The Mars rover has delivered what a NASA scientist calls an "oh my gosh moment"—it detected methane on the red planet, reports the New York Times. The discovery is making headlines because the gas had to originate somewhere, and one possibility is that the source is some form of microbial life, reports the Guardian. “That we detect methane in the atmosphere on Mars is not an argument that we have found evidence of life on Mars, but it’s one of the few hypotheses that we can propose that we must consider,” says scientist John Grotzinger of the Curiosity team. The rover picked up spikes in the levels of methane that disappeared in a matter of weeks.
The source, however, could be geological rather than biological, explains National Geographic: "Interactions between water and rock could produce methane, as could sunlight cooking off meteorite debris on the Martian surface." It's also possible that even if microbes did create the methane, the bugs are long gone, reports the BBC. The gas could have been trapped underground eons ago, and it surfaces periodically because of thermal disturbances. The best hope for real answers is if Curiosity happens to detect a large amount of the gas that can be properly analyzed. Today's news is all the more surprising because NASA announced just last year that the rover could find no methane at all. (Read more methane stories.)