A team of researchers has made a significant breakthrough in the search for extraterrestrial life, indicating the potential presence of biological processes outside our solar system. The findings concern K2-18b, a planet located 120 light-years away from Earth, which orbits within the habitable zone of its star, a region where conditions may allow for liquid water—essential for life as we know it.
Utilising the James Webb Space Telescope, the scientists identified two organic gases—dimethyl sulfide (DMS) and dimethyl disulfide (DMDS)—in the atmosphere of K2-18b. On Earth, these gases are produced primarily by marine microorganisms, particularly phytoplankton. While the discovery has excited the researchers, including lead author Nikku Madhusudhan from Cambridge University, they cautioned that the presence of these gases does not definitively confirm life. More observations are necessary to establish whether these gases result from biological processes or other non-biological sources.
Madhusudhan expressed that this groundbreaking research represents a “transformational moment” in the quest for extraterrestrial life, marking the dawn of observational astrobiology where identifying biosignatures from potentially habitable planets is now a possibility. He stressed that while these findings hint at the potential for life, the focus remains on understanding if such microbial life exists rather than speculating about more complex forms.
K2-18b is notable for being 8.6 times larger than Earth and lies within the so-called “Goldilocks zone,” where conditions might support liquid water, a crucial element for life. Since the 1990s, astronomers have discovered around 5,800 exoplanets outside our solar system, igniting discussions about the existence of Hycean worlds—planets that could be enveloped by vast oceans, likely inhabited by microbial life akin to that found in Earth’s oceans.
Addressing the prospect of discovering multicellular organisms or intelligent life, Madhusudhan stated that current assessments focus on simpler microbial life forms. The research not only opens the door to further investigations into the potential for life beyond Earth but also emphasises the need for continued observation and study of distant worlds.