Here's a couple of pictures of the craft that will find strong evidence for life on Mars. I hope.
One of the things I have never understood is the view that there probably isn’t life on Mars. Surely, in the age of extremophile bacteria, it would be odd if there weren’t something there beneath the arid surface?
A couple of new results strengthen my conviction. First up a paper in Science that reports the discovery of organisms that live independently of the sun. Instead, they get their energy from natural radioactivity in the basalt rocks where they live. The organisms live 3 to 4 km down a South African gold mine, in water trapped in a crack.
The radioactive uranium in the rocks breaks up water molecules to produce hydrogen gas. The microbes use this to turn sulphate molecules, also in the rock, into hydrogen sulphide – basically a mimic of photosynthesis, but powered by radioactivity not sunlight. Read more about it here. It’s enough to make you think that life is a cosmic imperative, as Christian de Duve once suggested. Wherever there is chemistry and the release of nuclear energy (which is everywhere), something conspires to create that process we call life. Maybe it’s just the laws of physics at work.
All of which makes it even more exciting that NASA are now thinking of searching for biologically-generated methane again, more than 30 years after Gilbert Levin did it for the Viking mission. In 13 Things I’ve written about his results: positive, but, essentially, shouted down by the (false) negative of another experiment. When the Mars Science Laboratory launches next year (that's the aeroshell in the picture), it might finally vindicate his claims.
There is new evidence that methane is being given off in “hotspots” on Mars. Methane is often (not always) a result of biological processes, such as microbial processing of nutrients. This is what Levin claimed to see in 1976.
A Nature News story says methane clouds spanning hundreds of kilometres form over these hotspots. It seems to be created at an astonishingly fast rate, indicating the possible presence of methane-generating bacteria.
One of the hotspots was on the longlist of landing sites for the MSL lander, but didn’t make the shortlist. That decision is now being revisited. Since MSL can detect the ratio of carbon isotopes in methane, that might give good indication of a biological origin for the gas. Terrestrial biology produces more carbon-12 than any other isotope: if the Martian methane is rich in carbon-12, it’s a strong suggestion that Gil Levin was right all along.
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