Last week Curiosity discovered methane on Mars the most. The company's laser spectrometer registered a methane peak of 21 volumes per billion (ppbv) at Gale Crater, a region the rover has been exploring since its landing in 2012.
In general, methane has a global average of 10 ppbv on Mars, which is why NASA conducts follow-up observations to determine where the unusually high concentration comes from.
What makes this so interesting is our knowledge of the sources of methane: it can be produced by living things. Tracking down the methane source on Mars could therefore be a way to find out if there are microbes that live in the extreme conditions of the Red Planet.
But it is far too early to be aroused, as microbes are certainly not the only potential source.
"With our current measurements, we can not say whether the source of methane is biology or geology or even old or modern," said Mars researcher Paul Mahaffy of NASA's Goddard Spaceflight Center.
Curiosity and other instruments have performed some methane detection over the years, but the level seems to rise and fall, and methane seems to appear and disappear like a malignant spirit.
Only at the beginning of this year, the scientists realized two independent instruments had discovered the same methane in 201
And there are reasons to be cautious when coming to important conclusions. Here on Earth we have a fair amount of methane – about 1,800 ppbv in the atmosphere, of which 90 to 95 percent is produced by living or deceased creatures.
But if we seek elsewhere in the solar system, then there are also many geological processes that can produce abyssal methane without life. On gas and ice giants such as Jupiter, Saturn, Uranus and Neptune, much methane has been produced by chemical reactions.
Pluto has methane ice. Saturn's moon Titan has lakes of liquid methane. The connection is not rare in the solar system, but to our knowledge, only the earth is a product of biological processes.
Another key is in the works. The European Space Agency's ExoMars trace gas orbiter, which can detect 50 volumes of methane per trillion in the Martian atmosphere, has been gathering data for just over a year and has so far gone completely blank.
] Whatever methane is on Mars, it could only be present on the surface for a very short time before it is released into the atmosphere. Whatever they find – whether curiosity rediscovers methane or not – NASA scientists will have more context to determine if the gas was transient or local in the Gale Crater.
You also had contact with the track ESA's Gas Orbiter team checks if atmospheric detection has been carried out at the same time. This could help to locate the gas source and calculate its lifetime in the atmosphere.
Whether the source of methane is biological or not, if we find out where it comes from, we will learn something new about Mars. Keep watching this room.