For a planet at the center of so many discussions about life, Mars can seem like a really dead world.
It’s cold, dry, and dusty with a thin atmosphere that doesn’t block out much solar radiation. There’s minerals and gullies that suggest water flowed there more than three billion years ago, but aside from a few wandering robots, a big landslide, and the occasional planet-wide dust storm, modern Mars doesn’t seem to see a lot of action.
Or maybe we just haven’t been looking in the right places.
Today a group of university and NASA scientists announced they’ve found plumes of methane that could be coming from some mysterious underground source on Mars’s northern hemisphere.
—Image courtesy NASA
Over a three-year span starting in 2003, ground-based observatories saw that the plumes appeared and disappeared, varying with the seasons. At one point Mars spewed out about 19,000 metric tons of methane at nearly 0.6 kilograms a second. Take that, Aussie sheep.
And so comes the big question: Does active methane mean life in motion?
On Earth close to 90 percent of our methane is produced by biology, including some microbes that live in deep, dark places similar to what we think subterranean bodies of water would be like on Mars.
In typical sciencey fashion, the answer is: It depends. Sure, underground microbes could be creating methane, or they could be feeding on it.
But you can also sometimes get methane when water reacts with hot rocks. Or it could be ancient frozen methane that’s only now being exposed to the air by weathering or subtle geologic motions.
Stripes of liquid water react with magma inside a Martian hill, which then vents methane
—Image courtesy NASA/Susan Twardy
Still, it’s a good bet NASA is excited by the prospect, considering the astrobiology folks who were asked to join the panel at today’s news briefing.
Lisa Pratt of Indiana University was respectfully cautious, but did start talking toward the end of the event about how, of the two likely sources of recently made methane, life is actually a slightly better candidate—the circumstances that cause geology to make methane are actually rare, on Earth at least.
She did note, however, that if anything is burping its way along underneath the Martian surface, we’d be talking several meters to a few kilometers underground, far deeper than anything we’re sending to Mars anytime soon could drill.
The issue then becomes, are we convinced enough to build and launch missions designed to do that sort of heavy lifting.
According to lead study author Michael Mumma, of NASA’s Goddard Space Flight Center, it took us so long to even find the methane because nothing we’ve got in orbit was properly equipped to see such gases in the atmosphere, much less watch them over time.
Finding Martian microbes would certainly be the headline of the century, although it also fits well into the “now what?” department. What happens when we find life on another planet? Will the seas boil and the moon go dark and the dead start rising from the grave?
I just hope that by the time we do confirm or deny life on Mars, I’m still alive to write about it!