After analyzing the Martian atmosphere, NASA's Curiosity rover delivered a rather disappointing conclusion: there is no methane in this planet's atmosphere.
Since living organisms are the most important source of methane on Earth (about 90 is produced by them), some say that the lack of methane in this planet’s atmosphere is proof enough that there are no biological sources for it.
Still, Chris Webster, presently working with NASA's Jet Propulsion Laboratory in Pasadena, California, stated that, “The bottom line is that we have no detection of methane so far,” Scientific American reports.
Furthermore, “But we're going to keep looking in the months ahead since Mars, as we all know, may yet hold surprises for us.”
For the time being, scientists will have to settle for explaining previous methane detections on Mars by referring to non-biological sources such as comet strikes and interplanetary dust motes.