The world, the universe and us Weekly: Have we really just found the strongest evidence for alien life yet?
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Apr 17, 2025 
Join Alex Wilkins, a science communicator with a knack for making complex topics accessible, as he delves into groundbreaking claims about alien life. The discussion centers around the detection of dimethyl sulfide (DMS) on the exoplanet K2-18b, a potential biosignature indicating life. While excitement mounts, they explore the complexities of confirming these findings and the hurdles astronomers face in the vast universe. Skepticism and hopes collide as they assess what this discovery truly means for our understanding of extraterrestrial life.
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Possible Biosignature Detected
- Astronomers detected dimethyl sulfide (DMS) in the atmosphere of exoplanet K2-18b, a molecule on Earth produced only by life.
- This detection could be the first evidence of possible biological activity beyond Earth but requires cautious interpretation.
Detection Needs Higher Confidence
- The statistical confidence of this detection is around three sigma, meaning a 99.7% chance it's real but not definitive.
- Scientists regard five sigma as gold standard, so more observations are needed to confirm the finding.
DMS May Not Be Biosignature
- Even if DMS is confirmed, it may not necessarily be a biosignature since unknown abiotic processes might also produce it.
- Extraordinary claims like discovering alien life require extraordinary evidence, which is not yet present.