Mars Looks More Hostile to Life
The methane Mars produces gets destroyed rapidly. This is leading some planetary scientists to get depressed about the possibility of finding life there.
The BBC News, Space.com and New Scientist all reported on the paper in Nature,1 saying this represents bad news for life. In models by Franck Lefevre and Francois Forget, patterns of methane distribution can only be explained if the atmospheric methane is destroyed within an hour of release – 600 times faster than on earth. Any process able to do that to the simplest organic molecule would most likely be highly deleterious to life. As the BBC put it, whatever process is responsible for the destruction may be wiping out other organic molecules, which are necessary for life as we know it.” Humans may have second thoughts about going there (see 07/26/2009, bullet 1). These risks to humans from poison atmosphere and toxic dust, though, are not stopping reporters from speculating that the source of the methane may be living organisms. When geology can produce methane without as much speculation, Ockham’s Razor would prefer the latter.
The actual timescales for methane production and destruction are uncertain enough to require better in situ measurements by future orbiters and rovers. The Mars Science Laboratory may be able to nail down better numbers in 2012.
Meanwhile, ammonia is showing up at a couple of Saturn’s moons. Science News said that signatures of ammonia were found in the Enceladus geysers. And Space.com reported signatures of ammonia at Titan. By decreasing the melting point of water, ammonia indicates the possibility of cryovolcanism and underground reservoirs of liquid water. This means a prerequisite for hyped speculation about life has been met. “The presence of ammonia and hydrocarbons could have interesting implications for the possibility of life existing on Titan,” said Space.com, and Science Daily quoted a scientist asking, “Where liquid water and organics exist, is there life?” Such optimism seems premature when the prime location in the search for life, Mars, is looking pretty grim.
1. Lefevre and Forget, “Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics,” Nature 460, 720-723 (6 August 2009) | doi:10.1038/nature08228.
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