ISO* and cosmic water

Water, the basic substance essential for life, has been detected by the Inf rared Space observatory (ISO) in many places throughout the Universe, inclu ding our planetary neighbours in the Solar System, clouds circling or pouri ng out of stars, the vast spaces between stars, and distant galaxies, We sh ow here how these observations enable us to reconstruct the cosmic cycling of water, and its relevance to the presence of water on the Earth.