Astronomers operating the James Webb Space Telescope have identified dimethyl sulfide in the atmosphere of exoplanet K2-18b, a molecule produced by living organisms on Earth. The finding strengthens earlier suggestions that this Hycean planet, orbiting a cool red dwarf star, may possess liquid-water oceans beneath a hydrogen-rich sky.

Scientists from NASA and ESA caution that the detection remains tentative and requires additional telescope time to rule out non-biological sources. Nevertheless, the presence of this compound marks one of the most intriguing chemical clues yet uncovered beyond our solar system.

Future observation campaigns will target other potential biomarkers and refine measurements of the planet’s temperature and cloud properties. Researchers hope these data will clarify whether biological activity offers the best explanation for the observed chemistry.