If we wanted to establish a colony on the Moon, most people assumed we were going to have to take water there, or at least make it ourselves through chemical reactions. More recently, however, this has come into question. Without a protective atmosphere, water ice on the Moon’s surface would turn to gas when sunlight hit it, and quickly be lost to the Moon’s weak gravity.
Consequently, Dr Shuai Li of the Hawaii Institute of Geophysics and Planetology looked at the bottom of craters near the lunar north and south poles – the only places direct sunlight never reaches. Unfortunately, these spaces, called cold traps, are also the hardest parts of the Moon to study – not least because they are in permanent shadow.
Whether the ice came from within the Moon, or was delivered by comets, remains unclear.