«The strongest clues to Biological activity outside the Solar System»: So the latest results obtained by a team of astronomers of the University of Cambridge were defined led by Nikku Madhusudhanwho analyzed with the telescope James Webb the exoplanet K2-18 b 124 light years from us in the constellation of the lion. Specifically, the new data of the NASA spatial telescope confirm the indications of the presence of Dimetyl Solfuro (DMS) and/or Dimetyl disolfuro (DMDS), two sulfur -based molecules, carbon and hydrogen in the atmosphere of this oceanic or “Hycean World” exoplanet.
This is an important news because these substances are produced only by anthropic activity and by phytoplankton (the Dimetyl Solfuro gives the Salset its characteristic smell) and not known non-biological processes capable of generating these two molecules, therefore their presence on K2-18 B-if confirmed-could mean that The planet is inhabited by microorganisms Oceanic photosynthetics. The hypothesis is not so peregrine, because what we know on K2-18 B suggests that it is a “super-terme” (it has a diameter 2.6 times greater than the terrestrial one) than It is found in the habitability band of its star and would be covered with a global liquid water ocean.
However, the detection of DMS and/or DMDS has not reached the statistical significance necessary to affirm with certainty that those molecules are actually there, so it would be decidedly premature say that we found extraterrestrial life tests on other planets.
The story of the exoplanet K2-18 B: what we have discovered so far
The planet K2-18 B was discovered in 2015 from the space telescope Kepler and immediately attracted attention to its potential habitability, but jumped to the honors in the news already from 2019 When the Hubble Space Telescope discovered the presence of water vapor in the atmosphere of the planet. The turning point took place in 2023when James Webb found clues to the presence of DMS, the importance of which we explained above, in addition to the discovery (this time confirmed) of carbon dioxide And methane: It was the first observation of carbon -based compounds (the element of life) in the atmosphere of a planet in the habitable band of its star.
The scientific interest on K2-18 B has risen to the point that new observations were commissioned in 2024 with James Webb. The astronomers collected the data, they analyzed them with care and are now publishing the results: the clues on the DMS and/or DMDS in the atmosphere of the exoplanet have been confirmed with one greater statistical significance (the highest ever obtained for a molecule that we do not know how to explain in the atmosphere of a planet except through biological processes) but still Not enough to talk about a real scientific discovery. According to the authors of the research, they are needed another 16-24 hours Webb’s observation to be able to have a definitive confirmation or denial.
James Webb’s new observations
The statistical significance on the detection of DMS and/or SMDS on K2-18 B has increased not only thanks to the new data collected by James Webb in the infrared nearby, but also thanks to New observations in the medium infrared (i.e. with wavelengths further away from those of visible light) through the instrument Miri (Mid-Infrared Instrument).
Even in the medium infrared, astronomers have noticed the clues of the presence of Dimetyl Solfuro and Dimetyl disolfuro, which therefore add up to those in the nearby nearby, but it is important to reiterate that so far These are clues and not a certain discovery.
Is there life on K2-18 b? The importance of the new study
If these data should be confirmed by future observations, we would be talking about a world with possible oceans of liquid water on the surface and in whose atmosphere there would be very high concentrations (Thousands of times those found in the terrestrial atmosphere) of molecules whose non-biological production processes are not known. It is therefore understandable that the new study on the atmospheric composition of K2-18 B is making talk of itself: it could mean, at least in theory, that the planet guests photosynthetic life forms!
As Madhusudhan himself repeatedly reiterated, however, it is essential to be cautious and maintain that healthy skepticism typical of science. The validation of a scientific discovery is in fact a long and accidental process, and where we are now a possible announcement of extraterrestrial life passes through it. For example, even if further analyzes would come to give the detection of Dimetyl Solfuro and Dimetyl disolfuro the official status of scientific discovery, it should still be excluded beyond any reasonable doubt that those molecules have not arrived there through non -biological processes that are not known at the moment. As you can understand, it’s not a simple problem.
The story however it deserves attention and interest And all that remains is to follow further observations and new analyzes of the data collected.
