Methane is a particularly interesting gas to look at on other planets, as it can be produced by microorganisms.
But no evidence has been found that there is anything like it on the planet Mars.
However, there have been several measurements of methane since 2003 on the red planet, but researchers do not know where the gas comes from.
NASA's Curiosity rover measures, among other things, the atmosphere on Mars, and in June 2013, reported a sharp increase in methane in Gale Crater, which the rover explores. This gas is not in the atmosphere, but it appears and disappears.
This measure is confirmed by the Mars Express spacecraft, according to a new article in the journal Nature Geoscience. Researchers behind the orbit of Mars since 2004 believe they have found traces of the same methane peak in 2013 in measurements, which originate from a location near the Gale crater.
But where does the gas come from?
The researchers spent two years with many different measurements from the same area, but no other measurements showed any trace of methane except the only time in 2013.
It may mean that methane is rarely emitted, occasionally, at least near the crater Gale, the crater more than 150 kilometers wide, where Aeolis Mons mountain extends for 5,500 meters in the middle.
Although micro-organisms may be the source of methane, this is far from the only explanation.
There are several possible mechanisms, including methane stored in permafrost, ice or various variations of rocks below the ground on Mars, which are sometimes released through cracks or glitches on the planet.
Varies according to seasons
NASA also says that Curiosity sees a pattern in methane emissions, meaning that methane emissions peak during the summer months around Gale Crater.
Mars also has different seasons. The idea is that it emits more methane when the surface is warmed by the summer sun, according to Nature.
On a summer day on Mars, Curiosity measured up to 20 degrees a day, but temperatures vary a lot compared to here at home. At night, it can reproduce below -100 degrees.
Giuranna Independent verification of a methane peak on Mars and a region of origin east of Galé Crater. Nature geoscience, 2019. DOI: 10.1038 / s41561-019-0331-9. summary
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