apart as it falls through the Milky Way.McConnachie 2012; worked out from its numbersVasiliev et al. 2021Kunder & Chaboyer 2009
Segue 1, about 75,000 light-years away, is a whole galaxy that shines with only about 300 Suns' worth of light.Simon et al. 2011; worked out from its numbers
The Large Magellanic Cloud, about 162,000 light-years away, is the biggest of the Milky Way's satellite galaxies.Pietrzyński et al. 2019Erkal et al. 2019
Antlia II spreads its stars about as wide as the Large Magellanic Cloud, yet shines roughly 2,000 to 4,000 times fainter.Torrealba et al. 2019; worked out from its numbersJi et al. 2021McConnachie 2012
Leo I, about 840,000 light-years out, is among the most distant of the Milky Way's companions.McConnachie 2012; worked out from its numbersSohn et al. 2013

Tours4 traced

A selection of stars and brown dwarfs within about 40 light-years of home.NASA Webb, temperature of a rocky exoplanet (TRAPPIST-1 b)
From Voyager 1 to a black hole 55 million light-years away.ESO eso1907, first black hole image
Stars we know have planets — some of them rocky, some in their star's warm zone.NASA Webb, temperature of a rocky exoplanet (TRAPPIST-1 b)Gilbert et al. 2020, TOI-700
White dwarfs, neutron stars and black holes — what stars leave behind.NASA Science, Stars

The farthest things30 traced

A patch of sky a tenth the width of the full Moon, stared at for a million seconds: about 10,000 galaxies.ESA/Hubble heic0406, Hubble Ultra Deep FieldBeckwith et al. 2006
Field centre and the count of objects: Beckwith et al. 2006, AJ 132, 1729.Beckwith et al. 2006
The Webb telescope's JADES survey went deeper here; JADES-GS-z14-0, a galaxy seen 290 million years after the Big Bang, lies nearby in the same deep-survey region (GOODS-South), about 6′ from this field's centre: the line runs out to its distance, not to it.Eisenstein et al. 2023, JADES overview; worked out from its numbersCarniani et al. 2024Planck Collaboration, cosmological parameters (2018)
Its card opens at redshift 1 (about 11 billion light-years) — a point on the beam, not one galaxy.Planck Collaboration, cosmological parameters (2018); worked out from its numbers
The first deep image from the Webb telescope (July 2022): a galaxy cluster whose gravity magnifies thousands of galaxies far behind it.ESA/Webb weic2209, Webb's First Deep Field
Image centre and the cluster's light-travel time (4.6 billion years): ESA/Webb, Webb's First Deep Field (weic2209a). Its card sits at the cluster.ESA/Webb image weic2209aESA/Webb release weic2209
A galaxy seen as it was about 280 million years after the Big Bang, confirmed by the Webb telescope's spectrograph in 2025.Naidu et al. 2025, arXiv:2505.11263
Naidu et al. 2025, arXiv:2505.11263 — redshift 14.44 ± 0.02 (JWST NIRSpec), position from its Table 1.Naidu et al. 2025, arXiv:2505.11263
The farthest galaxy known when found in 2024 — and in it, oxygen: stars had already lived and died there.ESO release eso2507
Carniani et al. 2024, Nature — found at redshift 14.32 with JWST NIRSpec; position from its Table 1.Carniani et al. 2024, Nature 633, 318Carniani et al. 2024, the same paper free to read (arXiv)
ALMA then caught its oxygen line: redshift 14.1793 ± 0.0007 (Schouws et al. 2025, ApJ), 14.1796 (Carniani et al., arXiv:2409.20533). Placed at the ALMA value.Schouws et al. 2025, ApJ 988, 19Carniani et al., arXiv:2409.20533
The farthest galaxy known before the Webb telescope — Hubble found it in 2016; Webb's spectra suggest a black hole feeding at its heart.Bunker et al. 2023, A&A 677, A88Bunker et al. 2023, the same paper free to read (arXiv)Oesch et al. 2016, ApJ 819, 129Oesch et al. 2016, the same paper free to read (arXiv)Maiolino et al. 2024, Nature 627, 59
Position: Oesch et al. 2016, ApJ 819, 129 (Table 2).Oesch et al. 2016, ApJ 819, 129Oesch et al. 2016, the same paper free to read (arXiv)
Redshift 10.6034 ± 0.0013: Bunker et al. 2023, A&A 677, A88 (JWST NIRSpec).Bunker et al. 2023, A&A 677, A88Bunker et al. 2023, the same paper free to read (arXiv)
The black hole: Maiolino et al. 2024, Nature — evidence, not yet settled.Maiolino et al. 2024, Nature 627, 59Bunker et al. 2023, A&A 677, A88Bunker et al. 2023, the same paper free to read (arXiv)
Probably a massive star collapsing to a black hole, its flash of gamma rays caught by NASA's Swift on 23 April 2009 — about 13 billion years after it happened.Tanvir et al. 2009, Nature 461, 1254NASA Swift, GRB 090423 release
Redshift 8.26 (−0.08/+0.07): Tanvir et al. 2009, Nature 461, 1254.Tanvir et al. 2009, Nature 461, 1254
Position: Swift XRT, UVOT-enhanced (Evans et al., GCN Circular 9205; ±1.7″).Evans et al., GCN Circular 9205
The closest of these flares known when it was found in 2019. A star about the Sun's mass met a black hole of about a million Suns.Nicholl et al. 2020, MNRAS 499, 482Nicholl et al. 2020, the same paper free to read (arXiv)
Nicholl et al. 2020, MNRAS 499, 482: position, redshift 0.01513, 65.6 Mpc, the masses.Nicholl et al. 2020, MNRAS 499, 482Nicholl et al. 2020, the same paper free to read (arXiv)
The tide takes such a star about 0.47 au from the hole, outside its 0.02 au horizon: worked out from those masses.Nicholl et al. 2020, MNRAS 499, 482; worked out from its numbersNicholl et al. 2020, the same paper free to read (arXiv)
A star torn apart at the centre of the galaxy PGC 043234, found in 2014 by a network of small telescopes.Holoien et al. 2016, MNRAS 455, 2918Holoien et al. 2016, the same paper free to read (arXiv)ASAS-SN project page, Ohio State
Holoien et al. 2016, MNRAS 455, 2918: position, redshift 0.0206, 90.3 Mpc.Holoien et al. 2016, MNRAS 455, 2918Holoien et al. 2016, the same paper free to read (arXiv)
In March 2011 a gamma-ray alarm that would not stop: a jet from a small galaxy's centre, pointed almost at us, peaking at about 100 times the brightest active galaxies.Levan et al. 2011, Science 333, 199Levan et al. 2011, the same paper free to read (arXiv)Andreoni et al. 2022, Nature 612, 430Andreoni et al. 2022, the same paper free to read (arXiv)
Levan et al. 2011, Science 333, 199: position, redshift 0.3534 ± 0.0002, its peak.Levan et al. 2011, Science 333, 199Levan et al. 2011, the same paper free to read (arXiv)
The most distant one with a jet known when found in 2022, and so bright because that jet points nearly at us.ESO release eso2216Andreoni et al. 2022, Nature 612, 430Andreoni et al. 2022, the same paper free to read (arXiv)
Andreoni et al. 2022, Nature 612, 430: position from its radio data, redshift 1.19325 ± 0.00024.Andreoni et al. 2022, Nature 612, 430Andreoni et al. 2022, the same paper free to read (arXiv)
A star torn apart in 2019. That October the IceCube detector caught a high-energy neutrino from its direction, about a 0.2% chance by coincidence.Stein et al. 2021, Nature Astronomy 5, 510Transient Name Server, AT 2019dsg
A star torn apart at the centre of a quiet galaxy in 2018. About 750 days later it began throwing out a fast outflow, seen in radio.Short et al. 2020, MNRASCendes et al. 2022, ApJTransient Name Server, AT 2018hyz
The first of these flares seen by the TESS satellite, whose half-hourly pictures caught it brightening about eight days before it was discovered in January 2019.Holoien et al. 2019, ApJ 883, 111Transient Name Server, AT 2019ahk

