Data from NASA's Curiosity rover has revealed the martian environment lacks methane. This is a surprise to researchers because previous data reported by U.S. and international scientists indicated positive detections.link.
The roving laboratory performed extensive tests to search for traces of martian methane. Whether the martian atmosphere contains traces of the gas has been a question of high interest for years because methane could be a potential sign of life, although it also can be produced without biology.
"This important result will help direct our efforts to examine the possibility of life on Mars," said Michael Meyer, NASA's lead scientist for Mars exploration. "It reduces the probability of current methane-producing martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don't generate methane."
Curiosity analyzed samples of the martian atmosphere for methane six times from October 2012 through June and detected none. Given the sensitivity of the instrument used, the Tunable Laser Spectrometer, and not detecting the gas, scientists calculate the amount of methane in the martian atmosphere today must be no more than 1.3 parts per billion. That is about one-sixth as much as some earlier estimates. Details of the findings appear in the Thursday edition of Science Express.
"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," said the report's lead author, Chris Webster of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We measured repeatedly from martian spring to late summer, but with no detection of methane."