Callisto
Jupiter's second-largest moon with the most cratered surface in the solar system.
About
Callisto is the second-largest moon of Jupiter and the third-largest moon in the solar system. It has the most heavily cratered surface of any body in the solar system, indicating an ancient and geologically inactive surface. It may also harbor a subsurface ocean.
Properties
Notable Facts
Callisto has the most heavily cratered surface of any object in the solar system
Its surface is estimated to be about 4 billion years old
It orbits beyond Jupiter's main radiation belt, making it a candidate for a future human base
Despite its ancient surface, it may harbor a subsurface ocean
Other Moons of Jupiter
Io
The most volcanically active body in the solar system and innermost Galilean moon.
3,643.2 km
Diameter
1.8 d
Orbit
1610
Discovered
Europa
Jupiter moon with a subsurface ocean considered a prime candidate for extraterrestrial life.
3,121.6 km
Diameter
3.6 d
Orbit
1610
Discovered
Ganymede
The largest moon in the solar system, bigger than Mercury, with its own magnetic field.
5,268.2 km
Diameter
7.2 d
Orbit
1610
Discovered