Life On An Alien Planet? Scientists Find Strongest Evidence

Image credit: Freepik

Scientists using the James Webb Space Telescope have made what they describe as the most compelling detection so far of potential life beyond our solar system. They found chemical traces in the atmosphere of a distant exoplanet, K2-18 b, that on Earth are known to be produced solely by living organisms.

The specific compounds—dimethyl sulfide (DMS) and dimethyl disulfide (DMDS)—were observed in the planet’s atmosphere. On Earth, these gases are primarily generated by microbial life, particularly marine phytoplankton like algae. Their presence on K2-18 b could indicate similar microbial activity.

However, researchers stress that this is not direct evidence of life. Instead, it's a possible biosignature—a clue pointing to biological processes. While the findings are exciting, scientists caution that further observations are needed to confirm them.

Astrophysicist Nikku Madhusudhan from the University of Cambridge, who led the study, emphasized the potential importance of this discovery. He noted that this marks a major milestone in astrobiology—showing that it’s now possible to detect potential signs of life on distant, habitable planets using current technology.

K2-18 b, located about 124 light-years away in the constellation Leo, is categorized as a "hycean world"—a type of exoplanet theorized to have oceans beneath hydrogen-rich atmospheres that could support microbial life. The planet is about 8.6 times more massive than Earth and 2.6 times its diameter. It orbits in the star’s habitable zone, where liquid water could exist.

Previous Webb data had shown the presence of carbon-based molecules like methane and carbon dioxide. The detection of DMS and DMDS at concentrations significantly higher than those on Earth strengthens the hypothesis that life could exist there—though other explanations haven’t been ruled out.

Madhusudhan and other researchers underscore the importance of repeated observations and further theoretical and experimental work to rule out non-biological sources for these gases.

Ultimately, while the findings represent a promising step, scientists are being careful not to jump to conclusions. As Madhusudhan put it, while this could be the start of answering the age-old question—"Are we alone?"—it’s still too early to say for sure.