Have we been visited by aliens? Harvard astronomer Loeb believes we have, basing his assertion on "evidence…collected over eleven days, starting on October 19, 2017," at a Hawaiian observatory. That's when the author, the director of the Black Hole Initiative and the Institute for Theory and Computation, and his fellow scientists unexpectedly observed the "first known interstellar visitor." It was a small object: "highly luminous, oddly tumbling, with a 91 percent probability of being disk-shaped." Moving roughly 58,900 miles per second, it "passed through our solar system and, without visible outgassing, smoothly accelerated from a path that deviated from the force of the sun's gravity alone." Loeb and his colleagues named it "Oumuamua," a Hawaiian word that roughly translates to scout. Though the scientific debate continues, writes the author, "the likelihood of scientists ever observing demonstrable proof is very remote." Loeb meticulously analyzes the evidence they have so far: No "confirmed interstellar object had ever been observed in our solar system," and it wasn't a comet or asteroid. Further research revealed that it rotated every eight hours and was approximately 100 yards long and less than 10 yards wide. Its unique, "smooth and steady" acceleration and deviation from the sun led the author to a hypothesis that charmed the media but generated "intense controversy and pushback" from other scientists. Loeb also delves into the object's spin rate, unchanging rotation, and the possibility that it might be another civilization's space hardware. After all, we've been "junking-up" space for years. Loeb issues a clarion call for a team of astro-archaeologists to increase research into possible alien life; unfortunately, the "conservative scientific community" has always fought against such research. It's hard to argue with the author's claim that it's the "height of arrogance to contend that we are unique," and he even speculates that life on Earth may be of Martian or interstellar origin. A tantalizing, probing inquiry into the possibilities of alien life. Copyright (c) Kirkus Reviews, used with permission.

On October 19, 2017, astronomers discovered 'Oumuamua, the first known interstellar object to pass through our solar system. But its behavior was strange. While many hypotheses have been presented to explain its anomalies, Loeb, the longest-serving chair of Harvard's Department of Astronomy and founder of the Black Hole Initiative, postulates the most likely explanation is that 'Oumuamua is evidence of extraterrestrial intelligence. He offers strong evidence to support this conclusion, but perhaps more valuable is how he uses this as a jumping-off point for much broader musings on the state of science. He critiques the tendency of science to be too conservative and the pernicious effects of scientific elitism toward the public. He considers the larger implications of what it would mean if we do obtain proof of other intelligent life in the universe, including the need for humanity to overcome our shortsightedness and invest in further exploration. Some of his digressions are a bit of a leap, but whether or not readers agree with him, his vision and curiosity are compelling.

Intelligent life is out there--or at least its cast-off equipment is­--and it's time earthlings dealt with it, argues Harvard physicist Loeb (The First Galaxies in the Universe) in this contentious manifesto. The author's concerns are twofold: first, he believes there is evidence for extraterrestrial life. Second, he posits that humans aren't prepared to accept that fact. This survey, then, is a brief on alien life and its implications for humanity. Loeb bases his case on 'Oumuamua, an interstellar object that baffled scientists when it appeared in 2017. Based on its shape, brightness, and trajectory, Loeb proposes it could be a reflective light sail made by extraterrestrial life. While his advice on how to find inhabited exoplanets is often ingenious ("one can distinguish an artificial source of light by the way it dims as it recedes from us"), less cogent is his attack on astronomical orthodoxy, which he considers too dismissive of research into extraterrestrial intelligence. He suggests that finding extraterrestrial life will help cure human arrogance and self-destructiveness: aliens, he contends, are likely to be "superior being" who can reveal "the meaning of life," though he also speculates they could turn out to be existentialists who believe that "life is absurd." Loeb's thought-provoking work of popular science will entertain those who wonder if humans are alone in the universe. Photos. (Jan.)