James Webb Detects Biosignature Candidate on K2-18b

The James Webb Space Telescope's detection of a potential biosignature in the atmosphere of exoplanet K2-18b, located 120 light-years from Earth, was the most electrifying astronomical finding of 2025. Spectroscopic analysis suggested the presence of dimethyl sulfide, a compound produced on Earth only by biological processes. While scientists maintained appropriate scientific caution, the finding was widely described as the closest humanity had come to potential evidence of extraterrestrial life.