Detection of Adsorbed Water and Hydroxyl on the Moon

Abstract

Lunar Water: The Moon has been thought to be primarily anhydrous, although there has been some evidence for accumulated ice in permanently shadowed craters near its poles (see the Perspective by Lucey , published online 24 September). By analyzing recent infrared mapping by Chandrayaan-1 and Deep Impact, and reexamining Cassini data obtained during its early flyby of the Moon, Pieters et al. (p. 568 , published online 24 September), Sunshine et al. (p. 565 , published online 24 September), and Clark et al. (p. 562 , published online 24 September) reveal a noticeable absorption signal for H ₂ O and OH across much of the surface. Some variability in water abundance is seen over the course of the lunar day. The data imply that solar wind is depositing and/or somehow forming water and OH in minerals near the lunar surface, and that this trapped water is dynamic.