Superclusters23 traced

Where drawn: Perseus Cluster (Abell 426) as the anchor (NED); the supercluster is an elongated chain, not a sphereNASA/IPAC Extragalactic Database, Abell 426Joeveer, Einasto & Tago 1978, MNRAS 185, 357
Haynes, M. P. & Giovanelli, R. 1986, ApJL 306, L55Haynes & Giovanelli 1986, ApJ 306, L55
Joeveer, M., Einasto, J. & Tago, E. 1978, MNRAS 185, 357Joeveer, Einasto & Tago 1978, MNRAS 185, 357
Where drawn: Coma Cluster (Abell 1656) as the anchor (NED); the other main member is the Leo Cluster Abell 1367 (RA 176.1561, Dec 19.7625, z 0.0219, NED)NASA/IPAC Extragalactic Database, Abell 1656NASA/IPAC Extragalactic Database, Abell 1367Gregory & Thompson 1978, ApJ 222, 784
Gregory, S. A. & Thompson, L. A. 1978, ApJ 222, 784Gregory & Thompson 1978, ApJ 222, 784
Where drawn: APPROXIMATE: midpoint of the RA 9h-14h span in the SDSS equatorial slice (Dec ~0), as described by Gott et al. 2005; not a published centroidGott et al. 2005, ApJ 624, 463; worked out from its numbers
Gott, J. R. III et al. 2005, ApJ 624, 463 (doi:10.1086/428890)Gott et al. 2005, ApJ 624, 463Gott et al. 2005, the same paper free to read (arXiv)
Einasto, M. et al. 2011, ApJ 736, 51 (morphology; richest members SCl 126 and SCl 111)Einasto et al. 2011, ApJ 736, 51Einasto et al. 2011, The same paper on arXiv
Where drawn: APPROXIMATE: RA 14h50m, Dec +46 deg as commonly quoted (original surveys used B1950 coordinates); z = cz/c for the ~15,000 km/s centre of the velocity gapKirshner et al. 1987, ApJ 314, 493; worked out from its numbersKirshner et al. 1981, ApJ 248, L57
Kirshner, R. P., Oemler, A., Schechter, P. L. & Shectman, S. A. 1981, ApJL 248, L57Kirshner et al. 1981, ApJ 248, L57
Kirshner, R. P. et al. 1987, ApJ 314, 493Kirshner et al. 1987, ApJ 314, 493
Where drawn: deepest density minimum ("Lacerta-2.4") at supergalactic [+1650, -700, +1650] km/s = [+22, -9, +22] Mpc (Tully et al. 2019, Table 1), converted here to RA/DecTully et al. 2019, ApJ 880, 24; worked out from its numbersTully et al. 2019, The same paper on arXiv
Tully, R. B. et al. 2008, ApJ 676, 184Tully et al. 2008, ApJ 676, 184Tully et al. 2008, The same paper on arXiv (Astrophys.J.676:184-205,2008)
Tully, R. B. et al. 2019, ApJ 880, 24 (doi:10.3847/1538-4357/ab2597)Tully et al. 2019, ApJ 880, 24Tully et al. 2019, the same paper free to read (arXiv)
Tully, R. B. & Fisher, J. R. 1987, Nearby Galaxies AtlasTully et al. 2019, text and reference list
About 522 million ly across. Where drawn: centroid of the attractor region at supergalactic [-4700, +1300, -500] km/s (Tully et al. 2014, Methods), converted here to RA/DecTully et al. 2014, Nature 513, 71; worked out from its numbersTully et al. 2014, the same paper free to read (arXiv)
distance from velocities with authors' H0Tully et al. 2014, Nature 513, 71; worked out from its numbersTully et al. 2014, the same paper free to read (arXiv)
Tully, R. B., Courtois, H., Hoffman, Y. & Pomarede, D. 2014, Nature 513, 71 (doi:10.1038/nature13674)Tully et al. 2014, Nature 513, 71Tully et al. 2014, the same paper free to read (arXiv)
Where drawn: core cluster Abell 3558 (NED, z from 2018MNRAS.481.1055H)NED, Abell 3558Proust et al. 2006, arXiv:astro-ph/0509903Haines et al. 2018, MNRAS 481, 1055
Raychaudhury, S. 1989, Nature 342, 251Proust et al. 2006, arXiv:astro-ph/0509903
Where drawn: Hercules Cluster Abell 2151 as the anchor (NED); members include Abell 2147 (z 0.0366) and Abell 2152 (z 0.0442), both NEDNED, ABELL 2151NED, ABELL 2147NED, ABELL 2152Einasto et al. 2001, AJ 122, 2222 (arXiv:astro-ph/0012536), Table A1
Einasto, M. et al. 2001, AJ 122, 2222 (supercluster catalogue)Einasto, Einasto, Tago, Müller & Andernach 2001, AJ 122, 2222 (arXiv:astro-ph/0012536)Einasto et al. 2001, AJ 122, 2222
Shapley, H. 1930, Harvard Obs. Bull. 874, 9 (first noted)Biviano 2000, From Messier to Abell: 200 years of science with galaxy clusters (arXiv:astro-ph/0010409)

Gravitational waves8 traced

first direct detection of gravitational wavesAbbott et al. 2016, GW150914
first three-detector BBHAbbott et al. 2019, GWTC-1, PRX 9, 031040Abbott et al. 2017, GW170814
binary neutron star with kilonova + GRB 170817A (multi-messenger)Abbott et al. 2017, Multi-messenger Observations of a Binary Neutron Star Merger
best-localised O2 BBHAbbott et al. 2019, GWTC-1, PRX 9, 031040
first clearly unequal-mass BBHAbbott et al. 2020, GW190412
23 Msun + 2.6 Msun mystery objectAbbott et al. 2020, GW190814
loud O3b BBHHannam et al. 2022, General-relativistic precession in a black-hole binary
loudest signal when reported in 2025 (SNR ~80); area-theorem testLVK 2025, GW250114: Testing Hawking's Area Law

The cosmic clock17 traced

The peak of star formation: about 3.5 billion years after the Big BangMadau & Dickinson 2014, ARA&A; worked out from its numbers
Reionization: starlight clears the fog between galaxiesRobertson 2022, Galaxy Formation and Reionization
The farthest galaxy measured: MoM-z14, 280 million years inNaidu et al. 2025, MoM-z14
The Dark Ages: no stars yetRobertson 2022, Galaxy Formation and Reionization
The oldest light: about 370,000 years after the Big BangRobertson 2022, Galaxy Formation and Reionization; worked out from its numbers
As far as we can see, not where the universe ends. Farther out is further back in time.Davis & Lineweaver 2004, Expanding ConfusionESA, Planck and the cosmic microwave background
Light still outweighs matter: the universe is a hot, glowing fog.Frieman, Turner & Huterer 2008, Dark Energy and the Accelerating Universe; worked out from its numbersESA, Planck and the cosmic microwave background
Matter now outweighs light, and gravity can begin to gather it.Frieman, Turner & Huterer 2008, Dark Energy and the Accelerating Universe; worked out from its numbers
The first atoms form, the fog clears, and the light we see as the cosmic microwave background sets off.ESA, Planck and the cosmic microwave background
The dark ages: the fog has gone, and no star we have yet seen is shining.Robertson 2022, Galaxy Formation and ReionizationNaidu et al. 2025, MoM-z14
Galaxies are shining. The farthest seen so far, MoM-z14, is from about now.Naidu et al. 2025, MoM-z14
Galaxies are growing and merging, and making the heavy elements that later planets need.Madau & Dickinson 2014, ARA&A
Dark energy starts to win: the expansion stops slowing and begins to speed up.Frieman, Turner & Huterer 2008, Dark Energy and the Accelerating Universe; worked out from its numbers
The Sun and its planets form, about 4.57 billion years ago.Connelly et al. 2012, Science, abstract
Dark energy now outweighs all the matter.Frieman, Turner & Huterer 2008, Dark Energy and the Accelerating Universe; worked out from its numbers
The model's forecast, not an observation: galaxies beyond our own group drift out of sight as space speeds up.Krauss & Scherrer 2007, The Return of a Static Universe
A diagram, cut through home: nothing can stand outside it. Real: 43,000 galaxies, 50,000 quasars. The faint web and the scattered galaxies are drawn at the measured scale. Oldest light: NASA/WMAP, in the colour it left with, its mottling exaggerated thousands of times.NASA LAMBDA, WMAP DR5 data product images (nine-year ILC map)NASA Science, WMAP OverviewNASA GSFC, John Mather: COBE Science Results

