Curiosity detects methane fluctuations in Martian atmosphere

The Curiosity rover has detected methane fluctuations in the atmosphere of Mars, a situation that opens up new avenues of investigation for scientists to determine the source producing the gas.

Most of the methane in Earth's atmosphere is produced by biological activity. This is the main conclusion of a study published Tuesday in the US journal Science and which also opens up a new line of research into what the mechanisms are by which the gas, the chemical designation of which is CH4, is eliminated from the atmosphere of the red planet with unexplained rapidity.

Participating in the research are two Spanish scientists, Javier Martin Torres, with the Andalusian Institute of Earth Sciences, and Paz Zorzano, with the Astrobiological Centre.

According to the study's authors, the work solves "the long-standing controversy" regarding the presence of methane on Mars that began more than a decade ago when the gas was first detected using Earth-based telescopes and later verified by orbital probes.

Current measurements of the periodic increase in methane concentrations in the Martian atmosphere were made by Curiosity's tunable laser spectrometre.

The results indicate that, although the methane levels in the Martian atmosphere (specifically in the bottom of Gale Crater) are generally lower than what scientific models predict, the amount of gas is frequently replenished.

That implies that methane is produced periodically by an unknown source and then dissipates, only to be replenished again later, the article stated.

Since methane is a product that results from biological activity -- and virtually all of the CH4 in Earth's atmosphere, for instance, originates in that way -- the detection of it on Mars raises hopes that biological activity, perhaps from microbes, may be under way on the red planet as well. Methane can also be produced by geological processes, however.

The concentration of methane in the Martian atmosphere is reported to be around 0.7 parts per billion by volume, but the concentration can spike up to about 10 times that amount over the course of 60 Martian days, which are about three percent longer than an Earth day of 24 hours. Six weeks later, the apparently recurring methane "belch" has completely disappeared.