In more conventional science fiction sagas, aliens usually resemble the living beings we know. Many times, they are even intelligent and walk on solid planets like ours. However, reality can be more strange. With that hypothesis works the astronomer team of the University of Cambridge Nikku Madhusudhan who has just announced what, according to him, is “the strongest evidence so far” of life outside the earth. Other experts, however, believe that it has no data to affirm such a thing. The new world inhabited would be K2-18B, a planet to 120 light years from here similar to Neptune, with twice and a half the size of the earth, orbiting a distance of its star that would allow it to have a liquid water ocean covered by an atmosphere of hydrogen. These worlds, believe Madhusudhan, can be suitable for life. Now, using the James Webb space telescope, two gases, dimethyl sulfide, or DMS, and dimethyl disulfide, or DMDS have detected in that exoplanet, which on earth are mainly produced by microbial life such as marine phytoplankton (algae) or bacteria. More information “This is a revolutionary moment Finding, ensuring that “it is the first time that humanity has seen potential biofirms on a habitable planet.” Although he acknowledges that a lot of work is needed to confirm the finding of extraterrestrial life, the researcher believes that the best explanation for his observations is that K2-18B is covered by a temperate and alive ocean. Ignasi Ribas, director of the Institute of Space Studies of Catalonia (IEEC) and CSIC research professor, considers that it is an “interesting” discovery, but that it is far from allowing to affirm that life has been found. “It is a single group advertisement, which will have to try to replicate others, it is a very preliminary moment,” he says. The results have been published in The Astrophysical Journal Letters, a minor scientific journal. These types of results, the sources consulted coincide, to show what the expert says and although they offer a 99.7%security, they should have been published in a first -order magazine such as Science or Nature. According to Ribas, this team is leading the research around this exoplanet with previous controversies. In 2019, the presence of water was announced, which finally ended up being methane, and in 2023 very weak signals of DMS were published, a sign that has now been observed with more intensity. “Then, shortly after the finding, articles began to be published that explained the presence of the compound in the planet’s atmosphere through mechanisms other than the biological activity and predict that in the coming weeks the same will begin to happen,” adds Ribas. James Webb is a telescope so powerful that it is able to analyze the chemical composition of the atmosphere of a planet through the light of the star that crosses it. With that technique, the atmospheres of planets similar to K2-18B are already being analyzed in search of more similar signals on similar planets that allow us to conclude that it is not an exotic phenomenon that only occurs in one place. “There are many minineptunos and that would increase the number of sites in which you can look for life,” says Ribas.K2-18 B has 8.6 times the mass of the earth and a diameter approximately 2.6 times greater than that of our planet. Orbit in the “habitable zone” – a distance where liquid water, a key ingredient for life, can exist on the planetary surface – around a smaller and less bright red dwarf star than our sun, in Leo’s constellation. Another planet has also been identified by orbiting this star. It is hypothesized that its oceans are warmer than those of our planet. When asked, in the presentation of this finding, about the possibility of multicellular organisms or even intelligent life, Madhusudhan said: “We cannot answer this question at this time. The departure hypothesis is that of a simple microbial life.” The scientist mixed his enthusiasm with caution. “First, we need to repeat the observations two or three times to ensure that the signal we observe is robust and increase the significance of detection to the point where the chances of a statistical chance are lower than approximately one million,” he said. “Second, we need more theoretical and experimental studies to determine if there is another abiotic mechanism (which does not involve biological processes) that generates DMS or DMDs in a planetary atmosphere such as that of K2-18 B. While previous studies have suggested them as robust biofirms even for K2-18 B, we must keep the mind open and explore other possibilities,” he concluded. The findings represent great uncertainty about whether the observations are due to the presence of life. “No one is interested prematurely that we have detected life,” warned the scientist. Other experts demand even more caution. The study finds a “sigma” probability of biological activity, something that, according to experts, is insufficient: at least it should be 5 sigma. David Clements, astrophysicist of the Imperial College of London, has told the United Kingdom SMC portal: “This is really interesting and, although it still does not represent a clear detection of dimethyl sulfide or dimethyl disulfide, it is a step in the right direction. To be able to affirm with certainty the existence of life on this planet, we would need a solid detection, greater than 5 sigma, a clear demonstration of a clear demonstration. Biomarker and not from another molecular species that passes through biomarker. In the experiment they are notable enough to exclude the possibility that they are due to random, except in rare cases, rareness equivalent to launching a currency 10 times and obtaining the same result every time. ‘Five Sigma’ is a stricter threshold, it is equivalent to launching a currency 20 times in a row and obtaining the same result each time. It is still possible that we have simply been lucky, and the more data we observe, the greater the probability of making an observation that is only the result of chance. But an observation of five Sigma is something that would only arise by chance in exceptionally rare cases, so we can have a lot of confidence that it is not a fortuitous finding. ” Astronomers. But, remember, we are not at that point yet