Mission replays35 traced

Four giant planets in twelve years, on a line-up that comes round about once in 175 years.NASA, Voyager fact sheet; worked out from its numbers
1977-08-23: Three days out from its 20 August 1977 launch, sixteen days before Voyager 1, on a slower path.NASA, Voyager 2 mission page; worked out from its numbersNASA, Voyager 1 mission pageNASA, Voyager fact sheet
1979-07-09: Jupiter. Its gravity takes it from too slow to leave the Sun to fast enough.NASA, Basics of Space Flight, ch. 4, with its Voyager 2 velocity figureNASA, Voyager 2 mission page
1981-08-26: Saturn, and the aim for Uranus: only possible because Voyager 1 had already seen Titan.NASA, Voyager frequently asked questionsNASA, Voyager fact sheetNSSDCA Master Catalog, Voyager 2
1986-01-24: Uranus. Still the only visit, and its rings and moons are seen up close.NASA, Voyager 2 mission page
1989-08-25: Neptune and Triton, still the only visit. The pass bends the craft south, out of the planets' plane.NASA, Voyager 2 mission pageNASA, Voyager fact sheet
The faster of the twins, which gave up every other planet for one close look at Titan.NASA, Voyager frequently asked questionsNASA, Voyager 1 mission page
1977-09-08: Three days out from its 5 September 1977 launch, after Voyager 2, on a faster path that soon overtakes it.NASA, Voyager 1 mission pageNASA, Voyager fact sheet
1979-03-05: Jupiter. It finds active volcanoes on Io, the first seen beyond Earth.NASA, Voyager fact sheetNASA, IoNASA, Voyager 1 mission page
1980-11-12: Saturn and Titan. That pass throws the craft north out of the planets' plane, so it never goes on to Uranus or Neptune.NASA, Voyager fact sheetNASA, Voyager 1 mission page
Too heavy to go direct: it swung past Venus twice, Earth and Jupiter to get there.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004
1997-10-16: Launched on 15 October 1997, and sent inwards, away from Saturn.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004NASA, Cassini mission page
1998-04-26: Venus, the first swing.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004
1999-06-24: Venus again.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004
1999-08-18: Earth, 55 days later, and now it can reach the outer planets.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004; worked out from its numbers
2000-12-30: Jupiter, the last push.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004
2004-07-01: Saturn. It fires its engine and is caught: thirteen years in orbit begin.NASA/JPL, Cassini-Huygens Saturn Arrival press kit, June 2004NASA, Cassini mission page
The fastest launch of any craft, and nine and a half years to the first look at Pluto.NASA, New Horizons mission page; worked out from its numbersStern 2008, Space Sci. Rev., New Horizons overview
2006-01-20: Launched on 19 January 2006, and past the Moon's orbit in about nine hours.NSSDCA, New HorizonsStern 2008, Space Sci. Rev., New Horizons overviewNASA, Astronomy Picture of the Day 2006 January 24: New Horizons "passed the Moon only nine hours after launch"
2007-02-28: Jupiter, a year later, which cuts three years from the trip.NASA, New Horizons mission pageNSSDCA, New Horizons
2015-07-14: Pluto, and the first close look at it: mountains of ice and a heart-shaped plain.NSSDCA, New HorizonsNASA, Pluto factsNASA, New Horizons mission page
Launched too slowly to reach Jupiter, on purpose: it came back past Earth two years later for the rest.NASA, Juno mission pageNSSDCA, Juno
2011-08-06: Launched on 5 August 2011, into a loop that takes it back towards Earth.NSSDCA, JunoNASA, Juno mission page
2013-10-09: Earth, and the speed it needed all along.NSSDCA, JunoNASA, Juno mission page
2016-07-05: Jupiter. It fires its engine and is caught, in the first polar orbit round the planet.NSSDCA, JunoNASA, Juno mission page
Before Jupiter it was too slow to ever leave the Sun: 13.7 km/s, with 19.1 needed there. Jupiter's pull changed that.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Jupiter, 5 March 1979: 13.7 → 23.3 km/s against the Sun.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Saturn, 12 November 1980: 20.3 → 21.4 km/s against the Sun.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Speeds from its trajectory, about two to three months each side of the pass (JPL Horizons).JPL Horizons vectors, read 2026-11-01
Before Jupiter it was too slow to ever leave the Sun: 10.5 km/s, with 18.8 needed there. Jupiter took it just past the line.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Jupiter, 9 July 1979: 10.5 → 19.5 km/s against the Sun.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Saturn, 26 August 1981: 15.8 → 20.3 km/s against the Sun.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Uranus, 24 January 1986: 18.0 → 19.7 km/s against the Sun.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Neptune, 25 August 1989: 18.9 → 16.7 km/s against the Sun.JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, Voyager planetary closest approaches
Neptune slowed it: the close pass over the planet's north pole bent its path south, out of the planets' plane. It no longer needed the speed.NASA, Neptune exploration; worked out from its numbersJPL, Voyager 2 mission pageJPL Horizons vectors, read 2026-11-01

The heliosphere4 traced

Heliopause: Voyager 1 at about 122 AU (2012), Voyager 2 at 119 AU (2018)NASA Science, Voyager Interstellar MissionRichardson et al. 2019, Nature Astronomy, Voyager 2 plasma observations
Oort cloud inner edge, 2,000 to 5,000 AUNASA Science, Oort Cloud facts
Oort cloud outer edgeNASA Science, Oort Cloud facts
Termination shock: Voyager 1 at 94 AU (2004), Voyager 2 at 84 AU (2007)Stone et al. 2005, Science 309, 2017Stone et al. 2008, Nature 454, 71JPL, Voyager 2 proves Solar System is squashed

Star streams19 traced

A river of stars — what is left of a cluster or small galaxy the Milky Way pulled apart.Bonaca & Price-Whelan 2024, Stellar Streams in the Gaia Era
A river of stars torn from the globular cluster Eridanus by the Milky Way's tide.Myeong et al. 2017, ApJL, tidal tails around Eridanus and Palomar 15Mateu 2023, galstreams, MNRAS
A river of stars torn from M2 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field IMateu 2023, galstreams, MNRAS
A river of stars torn from M30 by the Milky Way's tide.Sollima 2020, The eye of Gaia on globular clusters structure: tidal tailsMateu 2023, galstreams, MNRASNASA, Hubble Messier catalog: "M30, also called NGC 7099"
A river of stars torn from M5 by the Milky Way's tide.Grillmair 2019, ApJ, 50 degree trailing tidal tail of M5Ibata et al. 2021, Charting the Galactic acceleration field I
A river of stars torn from M68 by the Milky Way's tide.Palau & Miralda-Escude 2019, tidal stream of M68Ibata et al. 2021, Charting the Galactic acceleration field IMateu 2023, galstreams, MNRAS
A river of stars torn from M92 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field IMateu 2023, galstreams, MNRAS
A river of stars torn from NGC 1261 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field I
A river of stars torn from NGC 1851 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field I
A river of stars torn from NGC 288 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field ISollima 2020, The eye of Gaia on globular clusters structure: tidal tails
A river of stars torn from NGC 3201 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field IMateu 2023, galstreams, MNRAS
A river of stars torn from NGC 5053 by the Milky Way's tide.Ye et al. 2026, ApJL, Long Tidal Tails of NGC 5024
A river of stars torn from NGC 5466 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field IMateu 2023, galstreams, MNRAS
A river of stars torn from NGC 6397 by the Milky Way's tide.Ibata et al. 2021, Charting the Galactic acceleration field IMateu 2023, galstreams, MNRAS
A river of stars torn from Omega Centauri by the Milky Way's tide.Ibata et al. 2019, Nature Astronomy, stream of omega CentauriIbata et al. 2021, Charting the Galactic acceleration field I
A river of stars torn from Palomar 13 by the Milky Way's tide.Shipp et al. 2020, AJ, tidal tails around Palomar 13
A river of stars torn from Palomar 15 by the Milky Way's tide.Myeong et al. 2017, ApJL, tidal tails around Eridanus and Palomar 15Mateu 2023, galstreams, MNRAS
A river of stars torn from Palomar 5 by the Milky Way's tide.Bonaca et al. 2020, tidal tails of Palomar 5Ibata et al. 2021, Charting the Galactic acceleration field I
A river of stars torn from Tucana III by the Milky Way's tide.Li et al. 2018, ApJ, the Tucana III stream

Trojan asteroids4 traced

Shares mars's orbit, L5, held by the Sun's and mars's pullIAU Minor Planet Center, list of Mars TrojansNASA Science, What is a Lagrange Point?
Shares mars's orbit, L4, held by the Sun's and mars's pullIAU Minor Planet Center, list of Mars TrojansNASA Science, What is a Lagrange Point?
Shares neptune's orbit, L4, held by the Sun's and neptune's pullIAU Minor Planet Center, list of Neptune TrojansNASA Science, What is a Lagrange Point?
Shares neptune's orbit, L5, held by the Sun's and neptune's pullIAU Minor Planet Center, list of Neptune TrojansNASA Science, What is a Lagrange Point?

Instruments6 traced

JunoCam: 58.000° (Juno)NAIF, JunoCam instrument kernel juno_junocam_v03.ti
LORRI: 0.290° (New Horizons)New Horizons PDS, LORRI instrument description
Hubble WFC3: 0.045° (UVIS)STScI, WFC3 Instrument Handbook 6.4; worked out from its numbers
JWST NIRCam: 0.037° (one module of two)STScI, JDox NIRCam field of view; worked out from its numbers
Binoculars: 7.000° (typical 7×50)Moore, S. L. 2012, 'Choosing and using binoculars for the travelling astronomer', J. Br. Astron. Assoc. 122, 11
Small telescope: 1.000° (low-power eyepiece)Coe, S., 'A Guide to Eyepieces, Part 1', Saguaro Astronomy Club (Novice's Corner)

Standing on a world7 traced

No air to speak of: the Sun and the stars share a black sky, as drawn.NASA, Moon facts
Under air ninety times Earth's and a deck of sulphuric-acid cloud the sky would be a yellowish overcast; the cloud is taken away here.NASA, Venus factsNSSDCA, Venus fact sheet
Mars's thin, dusty air makes the day sky hazy and red and hides the stars; it is taken away here (Graphics → Air from the ground brings it back).NASA, Mars factsNASA, Mars Pathfinder
A thin nitrogen air with a faint haze: the sky is drawn black here, without the haze (blue, at Pluto).NASA, Pluto factsNASA, Pluto's blue sky image article
Earth's air turns the daytime sky blue and hides the stars; it is taken away here (Graphics → Air from the ground brings it back).NASA Space Place, Why is the sky blue?StarDate (McDonald Observatory), Why aren't stars visible in the daytime?
There is no ground: you hang at the 1-bar level, where the air presses about as hard as Earth's at sea level, among layers of cloud and haze. They are taken away here.NASA Science, Jupiter: FactsNASA NSSDC, Jupiter Fact SheetNASA NSSDC, Earth Fact SheetJupiter equatorial cloud and ammonia profiles, VLT/MUSE + Cassini/VIMS + IRTF + Juno/JIRAM (arXiv abstract, 2026 preprint)Barstow et al. 2016, Probing Saturn's tropospheric cloud with Cassini/VIMS (arXiv abstract)Irwin et al. 2022, JGR Planets, Hazy blue worlds: aerosol model for Uranus and Neptune (arXiv abstract)
Titan's orange haze makes its sky from the ground a nearly featureless orange; it is taken away here (Graphics → Air from the ground brings it back).Barnes, MacKenzie, Lorenz & Turtle 2018, AJ 156, 247, Titan's Twilight and Sunset Solar IlluminationNASA Science, Titan: Facts

