Surface features of Uranus' icy moon Miranda point to the existence of a once deep ocean, one that still may exist today.

For decades. researchers have theorized that resting beneath Callisto's pockmarked surface is a liquid saltwater ocean that spans the entire moon. After taking a closer look at data from 30 years ...

Callisto, Jupiter's second-largest moon, may have a rocky surface with an ocean beneath the surface. If there was a contest for the most interesting moon in our solar system, Callisto would be a ...