Eruption of water or other liquid or vapor-phase volatiles (collectively referred to as “cryomagma”), together with gas-driven solid fragments, onto the surface of a planet or moon due to internal heating. After eruption cryomagma condenses to a solid form when exposed to the very low surrounding temperature. Cryovolcanism is not known to exist on Earth. Ice volcanoes were first observed on Neptune’s moon Triton during the Voyager 2 flyby. Indirect evidence of cryovolcanic activity has since been observed on several other icy moons of our solar system, including Europa, Ganymede, and Enceladus. The Cassini-Huygens mission has found a methane-spewing cryovolcano on Titan, and such volcanism is now believed to be a significant source of the methane found in Titan’s atmosphere.

Some or all content above used with permission from J. H. Wittke.