Not so hostile: The Moon may be wetter than we thought.
Credit: NASA/Lick Observatory
According to their calculation, the Moon's pre-eruption magma may have contained up to 750 ppm, similar to the water content of primitive magma that once erupted on the mid-ocean ridges on Earth's sea floor.
Lacking an atmosphere, the Moon lost almost all of this water when the molten rock spewed onto the surface and cooled. As much as 95 per cent of the vapour drifted out to space and was lost forever.
But – so goes the theory – the rest may have drifted towards the cold poles of the Moon, where it may remain as ice in deep, permanently shadowed craters.
Fanciful notion
The notion of ice at the lunar poles was once dismissed as fanciful, but it has gained credibility in recent years, backed by data sent back in 1994 by a U.S. orbiter, Clementine.
Seeking to find out more, NASA is to send a scout, the Lunar Reconnaissance Orbiter, with a launch date of no earlier than November 24 this year, followed by another craft, the Lunar Crater Observation and Sensing Satellite, in 2009.
Finding water would be a boon, and not just for the tantalising perspective that it would open into Moon's past. It could conceivably be tapped for a manned outpost, thus drastically cutting the cost of a permanent return to the Moon.
