According to NASA, scientists have previously hypothesised ionised hydrogen carried on solar winds from the Sun could be the source of the Moon’s water.
This should result in the amount of water on the Moon decreasing, every time it passes behind the Earth and is shielded from the Sun.
But this was not the case and, instead, NASA said water on the Moon builds up over time rather than “raining down directly from the solar wind”.
John Keller, NASA’s deputy project scientist at for LRO, said: “This result is an important step in advancing the water story on the Moon and is a result of years of accumulated data from the LRO mission.”