A seasonal rise and fall in the background methane levels on Mars have been tracked by scientists over the years, but a pattern has not yet been established of the transient plumes.
NASA’s Curiosity Rover detected the highest level of colourless, and odourless gas only recently, over the course of its 7 year mission on Mars. This discovery makes it much more likely that life exists on the red planet, even if it is only microbial.
Follow up experiments by NASA over the weekend have found that methane gas has gone back to its background levels as announced on Tuesday, indicating that the temporary spike in the gas was due to the transient plumes which was observed by Curiosity in the past. Scientists are motivated now, more than ever, to continue to measure the levels of the gas and reason out the behaviour of methane on Mars, according to Ashwin Vasavada, the project scientist at NASA’s Jet Propulsion Lab.
NASA has additionally said that Curiosity does not currently possess the instruments which will definitively determine the source of the methane, and whether it is a byproduct of living organisms, or geological functions.
A leading theory in the community states that methane is being released from underground reservoirs which were constructed by life forms which are now extinct. Though no active volcanoes exist on mars such as they do on Earth, it may be possible that methane is produced by the reaction of carbon from the carbonate rocks, or carbon dioxide, with the hydrogen from liquid water.
The mystery continues, but only for a time.