Water on terrestrial planets of the Solar System is only 2.1×10, a factor of 8 lower than Earth's VSMOW ratio. It is unclear how such a difference could exist, if physisorption were indeed the dominant form of HO accretion for Earth in particular and the terrestrial planets in general. Water on terrestrial planets of the Solar System The origin and development of water on terrestrial planets, Venus, Earth, Mars, and the closely related Earth's Moon, varies with each planetary body, with the exact origins remaining unclear. Additionally, the terrestrial dwarf planet, Ceres is known to have water ice on its surface. A significant amount of surface hydrogen has
Uranus water, ammonia, and methane, along with traces of other hydrocarbons. It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of , and has a complex, layered cloud structure with water thought to make up the lowest clouds and methane the uppermost layer of clouds. The interior of Uranus is mainly composed of ices and rock. Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The Uranian system has a unique configuration because its axis of rotation is tilted sideways, nearly into the plane of its solar orbit. Its north