Cloud - Extraterrestrial

Extraterrestrial

Within our Solar System, any planet or moon with an atmosphere also has clouds. Venus's thick clouds are composed of sulfur dioxide. Mars has high, thin clouds of water ice. Both Jupiter and Saturn have an outer cloud deck composed of ammonia clouds, an intermediate deck of ammonium hydrosulfide clouds and an inner deck of water clouds. Saturn's moon Titan has clouds believed to be composed largely of methane. The Cassini–Huygens Saturn mission uncovered evidence of a fluid cycle on Titan, including lakes near the poles and fluvial channels on the surface of the moon. Uranus and Neptune have cloudy atmospheres dominated by water vapor and methane gas.