Pages on /space17 traced

voyager-1 flyby 0NSSDCA, Voyager planetary closest approachesNSSDCA, Voyager 1
voyager-1 flyby 1NSSDCA, Voyager planetary closest approachesNSSDCA, Voyager 1
voyager-1 flyby 2JPL Horizons vectors, read 2026-11-01; worked out from its numbers
voyager-2 flyby 0NSSDCA, Voyager planetary closest approachesNSSDCA, Voyager 2
voyager-2 flyby 1NSSDCA, Voyager planetary closest approaches
voyager-2 flyby 2NSSDCA, Voyager planetary closest approachesNSSDCA, Voyager 2JPL, Voyager 2 mission page
voyager-2 flyby 3NSSDCA, Voyager planetary closest approachesNSSDCA, Voyager 2JPL, Voyager 2 mission page
voyager-2 flyby 4JPL Horizons vectors, read 2026-11-01; worked out from its numbers
pioneer-10 flyby 0NSSDCA, Pioneer 10
pioneer-11 flyby 0NSSDCA, Pioneer 11
pioneer-11 flyby 1NSSDCA, Pioneer 11NASA, Pioneer 11
new-horizons flyby 0NSSDCA, New HorizonsNASA, New Horizons mission page
new-horizons flyby 1NSSDCA, New HorizonsStern 2008, Space Sci. Rev., New Horizons overview
new-horizons flyby 2JPL Horizons vectors, read 2026-11-01; worked out from its numbersNSSDCA, New Horizons
A 2025 study puts its period at about 12.4 days, nearly circular (arXiv 2510.12495).Regály, Fröhlich & Kiss 2025, accepted PASP
its long-term period is about 49.46 days (Ragozzine & Brown 2009).Ragozzine & Brown 2009, AJ
its long-term period is about 18.28 days (Ragozzine & Brown 2009), and Hi'iaka's pull changes it.Ragozzine & Brown 2009, AJ

Magnetic fields9 traced

tilt 0, field 190 nTAnderson et al. 2012, JGR 117 (NTRS); worked out from its numbers
tilt 9.200000000000003, field 30000 nTIGRF-14 coefficients, NOAA/IAGA; worked out from its numbersNOAA NCEI, wandering geomagnetic poles
tilt 10.3, field 417000 nTJRM09 coefficients, libinternalfield (github), crediting Connerney et al. 2018; worked out from its numbersConnerney et al. 2018, GRL (NTRS abstract)
tilt 0, field 21000 nTDougherty et al. 2018, Science 362Cassini 11 coefficients, libinternalfield (github), crediting Dougherty et al. 2018NSSDCA, Saturn fact sheet
its main aurora lies about 15° from the pole, where closed field lines give way to open ones (Cowley et al. 2004)Cowley et al. 2004, Ann. Geophys. 22, 1379
tilt 60, field 23000 nTNess et al. 1986, Science 233, 85; worked out from its numbers
tilt 47, field 13300 nTNess et al. 1989, Science 246, 1473; worked out from its numbers
tilt 4, field 720 nTKivelson et al. 2002, Icarus (NTRS); worked out from its numbers
its main oval maps to ~20–60 Jupiter radii (Bonfond et al. 2020)Bonfond, Yao & Grodent 2020, JGR Space Physics 125, e2020JA028152Bonfond et al. 2020, Same paper, arXiv

Quasars14 traced

Hyperluminous quasar. Its black hole is estimated at about 40 billion Suns (Ge et al. 2019) to about 66 billion (Shemmer et al. 2004), both from H-beta — estimates from broad-line scaling, not a direct measurement.Ge et al. 2019, AJ 157, 148Ge et al. 2019, the same paper free to read (arXiv)Shemmer et al. 2004, ApJ 614, 547Shemmer et al. 2004, the same paper free to read (arXiv)
Most distant quasar known at the time of discovery; BH mass (1.6+/-0.4)e9 Msun.Wang et al. 2021, ApJL 907, L1Wang et al. 2021, the same paper free to read (arXiv)
Wang, F. et al. 2021, ApJL 907, L1, "A Luminous Quasar at Redshift 7.642" (doi:10.3847/2041-8213/abd8c6)Wang et al. 2021, ApJL 907, L1Wang et al. 2021, the same paper free to read (arXiv)
800-million-solar-mass black hole at z=7.54.Banados et al. 2018, Nature 553, 473Banados et al. 2018, the same paper free to read (arXiv)
Banados, E. et al. 2018, Nature 553, 473 (doi:10.1038/nature25180)Banados et al. 2018, Nature 553, 473Banados et al. 2018, the same paper free to read (arXiv)
Gravitationally lensed, extremely luminous broad-absorption-line quasar.Ibata et al. 1999, arXiv:astro-ph/9908052Irwin et al. 1998, ApJ 505, 529
Irwin, M. J. et al. 1998, ApJ 505, 529 (discovery)Irwin et al. 1998, ApJ 505, 529
The lensing galaxy is at z ≈ 0.36.Fadely et al. 2010, ApJ 711, 246Fadely et al. 2010, the same paper free to read (arXiv)Chartas et al. 1998, ApJ 504, 661Chartas et al. 1998, the same paper free to read (arXiv)
Walsh, D., Carswell, R. F. & Weymann, R. J. 1979, Nature 279, 381 (first gravitational lens)Fadely et al. 2010, ApJ 711, 246Fadely et al. 2010, the same paper free to read (arXiv)Hainline et al. 2012, ApJ 744, 104Hainline et al. 2012, the same paper free to read (arXiv)
A quasar imaged four times by the bulge of a spiral galaxy at z = 0.039.Eigenbrod et al. 2008, arXiv:0810.0011
Huchra, J. et al. 1985, AJ 90, 691 (discovery)Eigenbrod et al. 2008, arXiv:0810.0011
The first quasar identified, and the brightest in our sky (V ≈ 12.9).ESA/Hubble potw1346a, Best image of bright quasar 3C 273Courvoisier 1998, The Bright Quasar 3C 273 (A&ARv 9, 1), NED Level 5
Schmidt, M. 1963, Nature 197, 1040 (first quasar redshift)Schmidt 1963, Nature 197, 1040, 3C 273: A Star-Like Object with Large Red-ShiftKellermann 2014, JAHH 17, 267 (arXiv:1304.3627), The Discovery of Quasars and its AftermathESA/Hubble potw1346a
Iriarte, B. & Chavira, E. 1957 (Tonantzintla survey); redshift via NEDAndernach et al. 2015 (arXiv:1504.07471), The Nature of Faint Blue Stars in the PHL and Ton CataloguesNED, TON 618 (FBQS J122824.9+312837)

