In September 2023, headlines around the globe exploded with an electrifying claim: NASA’s James Webb Space Telescope might have found a “tantalizing sign of possible life on a faraway world” on K2-18b, an exoplanet located 120 light-years away in the constellation Leo.
Behind the excitement was a far more tentative reality. The signal was weak, the data preliminary, and the evidence highly speculative. Subsequent analysis data failed to find statistically strong support for the presence of biosignature gases in the planet’s atmosphere, casting serious doubt that K2-18b was harboring alien life.
Now, in a new study published in PLOS ONE, researchers systematically examined how claims about extraterrestrial life are communicated across the scientific ecosystem, tracing their evolution from peer-reviewed papers to institutional press releases and mainstream news coverage.
The findings reveal that while scientific papers rarely speculate or overpromise, the same cannot be said for the media coverage that follows.
“Our goal was to understand how research results from astrobiology are being portrayed in the public sphere,” the authors explain in the study. “We consider the study at least partially successful in this regard by uncovering the most frequent kinds of speculations and promises/expectations about the [search for life elsewhere] being communicated with the public, and how they occurred in different kinds of documents”.
From Caution to Sensation
Researchers from Leiden University and the Earth-Life Science Institute in Tokyo analyzed 630 documents spanning nearly three decades. This included 272 newspaper articles, 188 peer-reviewed papers, and 170 press releases—all focused on the hunt for alien life or the “Search for Life Elsewhere” (SLE), a subfield of astrobiology that examines whether and where life might exist beyond Earth.
The findings reveal that scientific papers tend to avoid dramatic claims, while press releases and media coverage often do not.
For instance, only 3.1% of academic papers speculated on whether research findings constituted “evidence of extraterrestrial life.” That figure rose to 5.8% in news articles—nearly double. Similarly, only 5.3% of papers speculated on the broader significance of a finding to SLE, compared to 28.2% of press releases and 23.9% of news articles.
The most striking difference came in coverage of “conditions for life,” such as the presence of water or specific biosignatures on distant worlds. While 22.8% of scientific papers mentioned such conditions speculatively, that number jumped to 47.6% in press releases and 56.6% in news articles.
It’s important to note that the researchers focused on six major legacy newspapers widely regarded as reputable sources of information, including The New York Times, The Guardian, Folha de S. Paulo, Estadão, Público, and El País.
Spanning three languages—English, Portuguese, and Spanish—these publications were chosen for their national prominence, broad digital reach, and continued influence in shaping public understanding of science. Notably, these outlets are often considered authoritative references in the digital age, frequently cited by major online knowledge repositories, such as Wikipedia.
Selling the Hunt For Alien Life
The study found that press releases often acted as key amplifiers for speculative content. In many cases, cautious statements made in scientific papers are exaggerated in press releases, which are then further dramatized in news stories.
For example, a study on the TRAPPIST-1 system cautiously noted among the planets in the star system, two were “most likely to be habitable.” That turned into a press release stating the planets “have been identified as most likely to be habitable,” and ultimately appeared in The Guardian as “Two planets in unusual star system are very likely habitable, scientists say.” In essence, what began as a measured scientific observation quickly escalated through the layers of science communication.
The researchers note that institutional press releases are frequently the first point at which exaggeration begins.
Because institutional publicity is often measured by the number of press releases that gain media traction, there is a strong incentive to amplify the perceived importance of a study.
Public relations departments, competing for attention and funding, may inflate the impact or implications of results to attract headlines. This dynamic places press information officers and science communicators under pressure to frame research in the most compelling and sometimes speculative light.
Consequently, press releases are often the initial source of speculative claims about the significance or promise of astrobiology studies, shaping the storyline long before it reaches journalists or the public.
Nevertheless, researchers also found that news articles were more likely to include speculative quotes from outside experts who were not directly involved in the research. These experts, often eager to contextualize findings, sometimes added their own hopeful spins or biases, further fueling expectations.
The most speculative claims were concentrated in stories about exoplanets, particularly those tied to the James Webb Space Telescope and the detection of potential biosignatures, such as dimethyl sulfide (DMS).
In September 2023, a paper published in The Astrophysical Journal Letters claimed the detection of faint hints of DMS in the atmosphere of K2-18b—a molecule associated with biological activity on Earth. Although the authors acknowledged the low statistical confidence (~1σ).
The following day, BBC News ran the headline “Tantalising sign of possible life on faraway world.” At the same time, journalist Pallab Ghosh tweeted it as “new tantalizing evidence of life.” The press attention was global—despite the weak signal and many unknowns.
The Weight of Expectation to find alien life
The study identifies three major categories of promises and expectations that commonly appear in public communications about the search for extraterrestrial life.
The first is detection, and the assertion or implication that the discovery of alien life is imminent or just around the corner. The second category is progress, which includes claims suggesting that science is rapidly advancing toward that goal, often portraying recent findings as key milestones.
The third is technology, encompassing statements that highlight how upcoming instruments, telescopes, or missions are expected to provide definitive answers in the near future. Together, these narratives help fuel public anticipation, often stretching beyond what the underlying data can confidently support.
While these themes were nearly absent from all scientific papers, they were common in press releases and especially news articles.
For example, a press release by the University of Cambridge about upcoming JWST observations paraphrased researchers as saying it “could mean that finding biosignatures of life outside our Solar System within the next few years is a real possibility.”
This matters, the researchers argue, because public perception drives funding decisions and political will.
“Science hype, the raising of expectations around the prospects of success of a field, can be a positive force by attracting the attention and inviting the contribution of the public and a plurality of societal actors to help shape the future direction of research,” the researchers write. “On the downside, failure of expectations can be damaging to the credibility of institutions associated with them.”
The Fine Line Between Hope and Hype
There’s nothing inherently wrong with speculation—especially in a field as inherently mysterious and boundary-pushing as astrobiology. However, the researchers caution that speculations should be clearly framed as such, not presented as conclusions.
“Speculative content, while not bound by strict demands of being accurate and truthful, influences societal factors involved in shaping the future of scientific and technological development,” the researchers note.
Efforts are underway to create more effective communication frameworks—such as the proposed Confidence of Life Detection (CoLD) scale, a numerical scale designed to guide the communication of research results. However, as researchers note, these ideas are not without controversy. Critics fear that rigid systems may stifle open discussion or be misused too easily.
Ultimately, the study urges journalists, press officers, and scientists to tread carefully when discussing the prospects of finding alien life.
“The current state of scientific knowledge about the prevalence of life in the universe is still highly uncertain,” researchers write. “We don’t know if life exists elsewhere in the universe, and we don’t know if we are ever going to reach a definite answer to the main question underlying the [Search for Life Elsewhere].”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com