Since landing at Galle Crater in 2012, the Curiosity Rover has been exploring the Martian surface under its wheels to learn more about the history of Mars. the planet. Curiosity also threw its nose into the air for a great snore to understand the Martian atmosphere.
So far, this snore has led to some discoveries that scientists are still trying to understand.
Earlier this year, a rover tuning laser spectrometer called SAM, which stands for Mars Analysis Sample, detected the largest amount of methane ever measured during its mission.
SAM also found that over time oxygen is behaved in a way that cannot be explained by anyone Currently, chemical process scientists understand.
SAM had enough time – about six years – to smell and analyze the atmospheric composition of Mars. The data reveal that 95% of the atmosphere at the surface is carbon dioxide, followed by 2.6% molecular nitrogen, 1.9% argon, 0.16% oxygen and 0.06% carbon monoxide.
Like Earth, Mars passes through its seasons; the air pressure changes over the course of a year. This happens when carbon dioxide freezes in the winter at the poles, resulting in a decrease in air pressure. It rises again in spring and summer, redistributing through Mars as carbon dioxide evaporates.
With respect to carbon monoxide, nitrogen and argon also follow similar dives and peaks. But oxygen didn't.
Surprisingly, oxygen actually increased by a peak of 30% in spring and summer, before falling back to normal in the fall.
Given the amount of time Curiosity monitors the atmosphere, he was able to find that this pattern was repeated, albeit with different amounts of oxygen.
Variation implies that oxygen is created by something, then subtracted.
"The first time we saw it was just mind-blowing," says Sushil Atreya, author of a study on a new book on oxygen levels and a professor of climate and space science at the University of Michigan.
The study was published on Tuesday. in Journal of Geophysical Research: Planets.  To eliminate errors, scientists checked to make sure SAM was working properly, but did not find any problems.
"We are struggling to explain this," says Melissa Trainer. study author and planetary scientist in NASA's Godard Space Flight Cen ter. "The fact that Oxygen does not repeat itself perfectly every season, it makes us think that this is not a problem with atmospheric dynamics, it must be some kind of chemical source and sink (of elements in the soil) that we still cannot account for. . "
This refers to the mystery of methane.
The June reading cites 21 parts per billion units of volume or ppbv. This means that the amount of air in Mars is estimated, one billion of the volume of air is methane.
So why is such an unusually large amount of methane so interesting? On Earth, microbial life is a key source of methane. But NASA also warned that life expectancies should be managed due to the fact that interactions between rocks and water can also produce methane, and Mars has water and plenty of rocks.
"With our current measurements, there is no way of telling whether the source of methane is biology or geology, or even ancient or modern," says SAM SAM Principal Paul Mahaffy of NASA's Goddard Space Flight Center in Greenbelt, Maryland.  This is not the first time methane has been discovered on Mars by Curiosity.In the course of its mission after landing in August 2012, Curiosity has repeatedly discovered methane and studies have been written on how gas levels actually rise and fall depending on the season.In summer it can reach up to 60%.
Can both be related to such chemistry as they fluctuate in the same way?
"We are beginning to see this excruciating correlation between methane and oxygen for the better part of the year of Mars." "Atreia said." I think there is something about it. I just don't have the answers yet. No one does. "
The origin of methane or oxygen will not be obvious, since the rover has no tools to track or determine the source. . While both oxygen and methane can be created from biological sources, they can also arise from chemistry, such as the interaction of water and rocks.
"We have not yet been able to come up with a process that produces the amount of oxygen we need, but we think it must be something in the soil surface that changes seasonally because there is not enough oxygen available in the atmosphere atoms to create the behavior we see, "says Timothy McConchy, a research co-author and assistant scientist at the University of Maryland.
Scientists wanted to share their findings with the hope that Martian experts could help determine what process created these increases.
"This is the first time we've seen this interesting behavior in a few years. We don't fully understand it, "Coach said. "To me, this is an open call to all smart people who are interested in this: See what you can think of."