If you are not a chemist, astrobiologist, or scientist of any kind, and most of us are one of them, then a tiny, barely perceptible methane attack in the Martian atmosphere does not seem like a big deal. But they are gentle people. It is.
Because it could be a signal that some living process is at work. And even we non-scientists have at some point asked ourselves if the only life in the solar system, or perhaps the entire universe, is trapped here on Earth.
Let us discuss that.
Back there some time ago To be specific, in 2013 and 2014, NASA's MSL Curiosity Rover discovered methane spikes in the atmosphere of Gale Crater. And much earlier, in 2004, the Mars Express Orbiter (MEO) also detected methane in the Martian atmosphere. Methane is important because it can be an indicator of a living process. (Methane can also be produced by non-biological processes.)
Methane does not stay in the air for long. Once released into the atmosphere, it can be quickly destroyed by natural atmospheric processes. So any methane discovered in the Martian atmosphere must have recently been released, even though it could be trapped in subterranean rock formations millions of years ago, or even billions of years ago.
On Earth, most of the methane is produced by living things; B. microorganisms in sediment layers or in the gut of ruminants. Part of it is generated by abiotic or non-living processes, but finding methane on Mars is still potentially a big deal.
Now the European Space Agency, which operates the Mars Express Orbiter, has returned The data from June 1
This is the first time that a curiosity methane peak has been supported by other independent observations. These results will be presented in a new paper published on April 1 in Nature Geoscience.
The results of MEO are part of a new method for analyzing data from its spectrometer. The technique captures several hundred measurements in one area over a short period of time. The team behind the results also developed a new way to analyze the data.
" In general, we have not detected any methane, except for a clear evidence of about 15 volumes per billion methane in the atmosphere, which a day after Curiosity proved to peak at about six parts per billion " says Marco Giuranna from the National Institute of Astrophysics – Institute for Space Astrophysics and Planetary Science in Rome (Italy), the chief investigator of the PFS experiment, and the lead author of the paper, which reports the findings in Nature Geoscience .
15 parts per billion are not a large quantity. But it is still important.
" Although parts per billion are generally a relatively small amount, they are quite remarkable for Mars – our measurement corresponds to an average of about 46 tons of methane, which was in the region 49 000 square kilometers from our orbit "said Giuranna in a press release.
There is another correlation supporting this confirmation: Ten more observations of the Mars Express orbiter did not show methane, which was a period of time, and Curiosity also low
Where did it come from Originally, the wind came from the north at the Curiosity site in Gale Crater, where scientists believed that the methane came from inside the crater and was borne to curiosity by the wind does not seem so likely.
" Our new Mars Express data, the day after the inclusion of Curiosity have taken the interpretation of the origin of methane, in particular, taking into account the global atmospheric circulation patterns along with the local geology "said Giuranna. "Based on geological knowledge and the amount of methane we measured, we believe the source is unlikely to be inside the crater ."
If we talk about the source in this study then they are not talking about it, whether it is an abiotic (non-living) or a biological source. They only talk about the place of methane release.
In the graph above, scientists from the Royal Belgian Institute for Space Aeronautics in Brussels, who are working on the study, have grouped the area around Gale Crater into a network. For each square, computer simulations generated one million emission scenarios.
The simulations used measured methane, atmospheric circulation patterns and methane release properties based on the phenomenon called "gas leakage". Gas leakage is when entrapped methane is released from subterranean formations. The percentages reflect the likelihood that the methane comes from each grid square.
" We have identified tectonic errors that could extend below a region that is supposed to contain flat ice. Since permafrost is an excellent plug of methane, the ice here could trap underground methane and release episodically along the faults that break through this ice "says co-author Giuseppe Etiope of the National Institute of Geophysics and Volcanology in Rome. " Remarkably, we have seen that the atmospheric simulation and the geological evaluation performed independently of each other suggested the same region of origin of methane ."
Methane on Mars is still a mystery. But the pieces start to fit together. Now that another spacecraft, the Trace Gas Orbiter (TGO), is on Mars, we can expect more of the puzzle to be filled.
TGO is a joint mission between the European Space Agency and Roscosmos. It will make the most detailed analysis of the atmosphere of Mars. It arrived on Mars and started working in 2016, but recently started searching for methane.
As for the source of methane on Mars, it has to wait. We just do not know yet how it was produced and whether living organisms are responsible for it or not.