Saturn’s “Death Star”-like moon Mimas may have a boiling ocean under its icy shell. The moon pitted with craters—including a very large one, giving it its nickname—may appear to be geologically dead, ...

Far from the warmth of the Sun, some of the coldest-looking worlds in the solar system may be hiding the hottest surprises. New modeling work suggests that several icy moons of Saturn and Uranus could ...