The possibility of liquid water beneath the surface of Saturn’s moon Mimas may offer clues to how such seas form, and another spot to search for life

The outer solar system is awash with liquid water. A briny ocean is concealed beneath the icy crust of Jupiter’s fourth largest moon, Europa — with more water than all of Earth’s oceans combined. A subsurface sea on Saturn’s moon Enceladus spews plumes of water vapor into space. And there are tantalizing hints that oceans could exist on Ganymede, Callisto, Titan and other distant moons, too.

Now another moon appears to be secretly flooded. Saturn’s moon Mimas, known for its uncanny resemblance to the Star Wars Death Star, might harbor liquid water beneath its icy shell. If true, similar seas could be hiding in plain sight, and the outer solar system may be far more habitable than previously thought.