Jupiter‘s moon Ganymede is the largest moon in the solar system, and is larger even than the planet Mercury, although less than half as massive.

Ganymede is the third of the four Galilean moons, in terms of increasing distance from Jupiter, discovered by Galileo Galilei – along with Io, Europa and Callisto – in 1610.

Ganymede’s surface is composed of light and dark grey regions, covered in impact craters. The lighter regions are also crisscrossed with grooves that are likely to be the result of tectonic activity.