There's Water on the Moon...
When the Apollo astronauts landed on the moon, they found its airless surface to be bone-dry. Now, 30 years later, a fleet of spacecraft have discovered traces of water there. But before you plan your trip to a lunar beach, bear in mind that the wet stuff exists as molecules embedded here and there in the regolith, the lunar equivalent of soil.
JPL's Moon Minerology Mapper (M3) on the Indian spacecraft Chandrayaan-1 found traces of water and hydroxyl, a molecule consisting of one oxygen atom and one hydrogen atom, in the top two millimeters of the regolith. M3 measured the sunlight reflected from the lunar surface and found that a wavelength of around three microns was being absorbed, the spectral signature of an O—H bond. The signal appeared all over, but was strongest near the poles.
Two other spacecraft confirmed the discovery, which was reported in the online edition of Science on September 24. Previously unpublished data from Cassini, which passed the moon in 1999 en route to Saturn, showed a similar signal. And comet hunter EPOXI, née Deep Impact, sealed the deal in a flyby in June with its high-resolution spectrometer.
Scientists aren't sure how much water there is, but models estimate that the abundance could be as much as 1,000 parts per million. In other words, wringing out one ton of the lunar surface would just fill your 32-ounce sipper bottle. —MW