Gravitational lenses18 traced

A quasar quadruply imaged by the bulge of a nearby barred spiral: …Eigenbrod et al. 2008, arXiv:0810.0011
A quasar doubly imaged (6.1 arcsec) by giant elliptical G1 + its cluster: …Kundic et al. 1997, arXiv:astro-ph/9610162Chartas et al. 1998, ApJ 504, 661Fadely et al. 2010, ApJ 711, 246
Fadely, R. et al. 2010, ApJ 711, 246 (lens galaxy G1 z = 0.361)Fadely et al. 2010, ApJ 711, 246Fadely et al. 2010, the same paper free to read (arXiv)Chartas et al. 1998, ApJ 504, 661Chartas et al. 1998, the same paper free to read (arXiv)
A near-complete Einstein ring of a star-forming galaxy around a luminous red galaxy: …Belokurov et al. 2007, ApJL 671, L9Belokurov et al. 2007, the same paper free to read (arXiv)
Belokurov, V. et al. 2007, ApJL 671, L9 (discovery)Belokurov et al. 2007, ApJL 671, L9Belokurov et al. 2007, the same paper free to read (arXiv)
A cluster lens with very many arcs; sources span a wide range of z, so no single source z is given: …Broadhurst et al. 2005, ApJ 621, 53Broadhurst et al. 2005, the same paper free to read (arXiv)
Broadhurst, T. et al. 2005, ApJ 621, 53 (HST/ACS strong-lensing analysis, >100 multiple images)Broadhurst et al. 2005, ApJ 621, 53Broadhurst et al. 2005, the same paper free to read (arXiv)
A dusty star-forming galaxy lensed into an Einstein ring: …ALMA Partnership 2015, ApJL 808, L4ALMA Partnership 2015, the same paper free to read (arXiv)Negrello et al. 2010, Science 330, 800Negrello et al. 2010, the same paper free to read (arXiv)
Negrello, M. et al. 2010, Science 330, 800 (Herschel discovery; z_lens 0.2999, z_source 3.042)Negrello et al. 2010, Science 330, 800Negrello et al. 2010, the same paper free to read (arXiv)ALMA Partnership 2015, ApJL 808, L4ALMA Partnership 2015, the same paper free to read (arXiv)
ALMA Partnership 2015, ApJL 808, L4 (long-baseline ALMA image)ALMA Partnership 2015, ApJL 808, L4ALMA Partnership 2015, the same paper free to read (arXiv)
A massive merging cluster at z = 0.87, lensing many arcs (their own redshifts are not listed here): …Menanteau et al. 2012, ApJ 748, 7Menanteau et al. 2012, the same paper free to read (arXiv)Frye et al. 2023, ApJ 952, 81Frye et al. 2023, the same paper free to read (arXiv)
Menanteau, F. et al. 2012, ApJ 748, 7 (El Gordo)Menanteau et al. 2012, ApJ 748, 7Menanteau et al. 2012, the same paper free to read (arXiv)
Frye, B. L. et al. 2023, ApJ, doi:10.3847/1538-4357/acd929 (JWST PEARLS: lensed arcs incl. "El Anzuelo")Frye et al. 2023, ApJ 952, 81Frye et al. 2023, the same paper free to read (arXiv)
A quasar quintuply imaged by a galaxy cluster: …Inada et al. 2005, arXiv:astro-ph/0503310
Inada, N. et al. 2003, Nature 426, 810 (cluster-lensed quasar, 14.6 arcsec; cluster z = 0.68)Inada et al. 2003, Nature 426, 810Inada et al. 2003, the same paper free to read (arXiv)
A cluster lens; first supernova resolved into multiple images: …Rodney et al. 2016, arXiv:1512.05734
Kelly, P. L. et al. 2015, Science 347, 1123 (multiply imaged supernova in a z = 1.49 spiral)Kelly et al. 2015, Science 347, 1123Kelly et al. 2015, the same paper free to read (arXiv)
Huchra, J. et al. 1985, AJ 90, 691 (discovery; lens galaxy z = 0.0394)Huchra et al. 1985, AJ 90, 691, 2237+0305: A new and unusual gravitational lensSluse et al. 2011, A&A 528, A100 (arXiv:1012.2871)W. Keel (Univ. of Alabama), The Einstein Cross gravitational lens 2237+030

Photographs65 traced

Hubble, visible light mosaicESA/Hubble heic0601a
ESO VLT, visible lightESO eso0202a
ESO La Silla, visible lightESO eso1105a
Wide-field photo, visible and hydrogen-alpha lightWikimedia Commons file page, Donatiello
ESO VISTA, infraredESO eso0949a
Kitt Peak, visible light; filaments of the Cygnus LoopNOIRLab noao-veil_filaments
Chandra, X-rayChandra Photo Album, Cassiopeia A, 2025
JWST, near-infrared; the ring around the explosionESA/Webb SN 1987A (NIRCam image)
Hubble, visible lightESA/Hubble heic1310a
Gemini North, visible lightNOIRLab geminiann10008a
JWST, near-infraredESA/Webb weic2207b
DECam at Cerro Tololo, visible lightNOIRLab noirlab2424a
Spitzer, infraredNASA Image Library PIA13843
Kitt Peak, visible lightNOIRLab noao-n1499block
JWST, near-infrared; the closest star-forming region to EarthESA/Webb weic2316a
Digitized Sky Survey 2, blue light; dark Coalsack beside the Jewel BoxESO jewel-box
WISE, infraredNASA Image Library PIA17553
ESO La Silla, visible light; gaps filled from the Digitized Sky SurveyESO eso0844a
Hubble, ultraviolet, visible and infrared lightESA/Hubble heic1321a
Kitt Peak, visible light; NGC 2158 beside itNOIRLab noao-m35
Optical, submillimetre and X-ray compositeESO eso0903a
Hubble with CFHT, visible and infrared lightESA/Hubble heic0602a
Event Horizon Telescope, radio at 1.3 mmESO eso2208-eht-mwaEHT Collaboration 2022, Sgr A* Paper I, arXiv text
Artist's impression: dormant black hole and Sun-like starNOIRLab noirlab2227a
Artist's impression: black hole and its companion starESO image eso2408a
Artist's impression: black hole feeding on its blue supergiantChandra photo album 2011, cygx1Chandra photo album 2009, cygx1
Chandra, X-ray; the pulsar and its jetChandra photo album 2013, vela
Chandra, X-ray; the pulsar's wind tailsChandra photo album 2017, gemingaPosselt et al. 2017
Hubble, visible light; Sirius B is the faint dotESA/Hubble image heic0516a
Artist's impression of a 2018 candidate planet, since shown false; not the planets found in 2024–25ESO image eso1837aLubin et al. 2021González Hernández et al. 2024, A&A 690, A79Basant et al. 2025
Artist's impression of Luhman 16B, from VLT weather mapsESO image eso1404c
Artist's impression of the coldest known brown dwarfNASA Image and Video Library PIA18001Luhman et al. 2024
Artist's diagram: Epsilon Eridani's belts beside our Solar SystemNASA Photojournal PIA11376
Hubble, ultraviolet and visible light; the Homunculus nebulaESA/Hubble image potw1208a
GALEX, ultraviolet; Mira's 13-light-year tailNASA Photojournal PIA09958
Artist's impression: a hypothetical uneven dust ring around the starNASA Image and Video Library PIA22081
Artist's impression from one of its planetsESO image eso1615a
Artist's impression of the hot Jupiter 51 Pegasi bESO image eso1517a
Artist's impression: the evaporating planet HD 209458 bESA/Hubble image heic0303b
Artist's impression of Kepler-186fNASA Image and Video Library PIA17999
Artist's impression of Kepler-452bNASA Image and Video Library PIA19825
Artist's impression of TOI 700 dNASA Photojournal PIA23408
JWST, infrared; star masked, its planets visibleESA/Webb image weic2504a
ESO 3.6-metre/ADONIS (disc) and VLT/NACO (planet), infraredESO image eso1024a
Artist's impression of K2-18 bESA/Webb image weic2321a
Artist's impression of 55 Cancri eNASA Image and Video Library PIA22069
Artist's impression of WASP-39 bESA/Webb image wasp39b-1
Artist's impression of LHS 1140bESO image eso1712a
Photo: a Voyager probe in vibration testing, 1976NASA Image and Video Library PIA21733
Photo: Voyager 2 before launch, August 1977NASA Image and Video Library PIA21743
Photo: Pioneer 10 readied for launch, 1972NASA Image and Video Library ARC-1972-AC72-2135
Photo: Pioneer 11 (Pioneer G) before launch, 1973NASA Image and Video Library KSC-73P-0116
Photo: New Horizons at Kennedy Space Center, 2005NASA Image and Video Library KSC-05pd2494
Artist's concept: our galaxy seen face-onNASA Image and Video Library PIA10748
Hubble with Las Campanas; ultraviolet to near-infrared compositeESA/Hubble image heic1403b
DECam Legacy Surveys, visible lightNOIRLab image noirlab2620a
Kitt Peak Mayall 4 m, visible lightNOIRLab image noirlab2112b
ESO La Silla 2.2 m, visible lightESO image eso1037a
Kitt Peak 2.1 m, 1973 black-and-white photographNOIRLab image noao-02286
Kitt Peak Mayall 4 m, 1975 black-and-white photographNOIRLab image noao-02287
Kitt Peak Mayall 4 m, visible and hydrogen-alpha lightNOIRLab image noao-ngc6946kpno
ESO VST, visible and near-infrared light; Leo Triplet fieldESO image eso1126a
ESO VST, ultraviolet, visible and infrared lightESO eso2214a
DECam SMASH survey, visible and infrared lightNOIRLab noirlab2030a
Kitt Peak 0.9 m, 1991NOIRLab image noao-m74, M74 (NGC 628), credit Todd Boroson/NOIRLab/NSF/AURA (fields read via the AstroPix mirror; noirlab.edu rendered empty)NOIRLab, noao-m74

