Scientists have discovered that the most likely source of water on Moon is the constant stream of charged particles from the Sun known as the solar wind.
Findings by the University of Michigan imply that ice inside permanently shadowed polar craters on the Moon could contain
hydrogen atoms ultimately derived from the solar wind.
Theoretical models of lunar water stability suggest that hydrogen ions (protons) from the solar wind can combine with oxygen on the Moon’s surface to form water and hydroxyls, which consist of one atom of hydrogen and one of oxygen.
“Our work shows that the ‘water’ component, the hydroxyl, is widespread in lunar materials, although not in the form of ice or liquid water.