Jupiter has numerous moons, with the four largest being Io, Europa, Ganymede, and Callisto. These four, often referred to as the Galilean moons after their discoverer Galileo Galilei, are among the most fascinating objects in the solar system.

Io

Io is the most volcanically active world in the solar system. The intense geological activity is a result of tidal forces from Jupiter and the other Galilean moons, which cause the moon's interior to heat up.

Europa

Europa is primarily composed of silicate rock and has a water-ice crust. Evidence suggests that a saltwater ocean may exist beneath the ice, making it a prime candidate in the search for extraterrestrial life.

Ganymede

Ganymede is the largest moon in the solar system, even bigger than the planet Mercury and the dwarf planet Pluto. It is the only moon known to have its own magnetic field. The surface is a mix of bright, young terrain and dark, heavily cratered ancient terrain.

Callisto

Callisto is the most heavily cratered of the Galilean moons, indicating a lack of significant geological activity since its formation. It is composed of roughly equal amounts of rock and ice, and it is thought to have a subsurface ocean of salty water.

Key Characteristics of Galilean Moons

The table below summarizes some of the key distinguishing features of the four major moons of Jupiter.