Captions in the view43 traced

its path from Sagittarius A* · 4.8 million yearsKoposov et al. 2020
A model built from published measurements — Courteau et al. 2011, Gordon et al. 2006, McConnachie 2012, Ibata et al. 2001Courteau et al. 2011, ApJ 739, 20Gordon et al. 2006, ApJ 638, L87McConnachie 2012, AJIbata et al. 2001, Nature 412, 49
A model built from published measurements — the arms of Reid et al. 2019; star-forming regions, globular clusters and satellites as measuredReid et al. 2019, ApJBaumgardt, globular cluster database
Our galaxy, from above its north pole. The Sun is about 27,000 light-years from the centre.GRAVITY Collaboration 2019, A&A 625, L10; worked out from its numbers
The Sun and its eight planets, where each one is today, with the dwarf planets beyond Neptune. Tap a world for its card.NASA, Solar System Facts
The Andromeda Galaxy, M31 — the nearest big spiral to ours, about 2.5 million light-years away. From Earth we see its disc tilted 77° from face-on; here, from much nearer its pole.NASA, Messier 31
All round the Sun — we are inside it. Tap it for its card.Zucker et al. 2022, Nature 601, 334
Gamma rays, as Fermi sees them: cosmic rays lighting the gas — and the Fermi bubbles, rising 25,000 light-years from the centre. Shown in false colour.NASA, Fermi bubbles release, 2010Fermi-LAT Collaboration 2012
The whole Milky Way, about 100,000 light-years across, and the Sun inside it.NASA, GalaxiesNASA, Fermi bubbles release, 2010
Andromeda, the namesake: a spiral of about a trillion stars, 2.5 million light-years from home.NASA, Hubble Traces Hidden History of Andromeda GalaxyNASA, Messier 31
From its double heart to the planet candidate and the streams in its halo — every stop measured.Bender et al. 2005Ingrosso et al. 2009, MNRAS 399, 219McConnachie et al. 2018
the black hole at the centreESO, eso2208, Sagittarius A* image
the whole galaxy, 2.5 million lyNASA, Messier 31
Shue et al. 1998, from the windShue et al. 1998, JGR 103, 17691
Io's flux tube: a current of ~3 million amps to its own aurora spot (LNASA, Io facts
Io's plasma torus — sulphur and oxygen from its volcanoes, ~1 tonne a second (model)Roth et al. 2025, Mass supply from Io to Jupiter's magnetosphere, arXiv:2403.13970 (Space Science Reviews (2025))
The Sun's field, wound by its turning — the spiral's pitch from the windNOAA SWPC, Solar Wind
The five balance points of Sun–Earth, Earth–Moon and Sun–Jupiter, and the zero-velocity curves round them.NASA, What is a Lagrange Point?
Orbits locked in whole-number rhythms: the Kirkwood gaps, the Cassini Division, Io–Europa–Ganymede, Neptune–Pluto.JPL SSD, Main Asteroid Belt histogramHedman et al. 2010, The Architecture of the Cassini Division, arXiv:0911.2438 (The Astronomical Journal 139 (2010) 228-251)Yap & Batygin 2025, arXiv:2601.00786, Callisto's Nonresonant Orbit (The Astrophysical Journal, 995(2), 218 (2025))NASA Science, Kuiper Belt: Facts
Where the Solar System balances — the Sun goes round it — and Pluto–Charon's and Earth–Moon's.NASA Space Place, What is a barycenter?Gakis & Gourgouliatos 2022, arXiv:2202.13319, Orbit determination of the moons of the Pluto-Charon system (Celestial Mechanics and Dynamical Astronomy 134, 14 (2022), 1-18)NOAA Tides and Currents, Our Restless Tides
Each world's full shadow (umbra), where the Sun is completely blocked, and partial shadow (penumbra), where it is partly hidden.NASA Science, Eclipses
Each planet's measured field as lines turning with it — Uranus's and Neptune's tilted and off-centre — with Jupiter's and Saturn's auroral ovals, Io's flux tube, and Earth's magnetopause where today's solar wind meets it. Models, from the missions that measured them.NSSDCA Uranus Fact SheetNSSDCA Neptune Fact SheetRoth et al. 2025, Mass supply from Io to Jupiter's magnetosphere, arXiv:2403.13970 (Space Science Reviews (2025))Lamy et al. 2013, arXiv:1307.4675, Multi-spectral simultaneous diagnosis of Saturn's auroraeNOAA SWPC, Earth's Magnetosphere
Every star Ouranos draws, plotted by colour against true brightness (from its measured brightness and distance): the main sequence, the giants and the white dwarfs appear on their own, the Sun among them.ESA, Gaia creates richest star map of our Galaxy and beyondESA, Hipparcos H-R diagramsGaia Collaboration 2018, Observational Hertzsprung-Russell diagrams, arXiv:1804.09378
The picked planet's orbit if its speed today were nudged: 10% slower falls inwards, 10% faster swings out, at its escape speed it leaves the Sun — Newton's two-body orbits, exactly.NASA, Basics of Space Flight, chapter 4; worked out from its numbersHyperPhysics, Escape Velocity
Light takes time: each world is drawn where it is now, and a ghost shows where you actually see it — where it was when the light now reaching you left it (Jupiter from Earth: 33 to 54 minutes behind).NSSDCA Jupiter Fact Sheet; worked out from its numbers
What each instrument takes in from here, at its true size on the sky: binoculars, a small telescope, New Horizons's LORRI, Hubble's WFC3, Webb's NIRCam, JunoCam. Zoom in and the narrow ones grow. Fields of view: STScI, NASA, New Horizons PDS, Hansen et al. 2017; binoculars and telescope typical.New Horizons PDS, LORRI instrument overviewSTScI, WFC3 Instrument Handbook, section 2.1STScI JDox, NIRCam Field of ViewHansen et al. 2017, Space Sci Rev 213, 475 (Junocam: Juno's Outreach Camera)
Cassini Division · inner edge near Mimas 2:1Hedman et al. 2010, The Architecture of the Cassini Division, arXiv:0911.2438 (The Astronomical Journal 139 (2010) 228-251)
Io : Europa : Ganymede = 1 :Yap & Batygin 2025, arXiv:2601.00786, Callisto's Nonresonant Orbit (The Astrophysical Journal, 995(2), 218 (2025))
Earth and Moon circle this point — inside the EarthNOAA Tides and Currents, Our Restless Tides
Enceladus's plumes — water vapour and ice from its south pole, ~300 kg a second of vapour, blazing backlitVillanueva et al. 2023, JWST mapping of Enceladus' plume, arXiv:2305.18678NASA Science, Enceladus
Graveyard orbit · 300 km higherESA, Graveyard orbit 300 km above GEO
How far our signals have spread at the speed of light: Marconi's first radio across an ocean (1901), television from the Berlin Olympics (1936), and the Arecibo message on its way to M13 (1974). How far, not who could hear.IEEE Milestone, Reception of Transatlantic Radio Signals, 1901; worked out from its numbersCornell Chronicle, 25th anniversary of the Arecibo messageEarly Television Museum, German prewar televisionForgan & Nichol 2010, A Failure of Serendipity, arXiv:1007.0850
The Sun's magnetic field carried out by the solar wind and wound into a spiral by its turning — its pitch from the latest measured wind (NOAA), and gone when that is hours old.NOAA SWPC, Solar Wind
Our first radio across an ocean (Marconi, 1901)IEEE Milestone, Reception of Transatlantic Radio Signals, 1901
Television from the Berlin Olympics (1936)Early Television Museum, German prewar television
43,390 galaxies of the 2MASS Redshift Survey, 95% of them within about 830 million light-years and the farthest about 1.4 billion: clusters, the filaments between them, and the voids. Their distances come from redshift, so each cluster is stretched along our line of sight.Coil, A. L., 'Large Scale Structure of the Universe', NASA/IPAC Extragalactic Database (NED) Level 5, section 4
From here the Sun is too faint to see with the naked eye.Texas Parks and Wildlife Department, Astronomy Definitions (Magnitude; NELM)NASA HEASARC, Yale Bright Star Catalog (BSC5P) description
Hydrogen, at 21 cm: the gas the stars are eventually made from, reaching far past them. Radio light, shown in false colour.McClure-Griffiths, Stanimirović & Rybarczyk 2023, 'Atomic Hydrogen in the Milky Way: A Stepping Stone in the Evolution of Galaxies', ARA&A 61
The stars as you'd see them flying at 90% of light speed towards where you look: crowded, bluer and brighter ahead, the sky behind thinning and darkening (special relativity, exactly — the photographs behind them are not shifted).Lagoute, C. & Davoust, E. 1995, 'The interstellar traveler', Am. J. Phys. 63, 221
At 90% of light speed towards the centre: the stars crowd ahead, bluer and brighter — special relativityLagoute, C. & Davoust, E. 1995, 'The interstellar traveler', Am. J. Phys. 63, 221
The picked world's orbit cut into slices it sweeps in equal times — faster when nearer — and the third law plotted: every planet's year against its distance, on one line.NASA NSSDCA, Planetary Fact Sheet (distance from the Sun and orbital period of all eight planets; the line worked out from its numbers)
The two bulges the Moon raises on Earth, hugely exaggerated, and what they do: Earth's turning carries them ahead of the Moon, and their pull moves the Moon 3.83 cm further away every year (lunar laser ranging). The Moon keeps one face to us, its own spin long since slowed by Earth's tides on it.Maeder & Gueorguiev 2021, On the Relation of the Lunar Recession and the Length-of-the-Day (Astrophys. Space Sci. 366, 101): 38.30 ± 0.09 mm/yr from 20,138 laser ranges, 1970–2015, after Williams et al. 2016 and Williams & Boggs 2016
Kepler's third law: year² ∝ distance³ — the eight planets' semi-major axes and sidereal periods on one line of slope 1.5NASA NSSDCA, Planetary Fact Sheet; the slope worked out from its numbers

Eclipses and transfers1 traced

Hohmann transfers between the planets' orbits taken as circles at their mean distances; the burns are orbit to orbit round the Sun (escaping the Earth and arriving at the target cost more). Windows from the planets' real positions: the craft arrives at the target's real longitude, but the path ends at its mean distance from the Sun, so it misses by the difference between that and where the planet really is then. Real missions fly exact paths: seven NASA and ESA launches to Mars, 2005-2020, went from 7 weeks before these windows to 3 weeks after.NASA, Mars Reconnaissance Orbiter; worked out from its numbersNASA, PhoenixNASA, CuriosityNASA, MAVENESA, ExoMars programme overviewNASA, InSightNASA, Perseverance

