Facts about Jupiter's moon Callisto, the third largest moon in the Solar System and the most heavily-cratered object.
The Solar System is the name given to the part of space that surrounds the Sun. Even though it is bigger than anything we can imagine, the Solar System is actually a very tiny part of the universe.
Discover 100 Space Facts That Will Leave You Speechless! Explore mind-bending realities from our solar system to distant ...