Scientists Detect Possible Signs of Life on Distant Planet

A team from Cambridge, studying the atmosphere of the planet K2-18b, has identified traces of molecules that, on Earth, are produced solely by the simplest forms of life. The discovery was reported by the BBC.

The study’s lead, Professor Nikku Madhusudhan, described the findings as “the most compelling evidence to date that life in the universe might exist.” Researchers expect to confirm their data within the next one to two years.

K2-18b, a planet two and a half times larger than Earth, lies approximately 700 trillion miles away—about 119 light-years from us. Scientists detected chemical signatures in its atmosphere of at least one of two life-related molecules: dimethylsulfide (DMS) or dimethyldisulfide (DMDS). On our planet, these gases are generated by marine phytoplankton and bacteria.

Notably, the concentration of these gases, which the team believes may result from the activity of simple microorganisms, is estimated to be thousands of times higher in K2-18b’s atmosphere than on Earth. “If this link to life holds true, then this planet might be teeming with life,” Madhusudhan remarked.

However, the researchers caution that many uncertainties remain. Currently, they are 99.7% confident of the gas’s presence on K2-18b, but a scientific discovery requires a certainty of 99.99999%. Even if they achieve that threshold, the origin of the gas would still be in question.

“On Earth, these molecules are produced by ocean microorganisms, but even with perfect data, we can’t definitively say they have a biological origin on an alien planet. The universe is full of strange phenomena, and we don’t yet know what other geological processes on this planet might be producing these molecules,” said astronomer Katherine Heymans from the University of Edinburgh.