New Delhi— A groundbreaking study led by Indian-origin astrophysicist Professor Nikku Madhusudhan has uncovered the strongest indications to date of potential alien life on an exoplanet located more than 120 light-years from Earth. The findings, published Thursday in The Astrophysical Journal Letters, stem from observations made using NASA’s James Webb Space Telescope (JWST).
Professor Madhusudhan, from the University of Cambridge’s Institute of Astronomy, called the signals “exciting,” noting that “the signal came through strong and clear.” His team detected the chemical signatures of dimethyl sulfide (DMS) and/or dimethyl disulfide (DMDS) in the atmosphere of K2-18b, a planet located in the constellation Leo.
K2-18b is about 8.6 times more massive and 2.6 times larger than Earth. Both DMS and DMDS are considered potential biosignatures—molecules associated with life. On Earth, they are exclusively produced by living organisms, primarily marine phytoplankton.
While the presence of these molecules could theoretically result from unknown chemical processes, the researchers say the findings represent the most compelling evidence yet that life may exist beyond our solar system.
“We didn’t know for sure whether the signal we saw last time was due to DMS, but just the hint of it was exciting enough for us to take another look with JWST using a different instrument,” Madhusudhan said.
Initial indications of DMS came from JWST’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) and Near-Infrared Spectrograph (NIRSpec), which scan light in the 0.8 to 5 micron range. The new observations used JWST’s Mid-Infrared Instrument (MIRI), which operates in the 6 to 12 micron range—providing independent confirmation of the earlier findings.
The latest data reached the “three-sigma” level of statistical significance, meaning there’s only a 0.3% chance the signals were detected by coincidence. For a finding to be classified as a scientific discovery, it must reach five-sigma significance—indicating a probability of less than 0.00006% of the result occurring by chance.
According to the researchers, an additional 16 to 24 hours of JWST observation time could help reach that critical threshold.
The study also revealed that concentrations of DMS and DMDS on K2-18b are vastly higher than on Earth. While Earth’s atmospheric levels are below one part per billion, the exoplanet may host levels exceeding 10 parts per million—thousands of times stronger.
“This could be the tipping point,” Madhusudhan said. “We may finally be close to answering the fundamental question: Are we alone in the universe?”
However, he emphasized the need for caution and further study. “While the results are exciting, it’s vital to obtain more data before claiming that life has been found on another world.”
The James Webb Space Telescope is a joint mission led by NASA, with support from the European Space Agency (ESA) and the Canadian Space Agency. (Source: IANS)
