New Delhi, April 17 (NationPress) A study led by an Indian-origin astrophysicist, published on Thursday, has unveiled the most compelling evidence of alien life to date on an exoplanet located over 120 light-years from Earth.

Referring to the findings as "exciting," Professor Nikku Madhusudhan from the University of Cambridge’s Institute of Astronomy in the UK stated that "the signal was both strong and clear."

Utilizing data from the next-generation James Webb Space Telescope (JWST), Madhusudhan and his team identified the chemical signatures of dimethyl sulphide (DMS) and/or dimethyl disulfide (DMDS) in the atmosphere of the exoplanet K2-18b.

K2-18b is approximately 8.6 times more massive and 2.6 times larger than Earth, situated 124 light-years away in the constellation of Leo.

DMS and DMDS belong to the same chemical family, with both expected to serve as biosignatures.

On our planet, these compounds are exclusively produced by life, predominantly by microorganisms like marine phytoplankton.

Although an unknown chemical process could account for these molecules in the atmosphere of K2-18b, the results represent the strongest evidence to date suggesting the potential existence of life beyond our solar system, according to the team in their paper published in The Astrophysical Journal Letters.

“We were uncertain if the signal detected previously was due to DMS, but the mere indication was intriguing enough to warrant a second look with JWST employing a different instrument,” said Professor Madhusudhan, who spearheaded the research.

The initial, tentative detection of DMS was made using JWST’s NIRISS (Near-Infrared Imager and Slitless Spectrograph) and NIRSpec (Near-Infrared Spectrograph) instruments, which collectively cover the near-infrared (0.8-5 micron) spectrum. The recent, independent observation utilized JWST’s MIRI (Mid-Infrared Instrument) in the mid-infrared (6-12 micron) range.

Significantly, the latest observations achieved a ‘three-sigma’ level of statistical significance—indicating a 0.3 percent probability that these results occurred by chance.

For these observations to be classified as a scientific discovery, they would need to surpass the five-sigma threshold, implying a probability of less than 0.00006 percent that they resulted from random chance.

The researchers mentioned that 16 to 24 hours of additional observation time with JWST might allow them to reach the critical five-sigma significance.

The study indicated that the concentrations of DMS and DMDS in K2-18b's atmosphere are substantially greater than those on Earth. While the levels on Earth are below one part per billion by volume, they are estimated to be thousands of times higher—exceeding ten parts per million—on K2-18b.

“This could represent a pivotal moment, wherein we might finally answer the fundamental question of whether we are alone in the universe.”

“While these findings are thrilling, it is essential to gather more data before asserting that life has been discovered on another planet,” Madhusudhan emphasized.

The James Webb initiative is an international program led by NASA in collaboration with its partners, ESA (European Space Agency) and the Canadian Space Agency.