A new part of the methane puzzle that disappears on Mars has been discovered. Data collected from the Orbit mission of the Mars Express European Space Agency (ESA) were investigated to look for correlation with the data collected from the surface by the rover Curiosity.
Earlier, Curiosity data showed that methane was present in the Mars atmosphere but this methane was not detected by Mars Express. Now re-analyzing satellite data shows that methane was only present in one place one day after reading Reading.
The analysis used a new observation technique that collected a few hundred measures in a short period of time. This technique is more accurate than the prior art and was able to determine only 15 parts of methane per billion in volume of atmosphere.
Although it seems that datasets like Mars Expressa and Curiosity are more relevant to those before, the source of the detected methane is still a puzzle.
"Our new Marsa Expressa data, recorded the day after Curiosity's recording, changes the understanding of where methane comes from, especially when considering global atmospheric circulation patterns together with local geology", Marco Giuranna from the National Institute of Astrophysics, the Astrophysics and Planetology Institute in Rome, Italy, and the author of the article, says the press release.
Scientists believe that methane could be trapped in ice beneath Mars's surface and elevated through tectonic casualties. Alternatively, meteorite impacts could have caused cracks that dropped the gas below the surface.
Overall, existing evidence suggests methane is present on Mars due to occasional geological events that release small amounts of gas captured below the surface, perhaps thousands of years. Methane does not seem, as some thought, to be constantly renewed on the planet. So Mars could be alive nowadays, but it seems less likely that there is life there now.
More information on this subject is expected to be collected by the Trace Gas Orbiter craft, part of the ExoMars mission, which is currently gathering information on the composition of the Martian atmosphere and which can reveal more about where this mysterious methane comes from.
The findings were published in Nature Geoscience.