New Delhi: In a groundbreaking development, NASA’s James Webb Space Telescope (JWST) has detected molecules on the exoplanet K2-18b that are closely linked to life as we know it—marking one of the most compelling hints yet of extraterrestrial existence.
Biosignature gases observed in atmosphere
Astronomers have observed traces of two sulphur-bearing gases—dimethyl sulfide (DMS) and dimethyl disulfide (DMDS)—in K2-18b’s atmosphere. On Earth, these gases are largely produced by marine organisms such as bacteria and phytoplankton, making their presence particularly intriguing.
K2-18b: A Hycean world with ocean and hydrogen-rich envelope
K2-18b is a so-called Hycean planet—a world characterised by a watery ocean beneath a hydrogen-dominated atmosphere, located some 120–124 light-years away. These conditions hold major promise for habitability and have positioned the planet as a leading candidate in the search for alien life.
Strongest evidence yet, with cautious optimism
Scientists describe the discovery as the “strongest evidence yet” for possible life beyond Earth, with some estimating a 99.7% probability that the detected molecules are biogenic in origin. However, experts emphasise that a single biosignature is insufficient to confirm life—abiotic processes could also generate these gases, underscoring the need for further validation.
Scientific response: cautious excitement
The scientific community is cautiously excited, recognising this as a major step forward in astrobiology. Researchers call for additional observations—both theoretical and experimental—to rule out non-biological sources and strengthen the case for extraterrestrial life.
Why this matters
Detecting DMS and DMDS on K2-18b may signal microbial life in an alien ocean—a discovery that would revolutionise our understanding of life in the universe. It opens new frontiers in exoplanet research and highlights the JWST’s unprecedented power to probe distant worlds for biological clues.