Review: Reinventing SETIby Jeff Foust
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| His analysis is that there’s room for improvement for SETI. He is not afraid to take on central figures in the field and their legacies, like Drake and his eponymous equation. |
Those observations, along with others by terrestrial telescopes, have convinced nearly all astronomers and planetary scientists that 3I/ATLAS is an interstellar comet, ejected from some other solar system perhaps millions of years ago and now, by happenstance, is making a close pass by our solar system. All, that is, except for Harvard astronomer Avi Loeb, who thinks that, like two previous interstellar objects spotted passing through our solar system, 3I/ATLAS could be an artifact from an extraterrestrial civilization. In a recent essay, he estimated a 30–40% chance that 3I/ATLAS is artificial, even as evidence piles up that it is just a comet.
Loeb’s persistence in the face of data came to mind when reading the new book Reinventing SETI, although perhaps for reasons neither Loeb nor the book’s author, John Gertz, intended. Sixty-five years after Frank Drake conducted the first modern SETI effort, Project Ozma, Gertz argues in the book that the SETI field is in need of a reboot, turning away from traditional radiofrequency searches that have, so far, found no signs of civilizations beyond Earth.
Gertz comes to the topic as both an outsider and an insider. He is not a scientist, he acknowledges, but instead a businessman (his claim to fame, he notes in the book, is that he owns a company called ZORRO Productions that holds the rights to Zorro, the TV and movie character). However, he is also an amateur astronomer who became involved with the SETI Institute, joining its board and serving as its chairman, allowing him to see how SETI is practiced today.
His analysis is that there’s room for improvement for SETI. He is not afraid to take on central figures in the field and their legacies, like Drake and his eponymous equation (“I will presently brutalize the Drake Equation as a sacred cow ready for the ash heap of scientific history,” he writes in a chapter where he tears apart the terms of the equation and suggest it be revised to include exomoons and rogue planets that could host life, among other issues.) He offers an updated version but admits it can’t be used to compute the number of potential civilizations, a problem the original version had as well given a lack of knowledge about many of its variables.
He is critical of the long-running effort to use radio telescopes to listen for signals, something that has been going on since Project Ozma. Those radio searches make too many assumptions about how long alien civilizations might transmit and at what power level to make it worthwhile. (Oddly, despite that criticism he heaps praise on the privately funded Breakthrough Listen effort, which is simply using updated versions of radio observations.) Even if we were to detect something, he questions whether we could possibly decipher it.
Gertz also wonders whether any alien civilizations would make concerted efforts at transmissions, lest they draw attention to themselves by other, more predatory species. He adamantly opposes any efforts to transmit messages, known as Active SETI or Messaging to Extraterrestrial Intelligence (METI), devoting one chapter to an almost angry rebuttal of the concept: “I regard METI as dangerous, arrogant, delusional, unethical, unscientific, illegal, quasi-religious, cultic, and not merely foolish but downright stupid!” Got it.
He is in favor of alternative approaches, thinking that any extraterrestrial civilizations might eschew bits for atoms: probes sent to various solar systems to monitor any life there and be ready to communicate with it—or, maybe, extinguish it if it’s perceived as a threat. Those probes could be nodes in an interstellar network, he adds. “How do we know that every asteroid is in fact an asteroid and not one of these large transmitters? We don’t,” he writes.
| Efforts to transmit messages, he writes, are “dangerous, arrogant, delusional, unethical, unscientific, illegal, quasi-religious, cultic, and not merely foolish but downright stupid!” |
It sounds like something from a B-grade sci-fi movie, not in a book from an academic press. But he is serious about it and calls for more studies of solar system bodies to see which ones might be anomalous in some way. That brings to mind Loeb’s insistence that interstellar comets might be artificial, although Gertz curiously doesn’t mention that in his book. It’s worth noting that astronomers have taken spectra of thousands of asteroids, and only a few showed signs of being artificial, albeit terrestrial: near Earth objects that turned out to be spent rocket stages left in heliocentric orbits that occasionally come close to the Earth or Moon.
Loeb, in his essay, calls for efforts ranging from building a duplicate of the Vera C. Rubin Observatory in the northern hemisphere to spending half of current global military budgets—about $1 trillion annually—on developing interstellar spacecraft. (Good luck with that.) Gertz is more modest, seeking a bigger slice of the $70 billion he claims annually is spent on space science worldwide. (That is certainly a severe overestimate: NASA’s science directorate spent a little more than $7 billion in the just-concluded 2025 fiscal year, far more than any other space agency.) But then, most scientists think their fields are underfunded and could use a modest doubling or tripling of their budgets.
Gertz misses an obvious solution to his desire to support SETI: fund planetary science, specifically planetary defense. Rubin will soon dramatically increase the rate of asteroid discoveries, as well NASA’s NEO Surveyor infrared space telescope mission launching in a couple years. They will vastly expand the catalog of asteroids that can be searched for anomalous emissions or spectra. If nothing is found, those efforts will still have enriched our knowledge of the solar system. They may also detect near Earth objects whose potential impact may be far more serious a threat than alien berserker probes.
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