Icy moon

Icy moons are a class of natural satellites with surfaces composed mostly of ice. An icy moon may harbor an ocean underneath the surface, and possibly include a rocky core of silicate or metallic rocks. It is thought that they may be composed of ice II or other polymorph of water ice.^[1] The prime example of this class of object is Europa.

Icy moons warmed by tides may be the most common type of object to have liquid water,^{[citation needed]} and thus the type of object to possibly have water-based life.

Some icy moons exhibit cryovolcanism, as well as geysers. The best studied example is Saturn's Enceladus.