Have we found alien life? Hundreds of scientists gave their verdict
What happened
In 2025 there were two big announcements that sounded, to a lot of people, like the discovery of life beyond Earth. The first came in April 2025. A team using the James Webb Space Telescope reported possible traces of molecules in the atmosphere of a distant planet called K2-18b. On Earth, those molecules are mostly made by living things, especially sea life. The second came later that year. NASA reported possible signs of past biological activity in a Martian rock nicknamed Cheyava Falls. Rather than argue about it in press releases, a team of researchers did something unusual. They asked the scientists. Led by Peter Vickers, a professor in the philosophy of science at Durham University, they surveyed hundreds of astrobiologists shortly after both announcements. The results were published in the journal Nature Astronomy and reported on 9 September 2026.
Why this matters
"Scientists say" is one of the most overused phrases in news reporting. It usually means one or two scientists said something quotable. This survey is different, and that is why it is interesting. Instead of picking a few voices, it measured what a whole research community actually thinks. That is a much fairer picture of where the evidence stands. It also shows something useful about how science works. Being cautious is not the same as being negative. The researchers who made the original K2-18b announcement did not claim they had found life. They reported a signal that might, or might not, have a biological explanation. The gap between that and the headlines was enormous. If you have ever wondered how seriously to take a dramatic science story, this survey is a good worked example.
What the evidence actually says
For K2-18b, the numbers were clear. Only 6.6% of the astrobiologists surveyed agreed that life had probably been found. 65.4% disagreed. 28.0% sat in the middle, neither agreeing nor disagreeing. For the Mars rock, the mood was different. 15.1% agreed that life had probably been found, 44.6% disagreed and 40.3% were neutral. The most telling number is the strength of the disagreement. Strong disagreement fell from 35.1% for K2-18b to 11.1% for the Mars rock. So on Mars, the community was more open to the possibility without actually being convinced. That pattern makes sense. A rock on Mars can, in principle, be examined directly and even brought home. A planet 124 light years away can only be studied by reading the light that passes through its atmosphere, which is a much harder thing to interpret. A separate NASA-led reanalysis has since found no conclusive evidence for those molecules on K2-18b, while confirming that the planet is water-rich and has a complex atmosphere. Neither result rules anything out. Both say the same thing: not proven.
Practical advice
You can use the same three questions on any big science headline you read. First, ask what was actually measured. "Possible traces of a molecule" is a very different claim from "life detected". The measurement is usually buried a few paragraphs down. Second, ask who else has looked. One team with one instrument is a starting point. A result becomes solid when other groups, using other methods, get the same answer. Third, ask what would change the answer. Good researchers can tell you exactly what evidence would prove them wrong. Be wary when nobody can. It is also worth noticing your own reaction. Stories about alien life are exciting, and excitement makes all of us less careful readers. A short pause before sharing is usually enough. None of this means being cynical. The K2-18b work is genuinely good science. It just has not finished yet.
What to know
Researchers led by Durham University surveyed hundreds of astrobiologists about the two 2025 announcements that seemed to hint at life beyond Earth. For the exoplanet K2-18b, 6.6% thought life had probably been found and 65.4% disagreed. For the Martian rock Cheyava Falls, 15.1% agreed and 44.6% disagreed, with far less strong disagreement than for K2-18b. The community is interested and open, not convinced. That is the honest state of play, and the findings were published in Nature Astronomy. Sources: ScienceDaily, "Have we found alien life? Hundreds of scientists weigh in", 9 September 2026, https://www.sciencedaily.com/releases/2026/09/260909005212.htm | Astronomy.com, "Signs of life on K2-18 b revisited in new NASA study", 2026, https://www.astronomy.com/science/new-study-revisits-signs-of-life-on-k2-18-b/ | EurekAlert (AAAS), "Strongest hints yet of biological activity outside the solar system", April 2025, https://www.eurekalert.org/news-releases/1080558 This article is for general information. It covers scientific research and is not health advice, and it does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
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