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A high-profile astronomer argues that the strange interstellar object ‘Oumuamua may be an alien signal

Extraterrestrial: The First Sign of Intelligent Life Beyond Earth

Avi Loeb
Houghton Mifflin Harcourt
240 pp.
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In the introduction of his sixth book, Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, Avi Loeb, chair of the Harvard Department of Astronomy, acknowledges the elephant in the room: “In the spirit of transparency, know that some scientists find my hypothesis unfashionable, outside of mainstream science, even dangerously ill conceived. But the most egregious error we can make, I believe, is not to take this possibility seriously enough.” The provocative possibility he refers to is that an interstellar object known as ‘Oumuamua (Hawaiian for “scout”), which passed through the Solar System in 2017, is an artificial object created by intelligent extraterrestrials.

Loeb, a prolific academic author, meticulously walks the reader through his reasoning, describing how, after accounting for ‘Oumuamua’s various anomalies—its orbit, size, shape, and density; its origin in velocity-position space; and its lack of an icy tail, among other properties—he calculates that its chance of arising naturally is less than one in a trillion. With the odds seemingly stacked against the scientific consensus that the object is a naturally occurring space rock, he wonders why so many researchers refuse to consider what he believes is an equally likely scenario, that the object is artificial, especially given the long-appreciated probability that life exists beyond Earth.

Loeb uses ‘Oumuamua to criticize what he perceives to be a long-standing trend in science toward falling in step with conventional positions rather than staking out contrarian concepts. While he holds science fiction and modern entertainment partially responsible for sensationalizing extraterrestrial life, he also claims that the astrophysics community has been derisive of and hostile toward research that engages with the possibility of extraterrestrial life.

The search for alien life is worth the cost, argues Loeb, especially given the resources dedicated to more-traditional fields that similarly lack tangible proof. “Despite the absence of experimental evidence,” he notes, “the mathematical ideas of supersymmetry, extra-spatial dimensions, string theory, Hawking radiation, and the multiverse are considered irrefutable and self-evident by the mainstream of theoretical physics.”

Loeb argues that we are not prepared to respond should alien life eventually contact us. He suggests that new disciplines should be developed to address this discrepancy, including the emerging field of space archaeology, which he believes would be well suited to search for techno- and biosignatures of extinct civilizations.

Regardless of the ultimate origins of ‘Oumuamua, our cognitive dissonance with regard to alien life must be acknowledged. We added gold-plated disks to the Voyager probes and plaques to the Pioneer probes to introduce ourselves to potentially intelligent extraterrestrials, we have provided government funding to organizations such as the SETI Institute, and we continue to spend billions of dollars looking for life beyond Earth, yet no official protocols have been established for how to send out signals or how to respond to extraterrestrial communication that we may encounter as a result of, or in spite of, those efforts. “Even a nascent treaty agreed to by all terrestrial signatories would provide a framework for how we, as a species, respond to an encounter with a mature intelligence,” Loeb argues.

Throughout the book, Loeb frames his nonconformist position on ‘Oumuamua as a teaching opportunity for students. He implores young scientists to seek out data-driven areas of investigation that go beyond popular paradigms, describing a number of instances in which leading scientists of the past failed to think beyond convention and by doing so, potentially delayed or even impeded fertile areas of research. He writes, for example, of Charles Townes, who in 1954 was discouraged by Nobel laureates Isidor Isaac Rabi and Polykarp Kusch from continuing his line of research on masers (the forerunner of lasers), who insisted that the technology would never work. Fortunately, he ignored them and persevered. Masers are an integral component of some global navigation satellite systems.

At the same time, Loeb entreats his peers to help foster research environments that encourage budding scientists to indulge their curiosity and seek out scientific truths. “If the flame of inquiry is to continue,” he writes, “it is incumbent on senior scholars to not only gather to themselves promising young scholars but to cultivate an environment within which the next generations of scientists can nurture discoveries despite their inherently unpredictable nature.”

About the author

The reviewer is at the Zvi Meitar Institute for Legal Implications of Emerging Technologies, Harry Radzyner Law School, Interdisciplinary Center, Herzliya, Israel, and the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.