Callisto
Moon of Jupiter
Jupiter’s second-largest moon, a dark world covered in more craters than any other object in the Solar System.
Key facts
- Orbits
- Jupiter
- Diameter
- About 4,821 km
- One orbit
- 16.7 days
- Notable for
- Most heavily cratered object in the Solar System
About the Callisto
How to recognise it
Callisto is dark brownish-grey and peppered with bright spots, which are fresh craters exposing ice beneath the surface.
What makes it special
NASA calls Callisto the most heavily cratered object in the Solar System. Its ancient surface has changed very little for billions of years. It is the third-largest moon in the Solar System.
Sources
Facts checked: 29 October 2026
