The prospect of discovering alien life seems closer than ever. In 2025, a press release highlighted the âstrongest hints yetâ of extraterrestrial existence on the exoplanet K2-18b. Additionally, NASA Administrator Sean Duffy commented on a sample from a Martian rock called âCheyava Falls,â stating it was the âclosest we have ever comeâ to finding life on Mars.
These announcements capture the publicâs imagination but also prompt a critical question: what do most scientists believe about these findings?
Surprisingly, we often do not have a clear answer.
frameborder=â0âł allow=âaccelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-shareâ referrerpolicy=âstrict-origin-when-cross-originâ allowfullscreen>When scientific breakthroughs make headlines, journalists and press officers often refer to a select few experts. While these perspectives are valuable, they rarely provide a comprehensive view of the scientific communityâs consensus.
Public discussions frequently hinge on phrases like âthe science saysâ or âscientists believe,â suggesting a definitive viewpoint. However, systematic evidence of scientific opinion is often lacking. My colleagues and I sought to address this in astrobiology.
Following the two major 2025 announcements regarding potential extraterrestrial life, we surveyed astrobiologists to gauge the range of expert opinions.
The first case involved the exoplanet K2-18b. In April 2025, researchers identified possible traces of dimethyl sulfide and/or dimethyl disulfide, molecules linked to biological activity on Earth.
Media coverage portrayed this as a significant step forward in the search for alien life.
The second case emerged in September when NASA reported that the Cheyava Falls rock might contain a biosignature, known as âleopard spots,â which are mineral rings often formed by microbial activity on Earth.
NASA and media suggested this could be a groundbreaking discovery.
What Scientists Actually Thought
We surveyed hundreds of astrobiologists worldwide shortly after each announcement, asking if they believed extraterrestrial life had likely been discovered.
The survey results showed a cautious outlook. For K2-18b, only 6.6% of astrobiologists agreed that extraterrestrial life was probably found, while nearly two-thirds disagreed and 28.0% remained neutral.
In the Mars case, confidence was somewhat higher but still tentative: 15.1% agreed, 44.6% disagreed, and 40.3% were neutral.
Focusing solely on agreement and disagreement misses a key point.
The number of astrobiologists who strongly disagreed dropped significantly, from 35.1% in the K2-18b case to 11.1% regarding Mars.
frameborder=â0âł allow=âaccelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-shareâ referrerpolicy=âstrict-origin-when-cross-originâ allowfullscreen>This change was less about moving from rejection to endorsement and more about shifting from strong rejection to more tentative views.
In essence, expert opinion evolved in a structured manner. The shift from K2-18b to Mars was not a straightforward ânoâ to âyesâ transition. Rather, the community showed increased openness to the possibility without fully endorsing it.
One reason could be the differing nature of evidence in the two cases.
The K2-18b claim was based on potential atmospheric signatures detected over interstellar distances, while the Martian case involved a rock that could be directly studied in detail.
Astrobiologists are also aware that lifelike features can sometimes result from non-biological processes.
The challenge often lies not in imagining how life could create a signal, but in understanding how similar signals could arise without life.
Scientific opinion is rarely binary. Public discourse often treats science as a simple matter of agreement or disagreement.
Yet, the range of opinionsâwhether strong agreement, agreement, neutrality, disagreement, or strong disagreementâoffers insight into a scientific communityâs response to a claim.
A significant neutral response can imply several things: scientists may find the evidence inconclusive, hold a moderate level of confidence, or view the claim as too speculative to support or refute definitively.
Similarly, a shift from strong to ordinary disagreement might reflect a softening stance, even if overall disagreement remains high.
Presenting scientific opinion as merely âforâ or âagainstâ oversimplifies these nuanced perspectives.
Beyond Extraterrestrial Life
This lesson extends beyond the search for alien life. In fields like climate science, pandemics, artificial intelligence, or medical research, public debates often cite scientific consensus.
Sometimes, strong agreement truly exists; other times, it does not.
We often lack systematic methods to measure scientistsâ opinions, particularly when evidence is emerging or uncertainty is significant. Instead, discussions often rely on selective quotes, vocal individuals, or assumptions about community viewpoints.
Related: Alien Megastructures May Be Physically Feasible, a New Study Suggests
Efforts to gather systematic data are beginning to take shape.
At Durham University, our research group, C-Scope (the Centre for Scientific Community Opinion Polling and Evaluation), examines how expert opinions are distributed and how they evolve over time.
Our goal is not to replace evidence with polling or to equate majority opinion with truth. Instead, we aim to understand how scientific communities respond to uncertainty more thoroughly.
Scientific knowledge progresses through uncertainty, disagreement, and gradual refinement. As public discourse and potentially political action increasingly rely on what scientists think, more effort should be made to uncover these perspectives.
Peter Vickers, Professor in Philosophy of Science, Durham University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
