Is science sometimes in danger of getting tunnel vision? Recently published ebook author, Ian Miller, looks at other possible theories arising from data that we think we understand. Can looking problems in a different light give scientists a different perspective?

Planetary Formation Update – October

The  first round of results came in from Curiosity at Gale crater, and I found the results to be both comforting but also disappointing. The composition of the rocks, with one exception, and the composition of the dust were very similar to what had been found elsewhere on Mars. We now know the results are more general, but they are not exactly exciting. Dust was heated to 835 oC and a range of volatiles came off, and there was, once again, evidence of some carbonaceous matter, but the products obtained (SO2, CO2, and O2, HCN, H2S, methyl chloride, dichloromethane, chloroform, acetone, acetonitrile, benzene, toluene and a number of others) were almost certainly pyrolysis products.
 
An interesting paper (Nature Geosci. doi:10.1038/ngeo1930) found that when ices similar to those in comets were subjected to high velocity impacts, several aminoacids were produced. However, some were aminoacids such as α-aminoisobutyric acid and isovaline, which are not used for protein, and the question is, why not? One reason may be that our aminoacid resource did not come from such comets.
 
A circumstellar disk was identified around a white dwarf, and the disk was considered to have arisen from a rocky minor planet (Science 342: 218 – 220). There was an excess of oxygen present compared with the metals and silicates, and a lack of carbon, and this is consistent with the parent body having comprised 26% water by mass. This was interpreted as confirming that water-bearing planetesimals exist around A and F-type stars that end their lives as white dwarfs. Of particular interest was the lack of carbon. What sort of body could it have come from? I have seen suggestions that it would be a body like Ceres, in which case my proposed mechanism for the formation of minor planets would not be correct (because of the lack of carbon) but another option might be something that accreted in the Jovian zone, where I argue carbon is not accreted significantly.
 
Finally, Curiosity made a specific search for methane in the Martian atmosphere and put an upper limit of 1.3 ppbv, which suggests that methane seen on Mars did not come from methanogenic microbial activity, but rather from either extraplanetary or geologic sources. The latter fits nicely with my proposed mechanism of formation of Mars.
Posted by Ian Miller on Nov 4, 2013 1:35 AM Europe/London

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