The mystery of methane in the Martian surface long been a subject of heated debate.

Some astronomers based on the fact that methane most places on Mars where it is warmer, and when it is warmer (for example, in summer in the Northern hemisphere), believe that the products of life activity of soil bacteria. But other people often take this "different explanation", extracting methane from lightning Martian storms, and even from meteoroids burning in the atmosphere of Mars and supplying components for there methane under the action of ultraviolet radiation, which is relatively freely into the thin atmosphere of Mars.

And to put an end until no one can. First prove their point of view only if the Rovers will find such bacteria (and it is not easy, benefit, under some assumptions, they have already found them, but when "identification" safely destroyed). The latter admit that, by all calculations, and lightning, and meteoroids can deliver to Mars a few percent of the methane, which, according to spectral analysis, there is there. Again, their hypothesis still does not explain "spots" of methane on Mars...

However, as says Richard Court, a geologist from Imperial College London (UK), the problem with Mars is solved at least fundamentally: we can send the corresponding device. But with exoplanets, this will not work, and then astrobiology can wait a serious problem.

It is now believed that the methane in really large numbers can be generated on earth-planets only living organisms (see Land). However, the study sources of methane on Mars has revealed the possibility that carbon-rich micrometeoroid originating from the asteroid belt dominated by carbon celestial bodies, deliver components for the formation of methane is already in place.

Of course, the hypothesis of the meteoroids can hardly explain why the methane on Mars only appears when in the heat. But in respect of exoplanets it can be useful.

"This may be a problem, because the search for life on exoplanets depends on remote observations (say, spectroscopic analysis of their atmospheres), as was the case with the discovery of methane on Mars", emphasizes Richard Court. The fact that many systems observed by astronomers today, pass through a phase of extremely active bombing planets micrometeoroids and larger celestial bodies, as it was in the Solar system during the late heavy bombardment. For example, if today the Earth receives only 40 thousand tons of micrometeoroids a year, and Mars - 12 thousand tons, during the late heavy bombardment that figure, according to various estimates, was 1 000-10 000 times more. Say, for 100 million years bombardment of the Earth has about 33 trillion tons of micrometeoroids, and Mars - 1.7 trillion tons.

According to the researcher, in the midst of such events on the exoplanet we would see in its atmosphere too much methane is so much that could not distinguish her from terrestrial planets where life already exists.

In this connection, it is not superfluous to recall the star of the Gliz 581: astronomers have seen in one and the same system and the "super-earths", and the disk with a large number of small celestial bodies that can cause the effect of " false methane in the atmosphere closest planet earth.

A study published on 6 September in the journal of the Planetary and Space Science.

Based on the materials Astrobiology Magazine.