Thursday, September 24, 2009

The why and where of water on the Moon

Arlin P.S. Crotts
Department of Astronomy, Columbia University
Columbia Astrophysics Laboratory,
Informal to the Lunar-L Group
I am not sure why so few investigators have paid attention to these results, but if you would like to see an analysis of the situation regarding lunar water that takes these and the rest of the evidence into fair consideration, please refer to my paper (originally submitted June 2007, resubmitted September 2, 2009)

"Lunar Outgassing, Transient Phenomena & the Return to the Moon II: Predictions and Tests for Outgassing/Regolith Interactions," Crotts & Hummels (2009), Astrophysical Journal, submitted

If you look at the current evidence, it indicates that the water content is higher at greater depths, and may not be fundamentally a surface effect. (Please refer to the Akhmanova et al. 1978 paper: "Water in the regolith of Mare Crisium Luna-24," Akhmanova, Dement'yev & Markov (1978) Geokhimiya, 2, 285).

IR diffuse reflection and IR transmission studies of lunar soil samples obtained by Luna-24 are described. Approximately 0.1 wt% water was detected in samples from a depth of 143 cm, and the amount of water seemed to increase with depth, although the extent of change was almost at the limit of technique sensitivity. The possibility of sample contamination by water is considered.

Water was not detected in samples obtained during earlier moon missions when a similar procedure was applied, but in the earlier studies the lower limit of detection was approximately 0.2 wt% water. The significance of the detection of water for theories of lunar development is indicated.

There are a number of ways to approach this problem, and I have papers coming out based on further data, but I will not tip my hand about these at this time.

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