Using data from the James Webb Space Telescope (JWST), the astronomers, led by the University of Cambridge, have identified the chemical fingerprints dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) – molecules that indicate life. Here on Earth, these molecules are only produced by living organisms – primarily microbial life such as marine phytoplankton. The molecules have been detected in the atmosphere of exoplanet K2-18b, which is located around 124 light-years from Earth in the constellation of Leo.