Mysterious oxygen spike seen on Mars puzzles scientists

The discovery showcases some of the chemical enigmas we need to untangle for future Mars missions to properly search for life.

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.

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.)

“Mars has fooled us again!” says Sushil Atreya, a

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