Curiosity Confirms Organics On Mars

NASA’s Mars rover Curiosity has discovered that organic compounds are present in the soil of the Red Planet, scientists announced on Dec. 16 at the American Geophysical Union meeting in San Francisco. Curiosity also recently detected a localized but dramatic surge of methane of unknown origin in the martian atmosphere (Science 2014, DOI: 10.1126/science.1261713). Organic compounds, particularly methane, are generally produced by living organisms, although these compounds can be synthesized by abiotic reactions of soil, water, and solar radiation. Right now, scientists say they have no way of determining their source on Mars. But the rover did detect the presence of chlorobenzene, dichloroethane, dichloropropane, and dichlorobutane. The molecules are likely the products of precursor organics and formed during heating of the perchlorate-rich martian soil. Methane plumes have been detected on Mars previously, but the new measurements are the first from a craft on the martian surface. Over a period of 20 months, Curiosity recorded background atmospheric levels of methane of about 0.7 ppb. But then suddenly methane levels climbed to 9 ppb over several months. Scientists suggest the gas is periodically escaping from clathrates beneath the ground.