Side by side

Two things at their true relative size. Pick any two that have a measured size.

First

Second

Earth beside Jupiter Earth and the Moon The Sun beside VY Canis Majoris The Sun beside Sgr A*'s shadow The ISS beside Webb The Orion Nebula beside Andromeda

Phobos

22.2 km — its mean width

Too small to see at this scale; ringed.

Earth

12,800 km — its width at the equator

Earth is 575 times as wide as Phobos.

About 190 million of Phobos would fit inside Earth.

Phobos: Mean radius: JPL planetary and satellite physical parameters (lib/ouranosSolarSystem)
Earth: Equatorial radius: JPL planetary and satellite physical parameters (lib/ouranosSolarSystem)

Any distance, three ways

4.25 light-years:

Light4.25 years
Voyager 1's speed75,400 years
Driving at 100 km/h45.8 million years

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling. The nearest star, Proxima Centauri, is 4.246 light-years away.