In a significant development in the search for extraterrestrial life, scientists have identified molecules linked to biological activity in the atmosphere of exoplanet K2-18b, situated approximately 124 light-years away from Earth. The discovery was made possible through the advanced capabilities of NASA’s James Webb Space Telescope (JWST).
The research team detected the presence of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) — compounds that, on Earth, are predominantly produced by marine organisms like phytoplankton and certain types of bacteria. The detection of these exoplanet K2-18b molecules marks one of the most compelling indicators yet of the possibility of alien life beyond our solar system.
Earlier observations in September 2023 had already indicated that K2-18b possessed a hydrogen-rich atmosphere containing water vapor. In addition, the presence of carbon-based molecules, including methane and carbon dioxide, has further bolstered speculation about the planet’s habitability. Weighing in at 8.6 times the mass of Earth, K2-18b is located in the Leo constellation and falls under a category of planets known as “Hycean worlds” — planets believed to harbor vast oceans beneath hydrogen-rich atmospheres.
Despite the promising findings, scientists urge caution. Professor Nikku Madhusudhan from the University of Cambridge, who is leading the research, emphasized that further investigations are necessary to confirm the biological origin of the detected molecules. The team is also considering alternative, non-biological explanations for the presence of DMS and DMDS.
The next phase of research will involve a deeper analysis of K2-18b’s atmosphere to better understand its chemical composition and potential to support life. The James Webb Space Telescope’s sophisticated instruments are expected to play a crucial role in gathering more precise data in the coming months.
The discovery not only strengthens the hypothesis that life-supporting conditions may exist beyond Earth but also underscores the importance of Hycean worlds as promising candidates in the ongoing search for extraterrestrial life.
