A new study examines how astrobiology and the Search for Life Elsewhere (SLE) are communicated in academic papers, press releases, and newspapers over nearly three decades. Using quantitative content analysis of 630 documents, the researchers show that speculations and expectations are more prevalent in press releases and news articles than in scientific papers. While speculation about life’s conditions and existence dominates media coverage, overt promises of imminent life detection remain rare. The findings highlight the tension between generating excitement and managing expectations, and call for more responsible communication to balance public engagement with scientific uncertainty.

 
Astrobiology—the study of life in the universe—sits at the crossroads of scientific discovery, public imagination, and cultural significance. Claims of possible extraterrestrial life have repeatedly captured global attention, from the Martian meteorite ALH84001 in 1996 to recent James Webb Space Telescope observations of exoplanets. But how are such claims communicated, and how do speculations and promises shape the public image of this developing field?

In a comprehensive new study published in PLOS One, Thilina Heenatigala (ELSI) along with collaborators, Danilo Albergaria, Pedro Russo, Ionica Smeets, and Dallyce Vetter from Leiden University analysed 630 documents spanning from 1996 to 2024: 188 scientific papers, 170 press releases, and 272 newspaper articles across English, Portuguese, and Spanish. Their goal was to understand how speculations and promises about the Search for Life Elsewhere (SLE) circulate between scientists, institutions, and the public.

The study found a consistent pattern: academic papers were the most cautious, with speculative content appearing far less frequently than in press releases and news coverage. In contrast, press releases and especially news articles often emphasised speculation about the conditions for life, the significance of discoveries, or even the possible existence of extraterrestrial organisms. For instance, while only 22.8% of papers speculated about conditions for life beyond Earth, such statements appeared in 47.6% of press releases and 56.6% of news articles.

Promises of progress or eventual detection of extraterrestrial life also showed this gradient. Scientific papers rarely contained explicit promises (0.5% for detection, 5.8% for progress), while press releases (22.9% for progress) and news articles (20.5% for progress) more frequently framed discoveries as steps forward. Technology-related expectations—such as the role of upcoming space telescopes—were particularly common in news coverage, with over one-third of news articles suggesting that new instruments would soon provide answers.

Importantly, the study shows that speculative framing is not merely journalistic exaggeration: it often originates in press releases, which are institutional communications written to promote research visibility. Quotes from scientists themselves were the most common source of speculative content in press releases, while journalists were more likely to include outside experts to contextualise or challenge claims. In some cases, cautious speculation in a scientific paper was amplified through press releases and ultimately transformed into strong, optimistic statements in headlines—illustrating how meaning can shift across communication stages.

The authors argue that this dynamic has both benefits and risks. On one hand, speculation and promises can engage the public, inspire curiosity, and support funding for ambitious missions. On the other, overpromising or overstating certainty risks damaging trust if expectations are not met. The team highlights that recent debates around proposed frameworks for communicating life detection (such as the “Confidence of Life Detection” scale) reflect this delicate balance.

Astrobiology is uniquely positioned at the boundary between science and society. As data from exoplanets and icy moons accumulate, claims of possible biosignatures are likely to enter the news cycle with increasing frequency. This study underscores the importance of responsible communication strategies that acknowledge uncertainty, clarify speculation, and provide realistic expectations for progress. In doing so, the field can continue to capture imaginations while maintaining credibility.