Methane. Chemical formula CH. with₄, it is a powerful green house gas, Which we may have to hunt soon. like we’re already following Carbon dioxide (CO)₂) To limit Global warming anthropogenic. but Researchers from the University of California at Santa Cruz (United States), they propose to hunt for methane in a completely different place than our Earth’s atmosphere and for a completely different reason. because in Atmosphere Of exoplanets, it may mark the presence of extraterrestrial life forms.

Methane as a Biosignature – a sign that some form of life has passed. astronomers Especially interested in this today. because it may be detectable in the environment of some exoplanets James Webb Space Telescope (JWST). but be careful! Methane can, in fact, also be emitted by non-biological processes.

While awaiting JWST’s first observations, the researchers balked at this question. To follow up on their argument, it’s good to remember that methane doesn’t stay in the atmosphere for long. Within a few years, it was destroyed photochemical reactions, Thus, the only explanation for trace amounts of methane in the atmosphere is the presence of a source that emits it more or less continuously.

Biosignature or not, the important thing is to avoid errors

And it is possible that non-biological sources also emit a lot of methane. From Volcanoreactions that occur for example in mid-ocean ridge type environments, fireplaces area of ​​hydrothermal vent or subduction tectonics or influence comet orasteroids, But what researchers at the University of California suggest today is that these sources will necessarily parallel other observable clues that betray the origins of all this CH.₄, degassing For example, volcanoes would add both methane and carbon to the atmosphere of rocky exoplanets. carbon monoxide (CO). What organic sources will not do.

According to astronomers, therefore, if methane can provide an important clue, it remains only a simple piece of the puzzle. extraterrestrial life, and study published in Proceedings of the National Academy of Science (United States) provides some guidelines to avoid “false positive”, To prevent researchers from missing out on the actual biosignature, unfortunately.

For example, a. Feather rocky planet Orbiting a star similar to our Sun, methane could begin to form a strong biosignature if said planet’s atmosphere also contains CO.₂ and if ch₄ Much more abundant than CO. but in Case In an extraterrestrial environment, there is still much to learn. And researchers at the University of California are calling for more work on the topic. Studies that can analyze even the most unusual mechanisms of non-organic methane production. as much as possible to avoid errors of interpretation of the results that may be transmitted too soon James Webb Space Telescope,