While the crater-pitted moon may appear geologically dead, researchers have discovered more could be going on under its icy ...

But on larger icy moons, the ice layer may break up before the water boils, preventing the formation of a boiling ocean.

Saturn's small moon Mimas, nicknamed the "Death Star" for its giant crater, may have a hidden ocean beneath its icy shell, researchers from UC Davis said. A slight wobble in the moon's movement ...