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Where does new water on Earth come from?
The basic constituents of water, oxygen and hydrogen, exist in stars as well as interstellar gas clouds. O and H love to get together and form H2
O, it's an exothermic reaction. So water is part of the primordial soup that planets are formed of. New water can accumulate on the earth due to accretion from meteors or comets. Rain, however, is not new water. It's just recycled from evaporation from oceans or lakes.
(published on 04/18/07)
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