We take for granted a lot of gases here on Earth, including our precious oxygen. Even less so gases like methane, which is mostly a waste product of certain living organisms. But when you find unusually high levels of that substances in a planet bereft of life but believed to have once hosted life, it’s a pretty big deal. That’s the reason why scientists at NASA were more than happy to spend their weekend at work to analyze and do more tests with the data that the Curiosity Rover just sent them from Mars.
NASA reported that Curiosity just found the largest amount of methane gas ever measured on the red planet. It’s not an entirely gigantic amount by earth standards, only “21 parts per billion units by volume” or ppbv. In practical terms, NASA explains it as one billionth part of a volume of Martian air sample will be methane.
The source of methane can be one of two things. It could simply be the by-product of interactions between rock and water, and Mars does have water, contrary to popular misconception. The more exciting possibility, however, is that the amount of methane is being released by microbial life on Mars as it does on Earth.
While modern-day Martians have mostly been debunked, scientists do believe that the planet may have, at one point, supported organic life as we know it. There is a possibility that some of that life may have survived and retreated deep into the ground. No, not aliens but microbes. Though you could probably consider them alien microbes, too.
Of course, there might be other possibilities, like this volume of methane being trapped underground for years and only surfacing now. Or it could just be rocks and water interacting. Either way, finding the true source of that much methane was exciting enough for the scientists to spend their weekend going over the data and performing further tests.