Survey of Astrobiologists Finds Most Remain Cautious About 2025's Alien-Life Claims

A survey of hundreds of astrobiologists has found that most experts remained cautious rather than convinced following two widely publicized 2025 claims about possible signs of extraterrestrial life, according to research from a group at Durham University. Researchers surveyed the scientists within days of each announcement, asking a simple question: did they think extraterrestrial life had probably been found.

The first case involved the exoplanet K2-18b, where researchers reported in April 2025 possible traces of dimethyl sulfide and dimethyl disulfide, molecules associated with biological activity on Earth, and an official statement described the finding as the "strongest hints yet" of alien life. Only 6.6% of surveyed astrobiologists agreed that scientists had probably found extraterrestrial life in that case, while nearly two-thirds disagreed and 28.0% remained neutral.

The second case came in September 2025, when NASA announced that a Mars rock sample called Cheyava Falls appeared to preserve "leopard spot" mineral rings, a pattern that on Earth is often formed by microbial activity; NASA Administrator Sean Duffy called it the "closest we have ever come" to finding life on the planet. For this case, 15.1% of astrobiologists agreed extraterrestrial life had probably been found, 44.6% disagreed, and 40.3% were neutral.

The share of astrobiologists who strongly disagreed fell sharply, from 35.1% for K2-18b to 11.1% for Mars, suggesting the shift was less a move toward acceptance and more a softening from strong rejection to tentative rejection. The researchers, who run a group called C-Scope, the Centre for Scientific Community Opinion Polling and Evaluation, say they aim to measure how scientific opinion is distributed and changes over time, rather than replace evidence with polling or treat majority views as truth.