WASHINGTON — In what could be a groundbreaking discovery, scientists using the James Webb Space Telescope (JWST) have detected the strongest indicators so far of possible life beyond our solar system. They found chemical traces in the atmosphere of a distant planet — K2-18 b — that, on Earth, are produced solely by living organisms. The gases — dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) — are typically released by marine microbes like phytoplankton. Their presence suggests K2-18 b may host microbial life. However, researchers emphasize that this is not direct evidence of living organisms, but rather a potential biosignature, or sign of life-related chemical activity. More observations are needed to confirm the findings.

Astrophysicist Nikku Madhusudhan from the University of Cambridge, the study’s lead author, expressed excitement, calling it a major step forward in the search for extraterrestrial life. He noted this marks the first time that biosignatures have potentially been identified on a habitable exoplanet using current telescope technology — a significant milestone for observational astrobiology. While previous missions have investigated Mars, Venus, and icy moons for signs of life, this finding looks far beyond — at a planet 124 light-years away in the constellation Leo. K2-18 b, 8.6 times more massive than Earth and 2.6 times its diameter, orbits a red dwarf star in its habitable zone, where liquid water could exist — a key ingredient for life.

The planet is thought to be a hycean world — a theorized type of exoplanet with a hydrogen-rich atmosphere and a warm, deep ocean possibly suited for microbial life. Earlier JWST data had already found carbon-based molecules like methane and carbon dioxide in K2-18 b’s atmosphere. Now, the detection of DMS or DMDS at over 10 parts per million — levels much higher than on Earth — strongly hints at biological activity, as no known non-biological processes explain their presence in such quantities. Madhusudhan noted that while this strengthens the case for life, scientists need to remain cautious. The detection, though statistically significant (99.7% confidence), still leaves a 0.3% chance it could be a statistical anomaly. Repeat observations and deeper theoretical analysis are necessary to rule out non-biological sources for these gases.

Other experts welcomed the findings but echoed the call for careful verification. Christopher Glein of the Southwest Research Institute described the planet as "tantalizing" but emphasized the need for rigorous testing and independent confirmation. K2-18 b belongs to the sub-Neptune category — planets larger than Earth but smaller than Neptune. To study its atmosphere, astronomers use the transit method, analyzing starlight that passes through the planet’s atmosphere as it moves in front of its host star.

The JWST’s newer instrument and wavelength range offered more detailed results compared to previous data. Still, Madhusudhan underlined that science must avoid prematurely declaring the discovery of life. Though we may be on the brink of answering humanity’s age-old question — “Are we alone?” — researchers must first confirm the biosignatures through repeated observations and explore every alternative explanation. In conclusion, while the evidence from K2-18 b is compelling and could mark the dawn of a new chapter in the search for life, it remains a hopeful possibility, not a confirmed reality — at least, not yet.

Disclaimer: This image is taken from Reuters.