Did NASA Miss Viking’s Discovery of Life on Mars?
Mainstream scientists warn us about false positives, namely misleading claims for interesting signals that are not substantiated by sufficient evidence. Indeed, the job of science is not done when a signal is detected. The discoverers must demonstrate that the signal is statistically significant relative to the noise and cannot entertain mundane interpretations.
At the same time, discoveries often emerge out of a fog of uncertainty. They are flagged by anomalies that the risk-averse scientific community initially ignores because of the mental comfort of following the herd.
Innovative scientists warn us about false negatives, namely the dismissal of preliminary intriguing evidence that ushers in an important discovery. The incentive for mainstream debunkers is to minimize mistakes, but their attitude carries the collateral damage of throwing precious babies (signals) along with the unwanted bathwater (noise).
Scientific criticism is helpful as long as it recognizes that disruptive ideas are as vulnerable as newly born babies. We must handle infants with gentle care and respect rather than with aggressive moves that are commonly exchanged among adults. An acidic academic culture does not only kill bad microorganisms in the gut of science. It also kills well-intended engines of discovery at the same time.
I personally experienced this acidic culture when I first proposed in 2018 that the flat shape and non-gravitational acceleration of the interstellar object 1I\`Oumuamua should be considered as potential techno-signatures (as discussed here). In response, mainstream comet experts dismissed this notion and redefined the object as a `dark comet’ (as discussed here) — namely a comet that does not show visible signs of outgassing. They behaved like the adults in Hans Christian Andersen’s tale who told the kid that the emperor wears invisible clothes. By attempting to avoid a false positive out of prejudice, they might have created a false negative. This became clear when a similarly defined `dark comet’, labeled 1998 KY26, was shown in a recent paper that I co-authored here, to be the shiny, rapidly spinning counterpart to the failed soviet spacecraft Phobos 1.
The acidic culture which resists potential techno-signatures is also active in its resistance to potential biosignatures.
A new Perspective article in Nature Astronomy, accessible here, discusses the pitfalls of avoiding false negatives in the search for extraterrestrial life within the mainstream of astrobiology. The failure to recognize microbial life when the evidence suggests it, was demonstrated during the missions of the Viking 1 and 2 spacecraft, which landed on Mars on July 20 and September 3, 1976, respectively. The spacecraft scooped up samples of Martian soil and treated them with nutrients, water, and heat, and searched for signs of biology, such as the release of radioactively tagged carbon gasses, or the absorption of carbon monoxide and carbon dioxide in the soil. In particular, the Labelled Release experiment — designed to detect active metabolism, measured 14CO2 emission during exposure of regolith samples to growth medium, a result consistent with biological growth. These Labelled Release results were, however, framed as merely anomalous, when it was concluded that the Martian regolith was free of organic matter and therefore lifeless. In other words, mainstream scientists dismissed the findings while claiming that abiotic processes could account for the data.
The Viking landers from 50 years ago were the first and only missions so far explicitly designed to search for biological activity on Mars. Why did NASA never attempt to reproduce their results over the past 50 years? The only plausible explanation is that the risk-averse astrobiology community restrained itself from finding life in the same way, because of the controversy generated by the Viking results. This is exactly the opposite mindset of a curious and open-minded research community.
The brilliant Dr. Steven Benner just wrote a 400-page book on this topic (to be published by Penguin Press on July 23, 2026 — the 50th anniversary of Viking’s studies. His first paper to question the interpretation of the Viking results was published in 2000 here and his latest paper on the subject was just published in 2026 here.
The biggest challenge to human cognition is separating a perception of reality based on a limited training data set from reality itself. The U.S. is investing 700 billion dollars this year in data centers for training AI systems, because it is widely recognized that the quality of the AI assessments reflects the size of their training data. This insight obviously applies for human intelligence as well. The only way for astrobiologists to figure out whether the Viking results imply the existence of living organisms in the Martian soil is to repeat Viking’s Labelled Release experiment in search for active metabolism. The mistake of the astrobiology community is not only in resisting Viking’s metabolism signal but mainly in never checking over the past 50 years whether it was real!
There is clear evidence that disruptive science is in decline (as quantified here). A simple remedy is to approach innovative findings with the gentle care applied to unborn babies. Rather than ridiculing the deliverers, we should celebrate the excitement lurking in the potential truth within their findings. The wise choice is to embark on the collection of new data that will vet their findings. Without a dose of curiosity and humility to learn, we will never seek the evidence necessary for disruptive discoveries.
Unfortunately, the graveyard of science is filled with unborn babies.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, former director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. The paperback edition of his new book, titled “Interstellar”, was published in August 2024.
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