Astrobiologist Poll Finds Just 6.6% Accept K2-18b Life Claim as Probable

The poll was fielded within days of each 2025 announcement, capturing opinion before media cycles hardened. Researchers asked respondents to rate agreement that extraterrestrial life had probably been found, producing a five-point distribution rather than binary yes/no. Results showed structured movement: strong disagreement fell from 35.1% for K2-18b to 11.1% for Mars, with most shift toward neutrality rather than endorsement.

Evidence type appears decisive. Remote atmospheric spectroscopy for the exoplanet faces greater abiotic ambiguity than the directly examinable Martian rock textures. The survey underscores that astrobiologists weigh both signal strength and the completeness of known non-biological pathways, not merely headline potential. This distribution of expert judgment rarely appears in press coverage that relies on a few quoted voices.

Mars sample return offers the clearest near-term test. Laboratory analysis of returned material could resolve whether the leopard-spot features require biology, potentially moving the community further from rejection. Systematic polling of this kind may become standard for high-profile claims to anchor public discussion in measured field consensus rather than selective quotation.