In June 2013, NASA's Mars Curiosity rover detected spikes of methane on the Red Planet's 96-mile-wide Gale crater. The probe has since found that the levels of the gas varies, rising and falling with Martian seasons.
Methane As Potential Indicator Of Life On Mars
Scientists wanted to know the source of methane on Mars because of its potential implications. For one, methane is a gas associated with life because it is produced by living organisms, albeit it can also be generated by geological processes. Scientists wanted to find out if methane on the Red Planet is created by some forms of alien life.
Researchers now appear to have inched closer to solving the mystery. In a new study published in Nature Geoscience, researchers appear to have found the source of methane on Mars.
Marco Giuranna from the Institute for Space Astrophysics and Planetology in Rome, Italy, and colleagues looked at data gathered by the planetary fourier spectrometer (PFS) on the European Space Agency's Mars Express orbiter.
Finding The Source Of Methane
The researchers wanted to find more evidence of the colorless and odorless gas on the Red Planet, so they looked for methane in and around Gale crater from December 2012 to July 2014. The PFS spotted the gas only once, on the same day, the Curiosity detected the spike in methane
"Based on geological evidence and the amount of methane that we measured, we think that the source is unlikely to be located within the crater," Giuranna said.
To look for the source of the emission, scientists divided the region around the Gale crater into a grid with squares on each side and then used computer models to simulate different emission scenarios in each of the squares. They also looked for features that may release methane such as fault lines and fault intersections.
Geological Process May Have Released Trapped Methane
The findings point at the same region known as Aeolis Mensae. Researchers said the location has a number of geological faults that may have fractured nearby permafrost, causing the release of trapped methane inside. It is also possible that incoming meteorites broke the ice open.
"Our independent geological analysis also points to a source in this region, where faults of Aeolis Mensae may extend into proposed shallow ice of the Medusae Fossae Formation and episodically release gas trapped below or within the ice," the researchers wrote in their study, which was published on April 1.