Why Are Methane and Oxygen Levels on Mars Fluctuating So Wildly in the Summer?
Methane and oxygen levels on Mars are fluctuating wildly, according to reports from BGR.
In a statement, NASA revealed that the Curiosity rover's Sample Analysis at Mars (SAM) miniature chemistry lab has been analyzing samples of Martian air in Gale Crater over a period of five years to determine the natural seasonal fluctuations in Mars' atmosphere.
Some of the measurements were expected – the Martian atmosphere is, on average, 95% carbon dioxide. The remaining 5% is a smattering of mostly nitrogen and argon, with a little oxygen and carbon monoxide.
In Martian winters, carbon dioxide freezes at the poles. This decreases the amount of carbon dioxide existing as a gas in the atmosphere – to the point that it actually lowers the air pressure on Mars' surface. Nitrogen and argon increase and decrease seasonally, depending on how much CO2 is in the air.
Scientists expected oxygen to behave the same way. It didn't. Oxygen levels on Mars actually increased 30% over the summer. By late autumn, oxygen levels had normalized... But the pattern has repeated itself every spring, "implying that something was producing it and then taking it away," the statement said.
Methane has been behaving rather curiously, too. There are normally trace amounts (0.00000004%) in Gale Crater. But in the summer, those levels spiked by 60%. Scientists initially thought it could be connected to whatever causes oxygen to increase so dramatically, but the two elements don't always rise and fall together. We still need to find more pieces to the puzzle.
"We're beginning to see this tantalizing correlation between methane and oxygen for a good part of the Mars year," Sushil Atreya – the paper's coauthor and a space and climate professor from the University of Michigan – said. "I think there's something to it. I just don't have the answers yet. Nobody does."
A study has been published in the Journal of Geophysical Research: Planets.