A groundbreaking discovery led by Indian-origin astrophysicist Professor Nikku Madhusudhan has revealed the strongest evidence yet of possible alien life on a planet outside our solar system.

Using data from NASA’s James Webb Space Telescope (JWST), Madhusudhan and his team at the University of Cambridge detected chemical signatures in the atmosphere of exoplanet K2-18b, located 124 light-years away in the constellation Leo.

Specifically, the team identified traces of dimethyl sulphide (DMS) and dimethyl disulfide (DMDS) — molecules known on Earth to be exclusively produced by living organisms, primarily marine microbes like phytoplankton. Both chemicals are considered potential biosignatures, indicators of life.

“The signal came through strong and clear,” said Madhusudhan, describing the findings as “exciting” and potentially historic. While natural, non-biological explanations for the molecules haven’t been ruled out, he noted this is the most compelling hint of extraterrestrial life to date.

The discovery builds on earlier data collected using JWST’s near-infrared instruments. This time, researchers used the telescope’s mid-infrared instrument (MIRI), which confirmed the presence of DMS and DMDS at far higher concentrations than found on Earth — up to 10 parts per million compared to less than 1 part per billion here.

The results achieved a statistical significance of three-sigma, meaning there’s only a 0.3% chance the findings are random. To be considered a confirmed scientific discovery, however, a five-sigma threshold (0.00006% chance) must be met. Researchers say 16 to 24 hours of additional observation time could help them get there.

“This could be the tipping point — where we’re finally close to answering the age-old question: Are we alone in the universe?” said Madhusudhan. Still, he emphasized the need for more data before making any definitive claims about alien life.

JWST is an international mission led by NASA, in collaboration with the European Space Agency and the Canadian Space Agency.