Evidence of life on another planet is found; What does that mean?

For the first time, scientists detected on an alien planet the chemical impressions of gas that, on Earth, are produced only by biological processes.

The discovery, published this week at The Astrophysical Journal Lettersit is considered the strongest indicative of the possible existence of life beyond the solar system .

The two gases – dimethyl sulfide and dimethyl disulfide – They were observed on the planet called K2-18 B, by the space telescope James Webb. On Earth, they are generated exclusively by living organisms, especially by microbial life, such as marine phytoplankton.

That suggests that the planet could have microbial life. But the researchers emphasize that they are not announcing the discovery of living organisms, but of a possible bioassinature – The presence of substances that indicate a biological process happening there.

Is the presence of these gases a certainty that there is life?

Dimethyl sulfide (DMs) and dimethyl disulfide (DMDs), both from the same chemical family, are considered important bioassine in exoplanets.

The webb found that one or the other, or possibly both, were present in the planet atmosphere with a confidence level of 99.7%, which means there is still a chance of 0.3% of observation being a statistical chance.

Both are produced on Earth only through biological activity. That is, with the knowledge we have so far, there is no way to explain the presence of these gases without being produced by living microorganisms.

However, there is no way to discard the possibility that there are other explanations for the presence of these gases in the K2-18 B that we do not yet know.

In November 2024, another group of researchers published in the same journal Evidence of the presence of DMs in a comet.

The research suggests a new way of production of DMs, which uses basic elements available in space and does not depend on the presence of life. It also brings to light the possibility that DMS may have been taken to other planets through comets that carry the substance.

The possibility that the gases have been brought from elsewhere, however, it seems less likely to take into account the amount observed in K2-18 B: atmospheric concentrations of more than 10 parts per million per volume, thousands of times more than concentrations of DMs or DMDs on Earth.

The discovery is promising, but many additional work will still be needed before it is possible to confirm whether bioassine in K2-18 B even indicates the presence of life or not.

What kind of life would this be?

The K2-18 B is 8.6 times more massive than the earth and has a diameter about 2.6 times larger than the planet.

It orbits in the “habitable zone”-a distance from a planet compared to its star where liquid water, a fundamental ingredient for life, may exist-around a smaller and less bright red dwarf star than the sun, located about 124 light years from Earth in the lion constellation.

“The only scenario that currently explains all the data obtained so far by JWST (James Webb Space Telescope), including past and present observations, is one in which K2-18 B is a full-life ocean world,” said astrophysicist Nikku Madhusudhan of the Cambridge University Astronomy Institute, the lead author of the study published this week.

The so -called ocean worlds refer to the possibility of existing exoplanets covered by an ocean of habitable liquid water and with a hydrogen -rich atmosphere. These oceans could be inhabited by microbial life, which could even be similar to what we find in the oceans of the earth.

Asked about possible multicellular organisms or even intelligent life, Madhusudhan said, “We will not be able to answer this question at this stage. Basic assumption is simple microbial life.”

*With information from Reuters

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This content was originally published in evidence of life on another planet is found; What does that mean? on the CNN Brazil website.

Source: CNN Brasil