MSL - SAM and CHEMIN, Discussion of the science/results from these instruments |
MSL - SAM and CHEMIN, Discussion of the science/results from these instruments |
Nov 21 2012, 11:46 AM
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Senior Member Group: Admin Posts: 3108 Joined: 21-December 05 From: Canberra, Australia Member No.: 615 |
ADMIN NOTE: Hi All, a new topic for the discussion of the science from the SAM and Chemin instruments.
There has been a very important amendment to Rule 1.3 which is explained here. Please remember Rule 1.3 at all times when discussing matters in this section. |
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Dec 3 2012, 07:14 PM
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Junior Member Group: Members Posts: 98 Joined: 24-November 04 Member No.: 111 |
The chlorinated methanes are interesting. CH3Cl, CH2Cl2, and CHCl3 were detected.
If the starting C-containing material was CO2, somehow the C would have to be reduced, and a source of H would also be needed (from the decomposition of water, presumably?). It is not a simple process to reduce the C in CO2. However, i want to point out that some metal oxide dusts can function as capable catalysts for CO2 reduction (this is an active area of chemical research!). For example a potential heat assisted catalytic cycle using a metal oxide, (unbalanced reaction): H2O + CO2 + MOn + heat --> H2 + CH4 + CO + MOn+2 MOn+2 + heat --> MOn + O2 The CH4 is then subject to free radical chlorination, from a perchlorate origin. Did the press conference presentation say whether they also detected CH4 or CO ? If my above mechanism is correct, then CH4 should have been found too, probably in greater amounts than the CH3Cl. If not, why not? I doubt that CH4 was not present if the chlorinated methanes were seen. I do note that they did detect O2. Of course the O2 could have come from the perchlorate, or my mechanism, or both. Someone needs to do a careful mass balance ! I may need to work out an alternate pathway using a sulfur compound as my reducing agent. The link does say that sufides may have been involved, these can be oxidized to SO2. H2S and SO2 were detected. NASA release Now I can understand why Grotzinger got excited: Perhaps he at first thought he had a biogenic source of CH4. But abiogenic sourced CH4 is much more likely, in my opinion, perhaps via a reaction pathway similar to this outline. |
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