If there was a contest for the most interesting moon in our solar system, Callisto would be a contender. Jupiter's second-largest moon has more impact craters on its surface than any other ...

New evidence from an old NASA mission supports the theory that Jupiter's moon Callisto is in fact an ocean world.

The results strongly suggest that Callisto could have an ocean cased in ice sitting above its rocky core. The spacecraft discovered something strange about this moon: it appeared to react to ...

And there are tantalizing hints that oceans could exist on Ganymede, Callisto ... or an oddly shaped core. But an ocean seemed impossible. Mimas looks much like our Moon, with a heavily cratered ...

and Callisto. The Moon is non-luminous, meaning that it does not produce light. We see the Moon because it reflects light from the Sun, and half of the Moon’s surface is always illuminated.