Scientists Find Likely Source of Methane on Mars

Now scientists confirm that another spacecraft, known as Mars Express, detected methane in the same area, just a day later, apparently confirming that first detection.

Methane doesn't last long in the atmosphere, so any detection of the gas needs to be done quite quickly after it is released.

"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 500 km east of Gale", said Marco Giuranna from the varsity.

In the 15 years since a European probe reported traces of the gas in the Martian atmosphere, a debate has raged over the accuracy of the readings showing methane, which on Earth is produced by simple lifeforms. Now, NASA's Curiosity rover and the European Space Agency's Mars Express have confirmed the gas' presence in the air above Gale Crater.

There are a variety of ways methane might be produced on Mars.

Analysing the isotopic signature or atomic "strain" of carbon in the methane may help scientists determine whether or not the gas is sign of life.

"Our results support the idea that methane release on Mars might be characterized by small, transient geological events rather than a constantly replenishing global presence", said Frank Daerden, researcher at the Royal Belgian Institute for Space Astronomy in Brussels.

The scientists led by Dr Marco Giuranna, from the National Institute of Astrophysics in Rome, wrote: "The results presented in this work not only corroborate previous detections by Curiosity but, in a broader perspective, might change our view of methane occurrence on Mars". The presence of methane in the vicinity was confirmed by readings taken 24 hours earlier by NASA's Curiosity rover. The next day, ESA's Mars Express probe captured air samples with a methane concentration of 15.5 parts per billion as it whizzed through the atmosphere above Gale Crater.

If microbes still exist, they are one possible source.

The scientists used the orbiter's planetary fourier spectrometer (PFS) to look for methane in and around Gale crater from December 2012 to July 2014. Their findings suggest methane releases are extremely rare and that the gas swiftly disappears.

This kind of thing happens on Earth, typically along tectonic faults and at natural gas deposits. Methane can be made as a downstream product of serpentinisation. Geologists from Italy and the US also carefully examined the region around the Gale crater for methane-releasing features.

In a study published Monday in the journal Nature Geoscience, the scientists present their theory: that the "geological faults" in the Aeolis Mensae region could have broken permafrost nearby and released methane that may have been trapped within it.

Shortly after Curiosity landed in 2012 in the Gale impact crater, "I chose to conduct a long-term monitoring of the Martian atmosphere" at this location, says the researcher, whose study is published in Nature Geoscience.

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