K2-18 b: The Planet That Shows How Close We Are to the Edge of Knowing

K2-18 b is not proof of alien life, but it may be one of the most important exoplanets ever studied because it shows how the search for life is shifting from imagination to contested atmospheric chemistry. JWST has detected methane and carbon dioxide in its atmosphere, while disputed DMS and DMDS claims show how difficult it will be to separate biology, chemistry, instrument noise, media hype, and human hope.