At a distance of 124 light-years, the James Webb Space Telescope offered humanity its most intimate glimpse yet of a world that might harbor oceans — and in doing so, revealed how vast the distance remains between detecting a molecule and understanding its meaning. Faint spectral hints of dimethyl sulphide on the exoplanet K2-18 b briefly suggested the chemical signature of life, but independent teams found the signals dissolved under scrutiny, replaced by equally plausible abiotic explanations. The episode is less a disappointment than a clarification: the search for life beyond Earth demands