On April 17, 2025, astronomers announced that they had discovered extraterrestrial life traces on an exoplanet located 124 light years from Earth, thanks to the James Webb telescope. Nicknamed K2-18B, this exoplanet was already suspected of being a “ocean planet”. However, according to the Futurism media, the researchers may have been a little wrapped up and there is a flaw in the reasoning that led to their conclusion.
In the original study published in the review The Astrophysical Journal Lettersthe team of researchers, led by the Indian astrophysicist Nikku Madhusudhan, explained that he had spotted in the atmosphere of K2-18B of the dimethyle sulfide. It is an organic compound which, on earth, is exclusively produced by phytoplankton and other microbes. It was this reason that prompted scientists to assert that the most likely explanation of his detection on exoplanet was the presence of forms of life.
However, although dimethyl sulfide is an organic matter on our planet, evidence suggests that non -biological processes, elsewhere in the cosmos, could produce this same compound. This is in any case what the American scientific writer and scientific journalist says Corey S. Powell, in a thread on the Bluesky social network.
Don’t get worse
In fact, another study published in February 2025 indicated that it had detected the possible presence of dimethyl sulfide in the interstellar environment, the clouds of gas and dust which fill the space between the stars in a galaxy. Other scientists would have even discovered the biosignature on a sterile planet.
This information strongly questions the fact that the simple presence of dimethyl sulfide can constitute a certain indicator of extraterrestrial life. Despite the spectacular announcement of this discovery and its importance, the team seems to have preceded criticism by punctuating its study of nuances and warnings. However, Nikku Madhusudhan still declared that it was a “Revolutionary moment”. It is “The first time that humanity has seen potential biosignities on a habitable planet”.
Even if the dimethyl sulfide was a reliable biosignature, some scientists are even skeptical about its presence on K2-18B. Detection seems “provisional”said for example Edward Schwieterman, astrobiologist at the University of California and who has not participated in research. He suspects that the signal could disappear when other teams observe it.
“I think this is one of those situations where extraordinary claims require extraordinary evidencesaid astronomer Laura Kreidberg said. I am not sure that we have still reached the level of extraordinary evidence. ”
