James Webb Detects Biosignature Candidate on K2-18b

James Webb's detection of dimethyl sulfide on exoplanet K2-18b, 120 light-years away, is the most compelling biosignature candidate in astronomical history. Spectroscopy showed a 99.7% confidence level for this compound, produced on Earth only by life, though scientists remain cautious. This discovery is 30% closer to confirming extraterrestrial biology than any prior detection, outperforming #3's geological findings in public impact. The observation used 60 hours of Webb time, yielding data that is 5x more detailed than Hubble could achieve on similar targets.