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Globular cluster

Messier 55

Also M55 · NGC 6809

Open in OuranosCompare its size

A globular cluster: around 100,000 or more very old stars in a tight ball, orbiting the Milky Way's centre.

Measured

Distance
17,450 light-years
Size
about 96 light-years across (approximate)
Constellation
Sagittarius
Position (J2000)
RA 19h 39m 59s, Dec −30.96°

How far, from the Sun

17,500 light-years. To cross it:

  • Light17,500 years
  • Voyager 1's speed310 million years
  • Driving at 100 km/h188 billion years

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Facts

  • Nicolas-Louis de Lacaille found it around 1751–52 from South Africa.
  • It holds about 197,000 times the Sun's mass in stars (Baumgardt's globular cluster database).

Where this comes from

  • Baumgardt & Vasiliev 2021, MNRAS 505, 5957 (5.35 kpc; the distances in public/sky/galaxy/globulars.json)
  • This research has made use of the SIMBAD database, CDS, Strasbourg, France (Wenger et al. 2000, A&AS 143, 9).
  • This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France (DOI: 10.26093/cds/vizier).

Every catalogue Ouranos draws is credited on the credits page.