James Webb Telescope Detects Potential Signs of Life on Distant Planet

A planet orbiting a distant star 120 light-years from Earth has shown the strongest signs yet of potential extraterrestrial life, according to new observations from the James Webb Space Telescope.

Astronomers have detected the chemical signatures of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the atmosphere of K2-18 b, a Neptune-sized planet located in the habitable zone of a red dwarf star in the constellation Leo. On Earth, both compounds are predominantly produced by marine organisms.

“This is the strongest evidence to date for biological activity beyond the solar system,” said Prof. Nikku Madhusudhan, an astrophysicist at the University of Cambridge who led the research. “We are very cautious. We have to question whether the signal is real and what it means.”

The findings, published in The Astrophysical Journal Letters, stop short of confirming alien life but bring scientists closer to answering one of humanity’s oldest questions: Are we alone in the universe?

The chemicals were detected as the planet passed in front of its host star, allowing researchers to analyze starlight filtered through its atmosphere. The data revealed a sharp drop in light at wavelengths absorbed by DMS and DMDS—molecules previously found only in biological processes on Earth.

“The signal came through strong and clear,” Madhusudhan said. “It’s mind-boggling that this is possible.”

The chemical concentrations detected were thousands of times higher than those found on Earth. However, the results reached only a “three-sigma” statistical confidence level, meaning there’s still a 0.3% chance the findings were random.

Some scientists remain skeptical, noting that other non-biological processes could potentially produce the compounds. “Life is one of the options, but it’s one among many,” said Dr. Nora Hänni, a chemist at the University of Berne, who found DMS on a lifeless comet.

Others caution that conditions on K2-18 b are still poorly understood. While Madhusudhan’s team suggests the planet could host a vast ocean, other models propose it may be a gas giant or covered in magma.

Despite the uncertainty, the detection marks a major step forward in exoplanet research. “We’re trying to establish if the laws of biology are universal,” Madhusudhan said. “In astronomy, the question is never about going there.”