Filled with briny lakes, the Quisquiro salt flat in South America's Altiplano region represents the kind of landscape that scientists think may have existed in Gale Crater on Mars, which NASA's Curiosity Rover is exploring. Credit: Maksym Bocharov
Topics: Astrobiology, Astrophysics, Atmospheric Science, Mars, NASA, Planetary Science
The most surprising revelation from NASA's Curiosity Mars Rover—that methane is seeping from the surface of Gale Crater—has scientists scratching their heads.
Living creatures produce most of the methane on Earth. But scientists haven't found convincing signs of current or ancient life on Mars, and thus didn't expect to find methane there. Yet, the portable chemistry lab aboard Curiosity, known as SAM, or Sample Analysis at Mars, has continually sniffed out traces of the gas near the surface of Gale Crater, the only place on the surface of Mars where methane has been detected thus far. Its likely source, scientists assume, are geological mechanisms that involve water and rocks deep underground.
If that were the whole story, things would be easy. However, SAM has found that methane behaves in unexpected ways in Gale Crater. It appears at night and disappears during the day. It fluctuates seasonally and sometimes spikes to levels 40 times higher than usual. Surprisingly, the methane also isn't accumulating in the atmosphere: ESA's (the European Space Agency) ExoMars Trace Gas Orbiter, sent to Mars specifically to study the gas in the atmosphere, has detected no methane.
Why is methane seeping on Mars? NASA scientists have new ideas, Lonnie Shekhtman, NASA, Phys.org.
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