A Whiff of Water Found on the Moon – ScienceNOW

A Whiff of Water Found on the Moon

By Richard A. Kerr    ScienceNOW Daily News

24 September 2009

Yes, the moon is a “wetter” place than the Apollo astronauts ever could have imagined, but don’t break out the beach gear just yet. Although three independent groups today announced the detection of water on the lunar surface, their find is at most a part per 1000 water in the outermost millimeter or two of still very dry lunar rock…

The discovery “opens up a whole different avenue to a source of water on the moon,” says M³ principal investigator Carlé Pieters of Brown University. EPOXI observations show the water/hydroxyl signal coming and going from the surface over days, notes Pieters, which shows that there’s water loosely bound to surface rock, not just tightly bound hydroxyl. The best estimate coming out of the reported observations for water’s abundance is 0.2 to 1 part per 1000 of water, she says, and that’s in the upper millimeter or two that spectroscopy can penetrate. At those levels, an astronaut would have to process the soil from a baseball-diamond-size plot to get a decent drink of water.

More tantalizing, the water becomes more abundant closer to the poles. That and water’s abundance varying with time suggests to Pieters that water is being produced on the moon–perhaps through solar wind hydrogen interacting with surface rock–and then hopscotching from place to place through the moon’s vanishingly thin atmosphere. Because a water molecule would stick more securely to colder rock, water would tend to migrate toward the colder polar regions. There, it might become trapped for eons as subsurface ice in permanently shadowed craters, which are currently thought to be among the coldest places in the solar system…

via A Whiff of Water Found on the Moon — Kerr 2009 (924): 1 — ScienceNOW.