Moons In Jupiter

What are its moons like?

Jupiter has 63 known moons. There are four major moons that were discovered by Galileo in 1610. Those moons are Io, Europa, Ganymede and Callisto. They are called the Galilean moons. There are often eclipses on Jupiter's cloud tops by the Galilean moons.
Amalthea GroupThere are four small moons orbiting inside Io's orbit. That group is called the Amalthea group because Amalthea is the largest one. They are all small and potato shaped. Amalthea is very red. The material of Jupiter's rings came from meteors knocking it off of those moons.

Io

Io is Jupiter's closest major moon. It is 3643.2 km across, slightly larger than Earth's Moon. It has volcanoes and molten sulfur lakes. There are not very many craters if there are any at all because the volcanic activity would cover them up. Io has an iron and maybe iron sulfide core at least 1800 km across. It is surrounded by a silicate shell. There is little water on Io. Maybe it was because when Jupiter was forming, it was hot enough to dry out Io, but not the other major moons. In Roman mythology Io was a beautiful young woman that Jupiter loved.

Europa

Europa is 3,121.6 km across, about ten percent smaller than Earth's Moon. It is made of silicates and has a layer of smooth water ice 10 to 30 km thick. The ice has long cracks in it and very few craters. It looks like the sea ice on Earth. The ice had slid around at the cracks. There is liquid water under the ice up to 100 km below the surface. There are also some large spots on the surface. In Roman mythology Europa was courted by Jupiter in the form of a bull.
Jupiter as seen by the space probe "Cassini". This is the most detailed color portrait of Jupiter ever assembled.

Ganymede

Ganymede is 5262.4 km across, making it 380 km wider than Mercury. It is Jupiter's largest moon and the largest moon in the Solar System. It had plate tectonics like Earth. There are older darker regions and newer areas with grooves where the plates moved. Newer craters have bright rays around them from material thrown up by impacts. Older craters look flat and faded because the icy surface does not hold the shape of the crater as well as rock does over long periods of time. Ganymede may have an iron and sulfur core with a silicate mantle and an icy shell. It may be like Io except with a layer of ice on it. In Roman mythology Ganymede was a beautiful young man who Jupiter kidnapped and made cupbearer to the gods on Mt. Olympus.

Callisto

Callisto is 4820.6 km across, about the same size as Mercury. It has many craters. Like craters on Ganymede, the older craters had faded. The largest crater is Valhalla. It has a bright center 600 km across with rings around it up to 3000 km across. Callisto is made of silicates and ice. There is a 200 km thick icy crust with a liquid water sea under it. In Roman mythology Callisto was turned into a bear by Jupiter's jealous wife Juno. Later Jupiter placed her in the stars as The Great Bear.
Other moonsThe other moons are tiny ones in several groups outside the orbits of the