A research team at the University of Cambridge has uncovered tantalising evidence that life may exist on a distant planet named K2-18b, located 124 light years away in the Leo constellation.
Using the powerful James Webb Space Telescope (JWST), scientists detected molecules in the planet’s atmosphere that, on Earth, are only produced by living organisms.
Leading the investigation is Professor Nikku Madhusudhan of Cambridge’s Institute of Astronomy, who described the findings as “the strongest evidence yet” that life might be present beyond Earth. The team identified chemical signatures of dimethyl sulphide (DMS) and dimethyl disulphide (DMDS)—gases typically emitted by plankton and bacteria in Earth’s oceans.
“The amount of gas we estimate is thousands of times more than on Earth,” said Prof Madhusudhan speaking to the BBC.
“If the link with life holds, K2-18b could be teeming with it.”
A Long Road to Confirmation
While the findings have sparked excitement, astronomers caution that more data is needed. The current analysis has a confidence level of 99.7%, well short of the 99.99999% required to claim a scientific discovery. Yet, the result is far stronger than an earlier reading made 18 months ago, which had only 68% certainty.
Even with more precise measurements, questions will remain. “Even perfect data won’t guarantee that the gas is from life,” said Professor Catherine Heymans, Scotland’s Astronomer Royal. Geological or other unknown planetary processes could potentially produce similar gases.
Alternative theories about K2-18b’s composition also muddy the waters. Some researchers suggest it might be an ocean planet; others argue it could be a rocky world or even a mini gas giant. Still, the debate underscores how far astronomy has come—and how close we may be to answering one of humanity’s oldest questions.
“Decades from now, we may look back and say this was the moment the living universe came into view,” said Prof Madhusudhan.
