Mars methane surge spotted from space

Pablo Tucker
April 4, 2019

A waft of methane detected by Nasa's Curiosity rover on Mars may have been released from a layer of permafrost containing bubbles of the gas that was fractured by a geological event, researchers have said.

When Curiosity detected methane nearly six years ago, it was speculated that the gas originated north of the rover because the prevailing winds were southward, and that the release likely occurred inside the crater.

In an announcement today, the National Institute of Astrophysics (INAF) alongside the Italian Space Agency and National Institute of Geophysics and Volcanology revealed that methane emissions had been detected on Mars by a second source: Europe's Mars Express probe.

The near-invisible Martian atmosphere. During this time, the instrument noticed methane only once, which was on the same day Curiosity observed the sudden increase in methane on Mars. Since this time, Curiosity has discovered evidence of seasonal changes in methane. An worldwide team compared observations from the two separate spacecraft to find independent proof of methane on our neighboring planet resolving an intense, long-standing debate.

After the 2013 discovery of a methane source near Gale Crater by the Mars Express spacecraft, scientists confirmed their findings and published it in the Nature Geoscience journal.

Beyond its relevance to potential life on Mars, methane trapped in the Martian subsurface may also constitute a resource for future human activities on Mars, as methane has been discussed as a propellant for return to Earth needs and as a fuel and a chemical/industrial feedstock that could support a sustained human presence, according to Giuranna.

The Mars Express detection itself corresponds to 46 tonnes of methane out-gassing from an area covering 49,000 square kilometres.

"Methane is important because it could be an indicator of microbial life", he said.

In an attempt to trace the source of the methane, the scientists divided up a wide region around Gale crater into a grid with squares 250km on each side.

"In general we did not detect any methane, aside from one definite detection of about 15 parts per billion by volume of methane in the atmosphere, which turned out to be a day after Curiosity reported a spike of about six parts per billion", says Giuranna.

One study then ran a million computer-modeled emissions scenarios for each section while another team studied images of the planet surface for features associated on Earth with the release of methane.

"Remarkably, we saw that the atmospheric simulation and geological assessment, performed independently of each other, suggested the same region of provenance of the methane, which is situated about 311 miles (500 kilometers) east of Gale", Giuranna told The Guardian. "Two completely independent lines of investigation pointed to the same general area of the most likely source for the methane", he noted.

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