This could be it, folks. The evidence for life on Mars is mounting—it’s still circumstantial at this point, but every new discovery and every tantalizing hint gets us closer to answering the million (billion?) dollar question: did life ever exist on Mars? And the obvious follow up question: does life exist on Mars right now? In addition to the evidence released last week about Gale Crater’s massive lake and the amount of time they now believe Mars was ripe for life, scientists released another new finding involving surprising and fluctuating methane emissions on the Red Planet. Sure, there are a few possible explanations for the methane, but one of them is that it comes from something biological—i.e., Martians. Probably only microbial ones, but still. This is a seriously big deal.
As you might know, Curiosity Rover’s time on Mars has culminated in its journey to Mount Sharp, where it’s been examining rocks and soil buried deep below the mountain’s surface. Mount Sharp is located in Gale Crater, which scientists now know used to have a bunch of lakes, rivers, and deltas, and seems like a pretty good spot to foster some kind of life. But life is tough to find, especially when you’re not exactly sure what you’re looking for. Martian meteorites have been found to contain organic compounds, but scientists still can’t say with certainty that they prove the existence of past life on Mars. So Curiosity keeps looking. One of the best ways scientists know of to hunt for life is by studying methane emissions (one of the gases responsible for the greenhouse effect).