In 2013, NASA’s Curiosity reported about the detection of methane on Mars. This was a significant finding, as methane was detected at various sites on Mars but it simply disappeared after a time. There has been always a debate on the amount and the nature of methane present in Mars. Now, the presence of methane has been confirmed by the Mars Express.
This is an interesting finding as terrestrial methane can be made either by living organisms as well as by geological processes. As methane has a short lifespan in the atmosphere of Mars, so detection of the gas means that it has been released recently. The finding has been confirmed by Planetary Fourier Spectrometer( PFS) which is present on Mars Express.
Marco Giuranna, PFS’ principal investigator reported that they detected about 15 parts per billion by volume of methane in the Martian atmosphere. Parts per billion is a small amount but this is a remarkable finding for Mars. It is estimated that 46 tonnes of methane was present in 49,000 square kilometres on an average.
After the detection by Curiosity, it was thought that the source of methane might have been the north of the Curiosity rover and it was released from the Gale Crater which is the landing location of Curiosity.
But the question remains on the origin of methane. There are multiple opinions on this. One way is by micro-organisms. If the methane is produced by them a long time ago and it is trapped in ice, then the melting of ice can release it in the atmosphere.
Methane can also be produced by geological processes which do not require living beings at all. It can be produced as a by-product of serpentinisation, in which mineral alteration occurs in the crust with help of heat and water.
Researchers searched the region of Gale crater for features from which gas seepage can be expected. In Earth, this process is very well known to occur along tectonic faults and gas fields. Giuseppe Etiope, from the National Institute of Geophysics and Volcanology in Rome, reported that tectonic faults were identified which may extend far below the region expected to contain ice. Permafrost is a brilliant source in which methane gets trapped. It is very much possible that the methane is released along with the faults which pass through the ice. Hence this investigation shows that we may be familiar with the surface of Mars but we do not have much knowledge on its interior.