K2-18b
A planet 124 light-years away where the James Webb Space Telescope saw methane and carbon dioxide, and where one team reports a possible sign of life.
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K2-18b and the 2025 'Strongest Hints' of Life
K2-18b is a sub-Neptune planet about 124 light-years away. In April 2025 Nikku Madhusudhan's Cambridge team reported three-sigma evidence from the James Webb Space Telescope for dimethyl sulfide in its atmosphere, a gas made on Earth by life. This article sets out the planet, the signal, the other teams' reanalyses and what is still open.