The Way of the Water
The water that fills the earth's oceans, lakes and rivers has come a long way. It is initially formed in molecular clouds, which consist of 90 percent molecular hydrogen. When individual regions in these clouds condense into stars, it plays an important role in the formation of the protoplanetary disk. In the process, it is often transported as ice to their outer regions, from where it is later carried by comets to the inner planets. Cosmologists have already been able to document the first and the last section of this path well, but they have had measurement problems with…
