We think of the Moon as a dry and dusty sort of place, but over the years, scientists have learnt that Earth’s satellite is actually rather loaded with water – in volcanic deposits, in its chilly poles, in the permanent shadows of its craters.
But it looks like water has also been hiding somewhere else, in significant abundance: the lunar subsoil, mere inches from the Moon’s surface.
We had hints it was there. Cassini detected trace amounts of it on its 1999 flyby. NASA probe Deep Impact detected it on a 2009 flyby, as did Indian lunar probe Chandrayaan-1. But the source of this water was unknown – scientists thought it had been deposited there, perhaps by the solar wind or passing meteoroids. Read more