Strongest clues yet of alien life found on distant planet

Scientists using the James Webb Telescope have detected potential biosignatures, gases linked to life, on exoplanet K2-18 b, marking a major step in the search for extraterrestrial life. While not confirmed, the findings offer a strong "maybe".

In what could be a major step in the search for extraterrestrial life, scientists using the James Webb Space Telescope have detected chemical signatures in the atmosphere of exoplanet K2-18 b that may indicate biological activity. The gases, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) are, on Earth, only produced by living organisms, mainly marine microbes like phytoplankton. While not a confirmation of life, researchers consider this a promising biosignature that warrants cautious optimism.

Astrophysicist Nikku Madhusudhan from the University of Cambridge, lead author of the study published in Astrophysical Journal Letters, called it a groundbreaking moment. He said the findings suggest it's now possible to detect signs of life on habitable planets using existing tools, marking the beginning of a new era in astrobiology.

K2-18 b is located about 124 light-years away in the Leo constellation, orbiting a small red dwarf star in the "habitable zone" where liquid water could exist. The planet is roughly 8.6 times the mass of Earth and is believed to be a "hycean world", possibly covered by oceans and with a hydrogen-rich atmosphere, ideal for microbial life.

Previous Webb observations found methane and carbon dioxide on the planet. Now, using different instruments and wavelengths, scientists have identified DMS or DMDS with 99.7% confidence, concentrations thousands of times higher than on Earth, which cannot easily be explained by non-biological processes.

Though researchers are excited, they emphasize that more observations and theoretical studies are necessary to rule out non-living chemical sources. Confirming these findings will require repeated measurements and rigorous testing.

Experts not involved in the study agree the data is compelling but urge careful validation. The long-standing question of whether we are alone in the universe may be closer to an answer, but for now, the evidence remains a strong "maybe".