Potential Biosignature on Exoplanet K2-18b Raises Hopes of Extraterrestrial Life

Astronomers have potentially identified biosignature molecules on exoplanet K2-18b, raising hopes for extraterrestrial life. Using the James Webb Space Telescope, researchers found dimethyl sulfide and dimethyl disulfide, known life-related compounds on Earth, in the planet's atmosphere. Further observations are needed to confirm the discovery.

Astronomers have possibly identified signs of life on a planet beyond our solar system. Led by the University of Cambridge, a team utilized the James Webb Space Telescope to detect chemical traces of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the atmosphere of exoplanet K2-18b, which resides in its star's habitable zone.

On Earth, DMS and DMDS are predominantly produced by microbial life like marine phytoplankton. Although an unknown process could be responsible for these molecules on K2-18b, the findings mark the strongest evidence to date that life might exist on a planet outside our solar system. The observations reached a 'three-sigma' statistical significance, indicating a 0.3% probability of mere chance occurrence.

Achieving the 'five-sigma' mark, which denotes less than a 0.00006% probability of chance, is necessary for scientific recognition. Researchers indicate that additional observations, up to 24 hours using JWST, might provide definitive confirmation. Their findings, published in The Astrophysical Journal Letters, build upon earlier data revealing methane and carbon dioxide on K2-18b, consistent with predictions of a 'Hycean' planet—a potentially habitable world with an ocean beneath a hydrogen-rich atmosphere.

(With inputs from agencies.)