Jupiter's Moon Callisto
More details below:
Size & Distance
* Callisto is Jupiter’s second largest moon and the third largest moon in our solar system.
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* About the same size as Mercury.
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* circumference at its equator is about 9,410 miles.
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Jupiter's Moon Callisto
Geology
* Galileo spacecraft indicate Callisto may have a subsurface ocean and scientists estimate it may be 155 miles below the surface.
* Callisto’s interior may have layers of ice mixed with rock and metal, possibly extending to its center.
* Callisto’s rocky, icy surface is the oldest and most heavily cratered in our solar system.
* Looks like it’s sprinkled with bright white dots that scientists think are the peaks of the craters capped with water ice.
Atmosphere / Weather
* Scientists announced in 1999 that the Galileo spacecraft detected a very thin carbon dioxide exosphere—an extremely thin atmosphere—on Callisto during its observations in 1997.
* More recent research indicates Callisto also has oxygen and hydrogen in its exosphere.
Orbit & Rotation
* Callisto orbits about 1,170,000 miles from Jupiter and it takes about 17 Earth days for Callisto to complete one orbit of Jupiter.
* Callisto is tidally locked with Jupiter, which means that the same side of Callisto is always facing Jupiter.
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* It takes the Jovian system—Jupiter and all of its moons—about 12 Earth years to complete one orbit of the Sun.
