The James Webb Space Telescope has found chemicals in the atmosphere of exoplanet K2-18b, 124 light-years away, that are produced only by living organisms on Earth. According to scientists, this is the most convincing evidence yet of possible life beyond Earth. The team of scientists detected the presence of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), which are commonly associated with seaweed and microorganisms on Earth. While it is theoretically possible for these substances to be produced without the presence of life, these are strong biosignaturas, i.e. chemical signs of life.
K2-18b is considered a so-called Hycean world. A planet with an ocean and a hydrogen-rich atmosphere. Traces of methane and carbon dioxide have also been detected here in the past. Scientists recorded the first signs of the presence of DMS back in 2023, but at that time they were not sufficiently conclusive. New measurements using the MIRI instrument confirmed that the spectrum of the atmosphere contains features that correspond to either DMS or DMDS. The two cannot be completely distinguished because they have similar chemical fingerprints. Scientists said that the concentration could reach up to 10 parts per million, which is much more than on Earth. However, this is not yet definitive evidence of life. Scientists emphasize that it is necessary to make further measurements and investigate other possible, non-living chemical processes. However, if the results are confirmed, it could be a revolutionary discovery in the search for life beyond Earth.
Very interesting.