Curiosity Takes A Look At Martian Dirt

Hints that NASA’s Curiosity rover may have found organic compounds on Mars were clarified last week. At a Dec. 3 press conference, NASA scientists revealed that chlorinated methanes—CH₃Cl, CH₂Cl₂, and CHCl₃—have been detected in a sandy soil sample processed by Curiosity’s onboard chemistry laboratory. The findings were presented at the American Geophysical Union meeting in San Francisco. But whether those organic compounds can be taken as a sign that Mars once harbored life is not yet clear: The compounds’ chlorine has been confirmed to be martian, but team members will need to perform more analyses to determine whether the carbon source is also from Mars. Even if scientists eventually show that the carbon is martian in origin, they’ll have to carefully analyze carbon isotopes and gather additional samples before concluding whether the organics are abiotic or biological in origin. That will take time, said the mission’s project scientist, John P. Grotzinger. “We’re doing science at the speed of science, in a world that runs at the pace of Instagrams.”