Dimethyl Sulfide on K2-18b: Biosignature Prospects and the Hard Steps Debate

To the point

New JWST observations raise the possibility that dimethyl sulfide, a gas produced by some Earth microbes, is present in K2-18b’s atmosphere, a potential sign of life but not proof since abiotic processes could also produce it, fueling a long-running debate over how common life is and whether its emergence hinges on a rare sequence of events like Brandon Carter’s hard steps or on environmental timing, while scientists caution against overinterpreting a single gas and historical echoes from Huygens and Wells remind us of the tug between sensational claims and sober skepticism.