Sagittarius A*1 traced

The black hole at the centre of our galaxy: 4.3 million Suns, weighed by the stars that orbit it.GRAVITY Collaboration 2022, A&A, arXiv:2112.07478Gillessen et al. 2017, ApJ, arXiv:1611.09144

Pulsars2 traced

A spinning neutron star sweeping a radio beam past us; its distance measured by parallax.NASA Imagine the Universe, Neutron StarsDeller et al. 2019, ApJ 875, 100, arXiv:1808.09046
A neutron star with the strongest magnetic field known, given to violent outbursts.ESO, eso1415Magnetars, arXiv:1703.00068

Milky Way's dwarf galaxies3 traced

A small satellite galaxy of ours.Pace 2025, The Local Volume Database, arXiv:2411.07424
A candidate satellite galaxy — not yet confirmed.Pace 2025, The Local Volume Database, arXiv:2411.07424
A faint satellite: whether it is a galaxy or a star cluster is not yet settled.Pace 2025, The Local Volume Database, arXiv:2411.07424

Star-forming regions1 traced

Hydrogen glowing round newborn massive stars — these trace the spiral arms.Anderson et al. 2014, ApJS, arXiv:1312.6202

Andromeda's globular clusters1 traced

A ball of hundreds of thousands of old stars orbiting Andromeda — older than the Sun by billions of years.Caldwell et al. 2011, AJ 141, 61, arXiv:1101.3779; worked out from its numbersNASA Science, Sun: Facts

Local Group objects2 traced

What is left of a star that exploded.NASA Imagine the Universe, Supernova RemnantsMaggi et al. 2016, A&A 585, A162, arXiv:1509.09223NASA Imagine the Universe, Supernovae: "the explosion of a star"
Glowing gas lit by young, hot stars — a place where stars are being born.NASA, Messier 33Anderson et al. 2014, ApJS, arXiv:1312.6202

The Local Volume1 traced

Placed at its catalogued distance. No telescope's map of it is shown here: its look is drawn from its type, size and tilt.Karachentsev, Makarov & Kaisina 2013, AJ, arXiv:1303.5328

The oldest light1 traced

The afterglow of the Big Bang, cooled to 2.7 degrees above absolute zero…Fixsen 2009, arXiv:0911.1955NASA, WMAP overview

Fast radio bursts1 traced

In a globular cluster of M81, 3.6 Mpc away; M81 is approaching us slightly, so its distance is M81’s measured one, not one from redshift.Kirsten et al. 2021, A repeating fast radio burst source in a globular cluster, arXiv:2105.11445SIMBAD, M 81 (radial velocity -47 km/s)

Galaxy clusters1 traced

A cluster of hundreds to thousands of galaxies, held together by its dark matter.NASA, Messier 87Chandra X-ray Center, Galaxy Clusters

The line card2 traced

A line on the chart joins two stars that may have nothing to do with each other.NASA Space Place, What Are Constellations?
Each star's light left at a different time. Each bar is as wide as the measurement allows.NASA Space Place, What Are Constellations?

Moons2 traced

Artist's impression: it has been photographed, but not mapped here. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.NASA Science, Metis
Artist's impression: no close-up image of it is used here. This look is generated from many factors as a best guess at what it might look like, and will be updated as more data comes in.NASA Science, ThemistoNASA Science, Telesto (counter-example)NASA Science, Calypso (counter-example)

