Cryovolcano

A cryovolcano (colloquially known as an ice volcano) is a theoretical type of volcano that erupts volatiles such as water, ammonia or methane, instead of molten rock. Collectively referred to as cryomagma or ice-volcanic melt, these substances are usually liquids and can form plumes, but can also be in vapour form. After eruption, cryomagma is expected to condense to a solid form when exposed to the very low surrounding temperature. Cryovolcanoes may potentially form on icy moons and other objects with abundant water past the Solar System's snow line (such as Pluto). A number of features have been identified as possible cryovolcanoes on Pluto, Titan and Ceres. In addition, although they are not known to form volcanoes, ice geysers have been observed on Enceladus and potentially Triton.

One potential energy source on some solar system bodies for melting ices and producing cryovolcanoes is tidal friction. It has also been suggested that translucent deposits of frozen materials could create a subsurface greenhouse effect that would accumulate the required heat.

Signs of past warming of the Kuiper belt object Quaoar have led scientists to speculate that it exhibited cryovolcanism in the past. Radioactive decay could provide the energy necessary for such activity, as cryovolcanoes can emit water mixed with ammonia, which would melt at 180 K (−95 °C) and create an extremely cold liquid that would flow out of the volcano.

On November 27, 2005, Cassini photographed geysers on the south pole of Enceladus. (See also: Enceladus (Cryovolcanism).)

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