JUPITER'S MOONS and RINGS

Jupiter has 63 moons varying from captured asteroids a few kilometres across to objects the size of small planets. Ganymede is larger than the planet Mercury.

Jupiter has a system of rings but unlike the rings of Saturn they are thin and were not discovered until spacecraft got close to Jupiter.

Jupiter's moons can be roughly divided into a number of different categories depending on size and type of orbit. The inner satellites move in roughly circular orbits and were probably formed at the same time as Jupiter. The outer satellites move in elliptical orbits, some even orbit in the opposite direction to the majority of the other moons. These moons are probably asteroids that came too close to Jupiter and were captured by its gravitational field.

The four largest moons are Io, Europa, Ganymede and Callisto. These are called the Galilean moons as they were discovered by Galileo when he turned a telescope on Jupiter for the first time in 1610. These can be seen as four bright stars around Jupiter through a small telescope or binoculars.

Listing and details of Jupiter's moons here

More information on inner satellites here

More information on outer satellites here

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