First Study Suggests Organic Life May Exist on Distant Planet

The first study to confirm the potential for organic life on a distant planet in the Leo constellation. Using the James Webb Space Telescope, scientists have detected two specific gases in the planet’s atmosphere that, on Earth, are produced exclusively by marine algae. However, the presence of biological activity remains a hypothesis.

The study, published in Astrophysical Journal Letters, revealed that the atmosphere of the planet K2-18 b—located approximately 124 light-years from Earth in the constellation Leo—contains dimethyl sulfide (DMS) and dimethyl disulfide (DMDS). These two gases are also present in Earth’s atmosphere, but here they are produced exclusively by living organisms, particularly marine phytoplankton and other algae-like microorganisms. The researchers emphasized that they did not detect life itself, but rather a chemical signature suggestive of it—pointing to the potential presence of organic processes. Further observations are needed to confirm the findings.

Although scientists remain cautious, acknowledging that these chemicals could potentially be formed through unknown, non-biological processes in alien environments, the discovery currently stands as the most compelling, scientifically supported hypothesis for the possible existence of an inhabited extraterrestrial world.

“This is a pivotal moment in the search for life beyond our solar system,” said astrophysicist Nikku Madhusudhan of the University of Cambridge’s Institute of Astronomy, lead author of the study. “We’ve shown that it is possible to detect biosignatures on potentially habitable planets using current instruments. We are now in the era of observational astrobiology.”

Exoplanet K2-18 b is about 8.6 times more massive than Earth and roughly 2.6 times its diameter, orbiting at an estimated distance of 1.1 quadrillion kilometers from our planet.

Since the 1990s, when scientists first developed techniques to detect exoplanets—which, lacking their own light, are observed as shadows passing in front of stars—there has been speculation about the existence of so-called “Hycean worlds”: ocean-covered planets with hydrogen-rich atmospheres, believed to be strong candidates for harboring organic life. Previous observations by the James Webb Space Telescope—launched in 2021 and operational since 2022—have already detected methane and carbon dioxide in the atmosphere of K2-18 b.