The universe through time38 traced

The Planck time, 5.39 × 10⁻⁴⁴ seconds. At times this short, quantum effects and gravity both matter, and only a theory of quantum gravity could describe what happens.NIST, CODATA: the Planck timeMax Planck Institute for Gravitational Physics, Einstein Online: Planck time
What happened here is not known. No experiment reaches these energies.NIST, CODATA: the Planck timeMax Planck Institute for Gravitational Physics, Einstein Online: Planck time
The leading idea: a burst of accelerating expansion that smoothed space and seeded the ripples that later became galaxies.Particle Data Group 2024, Inflation (Ellis & Wands)Planck Collaboration 2018 X, Constraints on inflation
Not confirmed, and not dated: its energy could lie anywhere below Planck's limit of about 10¹⁶ GeV, so its place on this bar is a placeholder. The ripples it predicts are consistent with what Planck measured.Particle Data Group 2024, Inflation (Ellis & Wands)Planck Collaboration 2018 X, Constraints on inflation
Beyond the energies colliders have tested. The numbers shown assume only the particles we know, and that the hot era reached this far back; they are an extrapolation.Particle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)Husdal 2016, On Effective Degrees of Freedom in the Early Universe
Every kind of particle in the Standard Model is present, all moving near the speed of light.Particle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)Husdal 2016, On Effective Degrees of Freedom in the Early Universe
At about 160 GeV (159.6 ± 0.1 ± 1.5), 9.2 × 10⁻¹² seconds in, the electromagnetic and weak forces part ways and particles gain their masses from the Higgs field: a smooth crossover, from lattice calculations.D'Onofrio & Rummukainen 2016, Standard Model cross-over on the latticeParticle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)Husdal 2016, On Effective Degrees of Freedom in the Early Universe
Quarks and gluons still roam free. From here on, the physics is the kind particle colliders have tested.D'Onofrio & Rummukainen 2016, Standard Model cross-over on the latticeParticle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)Husdal 2016, On Effective Degrees of Freedom in the Early Universe
At about 156.5 MeV, 1.8 × 10⁻⁵ seconds in, quarks and gluons bind into protons, neutrons and other hadrons: a crossover, from lattice QCD.HotQCD, Bazavov et al. 2019, Chiral crossover in QCDParticle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)Husdal 2016, On Effective Degrees of Freedom in the Early Universe
Around a second in, at about 1 MeV, neutrinos stop interacting and stream away. They still fill space today, at about 1.9 K.HotQCD, Bazavov et al. 2019, Chiral crossover in QCDParticle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)Husdal 2016, On Effective Degrees of Freedom in the Early Universe
Electrons and positrons annihilate, heating the light. Below about 0.1 MeV nuclei can survive: protons and neutrons fuse into helium in a rush between about three and five minutes, with a little deuterium and lithium; by about twenty minutes the amounts are set.Particle Data Group 2024, Big-Bang Nucleosynthesis (Fields, Molaro & Sarkar)Particle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)
Measured: a quarter of the ordinary matter by mass became helium (0.245 ± 0.003), as gas in little-evolved galaxies still shows.Particle Data Group 2024, Big-Bang Nucleosynthesis (Fields, Molaro & Sarkar)Particle Data Group 2024, Big-Bang Cosmology (Olive & Peacock)
Too hot for atoms: free electrons scatter every particle of light, so the universe glows but cannot be seen through. About 51,000 years in, matter starts to outweigh light and neutrinos together.Planck Collaboration 2018 VI, Cosmological parameters, Table 2ESA, Planck and the cosmic microwave background
Its tiny ripples, a few parts in a hundred thousand, are shown exaggerated so you can see them.Planck Collaboration 2018 VI, Cosmological parameters, Table 2ESA, Planck and the cosmic microwave background
About 370,000 years in, at about 3,000 K, electrons join nuclei into atoms and the fog clears. The light set free then still reaches us as the cosmic microwave background.Planck Collaboration 2018 VI, Cosmological parameters, Table 2ESA, Planck and the cosmic microwave backgroundNASA LAMBDA, WMAP nine-year ILC map
Measured: WMAP's map of that light, its warm and cool patches exaggerated thousands of times.Planck Collaboration 2018 VI, Cosmological parameters, Table 2ESA, Planck and the cosmic microwave backgroundNASA LAMBDA, WMAP nine-year ILC map
By about 3.1 million years in, the leftover glow has cooled below roughly 798 K, about where a hot thing stops glowing visibly. To an eye, the universe goes dark.Draper 1847, On the production of light by heat (Scientific Memoirs, 1878)Bromm 2013, Formation of the first starsKlessen & Glover 2023, The first starsVisbal, Hazlett & Bryan 2025, LAP1-B, a Population III candidateBowman et al. 2018, EDGES absorption profileSingh et al. 2022, SARAS 3 rejects the EDGES profile
Matter, invisible, gathers under gravity. The first stars are thought to form from about 100 million years in: theory, never yet seen. One candidate, LAP1-B, seen much later (about 800 million years in), is not confirmed.Draper 1847, On the production of light by heat (Scientific Memoirs, 1878)Bromm 2013, Formation of the first starsKlessen & Glover 2023, The first starsVisbal, Hazlett & Bryan 2025, LAP1-B, a Population III candidateBowman et al. 2018, EDGES absorption profileSingh et al. 2022, SARAS 3 rejects the EDGES profile
A radio signal claimed from this era (EDGES, 2018) is disputed: SARAS 3 found no sign of it, rejecting its shape at 95% confidence.Draper 1847, On the production of light by heat (Scientific Memoirs, 1878)Bromm 2013, Formation of the first starsKlessen & Glover 2023, The first starsVisbal, Hazlett & Bryan 2025, LAP1-B, a Population III candidateBowman et al. 2018, EDGES absorption profileSingh et al. 2022, SARAS 3 rejects the EDGES profile
Galaxies are shining. The farthest measured, MoM-z14, is seen as it was about 280 million years in.Naidu et al. 2025, MoM-z14Elbers 2025, Rapid late-time reionization: a fit to the measurements (midpoint z = 7.00)Qin et al. 2025, reionization ends at z = 5.44, midpoint z = 7.7Planck Collaboration 2018 VI, Cosmological parameters, Table 2Mason et al. 2018, 0.59 neutral at z ~ 7Greig et al. 2024, quasar damping wings: 0.20 neutral at z = 6.15Spina et al. 2024, 0.19 ± 0.07 neutral at z = 5.6Umeda et al. 2025, JWST damping wings of 581 galaxiesNakane et al. 2024, JWST Lyα: 0.93 neutral at z ~ 9–13Bosman et al. 2022, Hydrogen reionisation ends by z = 5.3Xiang & Rix 2022, A time-resolved picture of our Milky Way's early formation history
Their starlight splits the hydrogen between galaxies again: reionization, about half done by z ≈ 7 to 7.7 (670 million years to 760 million years in), still about a fifth neutral near z ≈ 6, and finished by about 1.1 billion years, when its last fluctuations fade from quasars' light.Naidu et al. 2025, MoM-z14Elbers 2025, Rapid late-time reionization: a fit to the measurements (midpoint z = 7.00)Qin et al. 2025, reionization ends at z = 5.44, midpoint z = 7.7Planck Collaboration 2018 VI, Cosmological parameters, Table 2Mason et al. 2018, 0.59 neutral at z ~ 7Greig et al. 2024, quasar damping wings: 0.20 neutral at z = 6.15Spina et al. 2024, 0.19 ± 0.07 neutral at z = 5.6Umeda et al. 2025, JWST damping wings of 581 galaxiesNakane et al. 2024, JWST Lyα: 0.93 neutral at z ~ 9–13Bosman et al. 2022, Hydrogen reionisation ends by z = 5.3Xiang & Rix 2022, A time-resolved picture of our Milky Way's early formation history
About 0.8 billion years in, the Milky Way's old, thick disc starts to form, dated by its stars' ages.Naidu et al. 2025, MoM-z14Elbers 2025, Rapid late-time reionization: a fit to the measurements (midpoint z = 7.00)Qin et al. 2025, reionization ends at z = 5.44, midpoint z = 7.7Planck Collaboration 2018 VI, Cosmological parameters, Table 2Mason et al. 2018, 0.59 neutral at z ~ 7Greig et al. 2024, quasar damping wings: 0.20 neutral at z = 6.15Spina et al. 2024, 0.19 ± 0.07 neutral at z = 5.6Umeda et al. 2025, JWST damping wings of 581 galaxiesNakane et al. 2024, JWST Lyα: 0.93 neutral at z ~ 9–13Bosman et al. 2022, Hydrogen reionisation ends by z = 5.3Xiang & Rix 2022, A time-resolved picture of our Milky Way's early formation history
Star-making peaks at "cosmic noon", about 3.5 billion years in, at about 9 times today's rate. Bright quasars are most common between about 2.1 billion years and 3.3 billion years after the Big Bang.Madau & Dickinson 2014, Cosmic Star-Formation HistoryRichards et al. 2006, the SDSS quasar luminosity functionHelmi et al. 2018, The merger that led to the formation of the Milky Way's inner stellar halo and thick diskXiang & Rix 2022, A time-resolved picture of our Milky Way's early formation history
Between 10 and 11 billion years ago, the Milky Way swallows a smaller galaxy, Gaia-Enceladus, whose stars still move through our halo.Madau & Dickinson 2014, Cosmic Star-Formation HistoryRichards et al. 2006, the SDSS quasar luminosity functionHelmi et al. 2018, The merger that led to the formation of the Milky Way's inner stellar halo and thick diskXiang & Rix 2022, A time-resolved picture of our Milky Way's early formation history
About 8 billion years ago, the Milky Way's star-making changes sharply, to a later, quieter phase of disc building.Madau & Dickinson 2014, Cosmic Star-Formation HistoryRichards et al. 2006, the SDSS quasar luminosity functionHelmi et al. 2018, The merger that led to the formation of the Milky Way's inner stellar halo and thick diskXiang & Rix 2022, A time-resolved picture of our Milky Way's early formation history
The expansion stops slowing and starts to speed up: about 7.6 billion years in by the Planck 2018 model (z ≈ 0.64); kinematic and cosmology-independent measurements, less precise, put it a little later (z ≈ 0.4 to 0.5). Dark energy comes to outweigh matter later still, about 3.6 billion years ago (z ≈ 0.3), by the same model.Planck Collaboration 2018 VI, Cosmological parameters, Table 2Riess et al. 2004, the transition from deceleration to accelerationMoresco et al. 2016, cosmic chronometersConnelly et al. 2012, Science: the absolute chronology of the first solidsValley et al. 2014, Nature Geoscience: a 4.4-billion-year-old zirconAllwood et al. 2006, Stromatolite reef from the Early Archaean era of Australia
4.567 billion years ago, about 9.2 billion years in, the Solar System's oldest solids form, round the young Sun.Planck Collaboration 2018 VI, Cosmological parameters, Table 2Riess et al. 2004, the transition from deceleration to accelerationMoresco et al. 2016, cosmic chronometersConnelly et al. 2012, Science: the absolute chronology of the first solidsValley et al. 2014, Nature Geoscience: a 4.4-billion-year-old zirconAllwood et al. 2006, Stromatolite reef from the Early Archaean era of Australia
Earth's oldest known mineral grain is 4.4 billion years old. Stromatolites 3.43 billion years old, layered mounds of probable biological origin, are among the oldest signs of life.Planck Collaboration 2018 VI, Cosmological parameters, Table 2Riess et al. 2004, the transition from deceleration to accelerationMoresco et al. 2016, cosmic chronometersConnelly et al. 2012, Science: the absolute chronology of the first solidsValley et al. 2014, Nature Geoscience: a 4.4-billion-year-old zirconAllwood et al. 2006, Stromatolite reef from the Early Archaean era of Australia
In about a billion years the Sun has brightened enough that Earth leaves its habitable zone.Schröder & Smith 2008, Distant future of the Sun and Earth revisitedSawala et al. 2025, Nature Astronomy 9, 1206: No certainty of a Milky Way–Andromeda collision (open access)DESI Collaboration 2025, DR2 baryon acoustic oscillations
Andromeda and the Milky Way may not collide after all: a 2025 study finds close to even odds of no merger in the next 10 billion years, and only about a 1 to 2% chance of one within 5 billion (read from the paper's Figure 3).Schröder & Smith 2008, Distant future of the Sun and Earth revisitedSawala et al. 2025, Nature Astronomy 9, 1206: No certainty of a Milky Way–Andromeda collision (open access)DESI Collaboration 2025, DR2 baryon acoustic oscillations
This forecast assumes dark energy stays constant. DESI's 2025 measurements prefer one that changes, at 3.1σ with the CMB and 2.8 to 4.2σ adding supernovae: a hint, not yet a detection.Schröder & Smith 2008, Distant future of the Sun and Earth revisitedSawala et al. 2025, Nature Astronomy 9, 1206: No certainty of a Milky Way–Andromeda collision (open access)DESI Collaboration 2025, DR2 baryon acoustic oscillations
About 5.4 billion years from now the Sun runs out of hydrogen in its core and swells into a red giant.Schröder & Smith 2008, Distant future of the Sun and Earth revisitedSawala et al. 2025, Nature Astronomy 9, 1206: No certainty of a Milky Way–Andromeda collision (open access)
About 7.6 billion years from now it is at its largest, its radius about 1.2 au: Earth is engulfed. If the two galaxies merge, the median time is about 7.6 billion years from now too.Schröder & Smith 2008, Distant future of the Sun and Earth revisitedSawala et al. 2025, Nature Astronomy 9, 1206: No certainty of a Milky Way–Andromeda collision (open access)
Space speeds up, and every galaxy beyond our own group is carried past our horizon, on a timescale of about 100 billion years.Krauss & Scherrer 2007, The return of a static universeLoeb 2002, The long-term future of extragalactic astronomy
By then the leftover glow is stretched toward radio waves: by this model it peaks at about 16 cm at 100 billion years, 9 orders of magnitude fainter than today (Krauss & Scherrer 2007 put it nearer 1 m and 12 orders around then).Krauss & Scherrer 2007, The return of a static universeLoeb 2002, The long-term future of extragalactic astronomy
The gas runs out. By about 10¹⁴ years essentially all normal star formation has ceased.Adams & Laughlin 1997, A dying universe (Rev. Mod. Phys.)Adams, Laughlin & Graves 2004, Red dwarfs and the end of the main sequence
The longest-lived stars are the smallest red dwarfs: one of 0.08 solar masses shines for about 12 trillion years, and none ever becomes a red giant.Adams & Laughlin 1997, A dying universe (Rev. Mod. Phys.)Adams, Laughlin & Graves 2004, Red dwarfs and the end of the main sequence
Today: 13.8 billion years. Light from every era since the oldest light is still arriving.Planck Collaboration 2018 VI, Cosmological parameters, Table 2