Scientists found a potential sign of life on a distant planet – an astronomer explains why many are still skeptical

Daniel Apai, Associate Dean for Research and Professor of Astronomy and Planetary Sciences, University of Arizona
A team of astronomers announced on April 16, 2025, that in the process of studying a planet around another star, they had found evidence for an unexpected atmospheric gas. On Earth, that gas – called dimethyl sulfide – is mostly produced by living organisms. In April 2024, the James Webb Space Telescope stared at the host star of the planet K2-18b for nearly six hours. During that time, the orbiting planet passed in front of the star. Starlight filtered through its atmosphere, carrying the...