Comment »Posted on Friday 16 January 2009 at 5:20 pm by Jacob Aron
In Chemistry, Space & Astronomy

…but is there life on Mars? “Maybe” is the latest answer from NASA, with news that methane has been detected in the red planet’s atmosphere. The gas, which consists of four hydrogen atoms bonded to a carbon atom, could have biological or geologic origin according to NASA and university scientists.

The discovery of methane is significant, because many organisms here on Earth produce methane as by-product of digestion – cow flatulence being the famous example. We can’t say for sure the same thing is happening on Mars however, as methane can also be produced underground in a geological process that is similar to rusting. This could have happened in the past, when Mars was more volcanic, and it is only now that the methane is bubbling to the surface.

Something must be actively releasing methane though, because the gas is quickly destroyed in the Martian atmosphere. If it is indeed a form of microscopic life, it must be far enough below the planet’s surface to be insulated from the cold Martian air, as liquid water is necessary for all known forms of life to exist.

Dr. Michael Mumma of NASA’s Goddard Space Flight Center is the lead author of a paper in on the research which appeared in Science Express yesterday. He believes that organisms on Mars could be similar to those on Earth:

“On Earth, microorganisms thrive 2 to 3 kilometers (about 1.2 to 1.9 miles) beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen (H2) and oxygen. The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon.”

Unfortunately, it will be 2011 before we can get any further answers. It is hoped that NASA’s Mars Science Laboratory rover, due to launch in a couple of years, will be able to discover the origin of the Martian methane. By measuring the isotope ratios of the gas (isotopes are heavier versions of elements that are sometimes produced), the mission will be able to determine if life, which tends to use lighter isotopes, is the origin of the methane. I guess we’ll wait and see…


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