The presence of methane or its compounds scientists traditionally seen as a sign of potential habitability of planets, as this gas may be the product of vital functions of soil bacteria. In particular, researchers are very encouraged by the presence of methane on the same Mars. And is it really can be a "symptomatic of life"? It is doubtful...

Now it is believed that large quantities of methane can accumulate on earth-planets only if there living organisms. Certain hopes in this respect on Saturn's moon Titan. The temperature on its surface only 94 degrees above absolute zero (- 179 degrees Celsius). There's no liquid water, however, there are lakes of liquid methane.

Not so long ago, employees of the research center Ames Chris McKay and Heather Smith from the International space University in Strasbourg was able to theoretically prove that right on the surface of Titan may exist live microorganisms! In their opinion, some of the methane in the atmosphere of the satellite is a product of the metabolism of bacteria.

Experts believe that on Titan may exist and special forms "methane" life, only, of course, hardly inhabitants Titanium like us...

Though there are similar "methane" evidence for the existence of life on Mars. So, there methane found in places where the climate is warmer, or in the warm seasons (say, in summer in the Northern hemisphere). However, any bacteria on Mars is not yet found. However, there are suggestions that the Rovers have already met local bacteria, but "opoznal", they successfully destroyed, apparently, attributing them earthly origin.

Meanwhile, it was found that carbon-rich micrometeoroid of the asteroid belt dominated by carbon celestial bodies, burning in the Martian atmosphere, put down the components for the formation of methane under the influence of ultraviolet rays relatively easily penetrating into the thin atmosphere of the red planet. However, the percentage delivered them to Mars methane is very small. Besides, it is not clear why the concentration of methane on Mars is so heterogeneous.

However, says geologist from Imperial College London, Richard Court, on Mars, at least you can send a spacecraft, but with exoplanets everything is much more complicated. "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", believes the Court.

The fact that many star systems experienced a phase of active bombardment planets micrometeoroids and larger heavenly bodies. By the way, does not escape this and our Solar system. For example, if it falls to the Ground only 40 thousand tons of space material per year, and to Mars - 12 thousand tons, then in the period of the late heavy bombardment that figure, according to various estimates, exceeded present in 1-10 thousand times. Thus, for 100 million years the bombing on the Ground "spilled" about 33 trillion tons of micrometeoroids, and to Mars - 1.7 trillion tons. According to Richard Court, all this could lead to the formation of such quantity of methane that could be observed on the planet earth-like, where indeed there is life.

In this regard, even originated the term "false methane". I mean the methane that is not related to life on that planet. For example, a similar effect was observed near the star Gliz 581, which was discovered and "super-earths", and the disk with a large number of small celestial phone surface Temperature was found in this system, planets, according to estimates, should be -179 degrees Celsius in the area between 0.63 and 1,66 astronomical units. In these cold worlds life is possible on the basis of liquid methane.

But the same "methane" worlds may exist around solar-type stars, because Titan is also in the Solar system... "Titanti" and other inhabitants "methane" worlds can instead oxygen to breathe hydrogen, acetylene and ethane, and instead exhale carbon dioxide methane. Therefore, their existence can "calculate" reduction of the concentration of hydrogen, acetylene and ethane near the surface of the planet. This can be an additional criterion in favour of habitability, then just as the presence of methane is not yet evidence that the planet one lives, even microorganisms.