NASA Briefs Preliminary Plume Findings from Moon Mission |
NASA Briefs Preliminary Plume Findings from Moon Mission |
Nov 10 2009, 09:26 PM
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Member Group: Members Posts: 239 Joined: 18-December 07 From: New York Member No.: 3982 |
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Nov 14 2009, 09:52 PM
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Member Group: Members Posts: 293 Joined: 22-September 08 From: Spain Member No.: 4350 |
But you are using estimates for pure, solid ice and a solid surface. Colaprete said that looking at the size of the crater that seemed unlikely.
Those 100kg minimum of H20 probably meant more than 0.1 cubic meters, and the average density of the ejected material could have been less than lunar rock. Organics like methane yield water easily, their mass should count too. |
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Nov 15 2009, 04:39 AM
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Newbie Group: Members Posts: 6 Joined: 17-September 09 Member No.: 4945 |
But you are using estimates for pure, solid ice and a solid surface. Colaprete said that looking at the size of the crater that seemed unlikely. Those 100kg minimum of H20 probably meant more than 0.1 cubic meters, and the average density of the ejected material could have been less than lunar rock. Organics like methane yield water easily, their mass should count too. The 100 kg reported was based on a column abundance (# per-square-meter), derived from the H2O band depths in the near-infrared spectra. This represents water molecules only. However, this number is derived from a model fit to the data, so uncertainties are large, as is typical for remote sensing spectroscopy. Regardless, the order of magnitude result will likely stand up, meaning the uppermost layers of the cold traps are about as "wet" as predicted (c.f. Campbell et al, Nature, 2006; Siegler et al, LPSC, 2009). That is, it's pretty dry, but not hopeless. Also, don't forget that we're only sampling the uppermost ~1-5 meters (including the ground-based radar results), so there could still be slabs of ice below. Perhaps even more interesting are some of the other compounds, including several organic volatiles, that were observed in the ejecta plume. An interesting take on the smorgasbord of volatiles likely to accumulate at the lunar polar cold traps, is provided by Zhang and Paige, "Cold-trapped organic compounds at the poles of the Moon and Mercury: Implications for origins" Geophysical Research Letters 36, L16203. |
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