Methane on Mars. Scientists have located the likely source of the gas

The first traces of methane in the atmosphere of Mars were recorded by the Mars Express probe shortly after it began its exploration in 2004. This detection has been the subject of disputeoin the scientific community. Discussed mainlyownie over the accuracy of the readingow. Many scientistsow challenged the study, whichore were based on a single dataset. The atmosphere was heated up by the Curiosity rover, whichory in 2013 also detected methane on Mars.

Methane attracts so much attention because it is thought to be a marker of life on distant planets. On Earth, it is produced by living organisms, which fired the imagination of searchers for extraterrestrial life. But methane is also generated by geological processes. Methane molecules decay rapidly in the atmosphere, so any detection of methane in the Martian atmosphere means that it must have been released relatively recently – even if the methane itself was produced millions or billions of years ago and has lain deposited beneath the surface until now.

Now the international compositeo³ expertoin the porownited observations made by Curiosity in June 2013 at Gale crater with data recorded by the Mars Express probe, whichohe next day flew over the crater. In addition, the researchers conducted two rownoleged experiments to determine the most likely source of the gasomethane release on Mars. Research scientistsoin have been published in the pages of the journal „Nature Geoscience”.

The study used a new observational technique that allows the collection of several hundred measurementsoin one area in the krotkim period. The teams developed roalso improved analysis techniques to make the best use of the data.

– Ogolnie we did not detect any methane, except for one specific detection of about 15 ppm (parts per million). This was a day after the Curiosity rover recorded about 6 ppm of – said Marco Giuranna of the Institute for Space Astrophysics and Planetology in Rome, first author of the publication and head of theowny researcher of the PFS spectrometer, using ktoThe next day the Mars Express probe flew over the crater. – Although the detected concentration is a relatively small amount, it is quite unusual for a Mars. Our measurement corresponds to the detection of about 46 tons of methane, whichory was present in an area of 49,000 kilometersoin square – added.

Ten other measurementsoIn made by the Mars Express probe did not record methane. This corresponded to the period during which theoCuriosity detected trace amounts of this gas.

When the data from Curiosity arrived, researchers speculated that the methane formed on poNorth of the rover, whichory operates in the Gale crater. This was suggested by the southerly winds blowing in theotime in that region. Scientists thought the release likely occurred inside the crater.

– Mars Express data taken a day after Curiosity’s detection changes the interpretation of where the methane came from, especiallyolnie when considering global patternsoin the atmospheric circulation along with the local geology. Based on the evidenceoin geologic and methane quantities, whichory we measured we believe that it is unlikely that the source of theoThe bed was located in the crater – admitted Giuranna.

Scientists conducted two independent analyses to locate the source of theobackground of methane. They divided a wide region wokoGale crater into squares of about 250 by 250 kilometersoin square. In one study, the cooBrussels researchers used computer simulations to create one million emission scenarios for each square to predict the probability of methane emissions for each location. The simulations took into account the measured data, expected atmospheric circulation patterns, and the intensity and timing of methane release.

RoItalian geologists, together with colleagues from the US, analyzed the region wokoł of Gale crater looking for places where methane leakage mohead occur. This process is well known on Earth and occurs along faultsoin tectonic and pol of natural gas. Depending on the location, there are rohe intensity of gas release. For example, gas emissions from active volcanoesoin mudflows is usually continuous with slight fluctuations, but also with sudden strong bursts, while other spills may release gas intermittently.

Episodic release of gas – that is, generally a long spokoj without emissions between krotkot sustained pulses – is typical of gas expulsion from small or „dying” leakow or due to seismic events. On Mars, episodic gas release can roalso arise during a meteorite impact, causing the emission of gas trapped beneath the surface.

– We identified tectonic faults thatore can extend below the area where lod. Since permafrost is an excellent seal for methane, it is possible that lod can imprison subsurface methane and release it episodically during fault displacementow or ice cracks – explained wsporesearch author Giuseppe Etiope of the National Institute of Geophysics and Volcanology in Rome.

– Interestingly, we noted that atmospheric simulation and geological assessment, performed independently of each other, suggest the same region of origin of methane. Our results support the view that methane release on Mars may be characterized by small, transient geologic events rather than a continuously replenishing global presence, but we also need to better understand how theob methane is removed from the atmosphere and how to reconcile Mars Express data with results from other missions – noted Frank Daerden of the Royal Belgian Institute for Space Aeronomy in Brussels, roThe co-authors alsoorouter of the publication.

SourceoSource: ESA, photo. ESA/ATG medialab/ Mars: ESA/DLR/FU Berlin/ CC BY-SA 3.0 IGO