Mysterious Oxygen Spike Seen on Mars Puzzles Scientists

• Mysterious Oxygen Spike Seen on Mars Puzzles Scientists
  by MICHAEL GRESHKO, https://www.nationalgeographic.com/, 18 Nov 2019
  The discovery showcases some of the chemical enigmas we need to untangle for future Mars missions to properly search for life.
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  AFTER MORE THAN six years sniffing the red planet’s thin, frigid air, a NASA rover has made a startling discovery: There’s more oxygen gas in the Martian atmosphere than scientists expected, and what’s there is behaving strangely.
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  In the Martian spring and summer, the red planet’s oxygen levels spike an extra 400 parts per million, or 30 percent above what researchers expected to see based on the behavior of other gases in the planet’s atmosphere. The oxygen spike seems to partially correlate to another gassy mystery: a seasonal ebb and flow of atmospheric methane on Mars. (Find out more about the building blocks of life found so far on Mars.)
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  “Mars has fooled us again!” says Sushil Atreya, a planetary scientist at the University of Michigan who is part of the team reporting the odd oxygen results in the Journal of Geophysical Research: Planets.
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  Though it’s tempting to think of photosynthesis when hearing about oxygen in a planet’s atmosphere, non-living processes are known to make oxygen on Mars, and these findings are not necessarily evidence of life. Instead, the results highlight gaps in our understanding of the red planet’s surface chemistry—holes that must be filled if we are to hunt for direct evidence of past or present Martians.
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  Next summer, four nations will be launching missions to Mars to further that goal, including NASA’s Mars 2020 rover, which will cache samples for future return to Earth. The European Union and Russia have also teamed up on the ExoMars mission, which includes the Rosalind Franklin rover. That robotic explorer will drill more than six feet into the Martian surface, exploring the red planet’s inner chemistry better than ever before. (Here’s how the InSight NASA lander discovered that the planet experiences mysterious magnetic pulses at night.)
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