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
Exploration of Uranus cloud tops. This was the probe's first solo planetary flyby, since "Voyager 1" ended its tour of the outer planets at Saturn's moon Titan. Uranus is the third-largest planet in the Solar System. It orbits the Sun at a distance of about and completes one orbit every 84 years. The length of a day on Uranus as measured by "Voyager 2" is 17 hours and 14 minutes. Uranus is distinguished by the fact that it is tipped on its side. Its unusual position is thought to be the result of a collision with a planet-sized body early in the Solar