Water World
Water (Dihydrogen Oxide, H2O) is a truly remarkable chemical compound, fundamental to life on Earth . Earth is the only planet in the Solar System where the present surface temperature and pressure allow the three forms of water, solid (ice) , liquid (ocean) , and gas ( water vapor condensing in clouds ) to exist simultaneously . Water in one of these forms accounts for everything visible in this view of Earth from space looking north at the Bering Sea and the coast of Alaska , USA, around Bristol Bay.