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Extraterrestrial: The First Sign of Intelligent Life Beyond Earth Kindle Edition

4.5 4.5 out of 5 stars 3,116 ratings

New York Times Bestseller | Wall Street Journal Bestseller | Publishers Weekly Bestseller | Publishers Marketplace 2020 Buzz Book  | Amazon Best Book of the Year | Longlisted for the 2022 PEN/E.O. Wilson Literary Science Writing Award


“Provocative and thrilling ... Loeb asks us to think big and to expect the unexpected.”

—Alan Lightman, New York Times bestselling author of Einstein’s Dreams and Searching for Stars on an Island in Maine


Harvard’s top astronomer lays out his controversial theory that our solar system was recently visited by advanced alien technology from a distant star.


In late 2017, scientists at a Hawaiian observatory glimpsed an object soaring through our inner solar system, moving so quickly that it could only have come from another star. Avi Loeb, Harvard’s top astronomer, showed it was not an asteroid; it was moving too fast along a strange orbit, and left no trail of gas or debris in its wake. There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization.


In Extraterrestrial, Loeb takes readers inside the thrilling story of the first interstellar visitor to be spotted in our solar system. He outlines his controversial theory and its profound implications: for science, for religion, and for the future of our species and our planet. A mind-bending journey through the furthest reaches of science, space-time, and the human imagination, Extraterrestrial challenges readers to aim for the stars—and to think critically about what’s out there, no matter how strange it seems.

Editorial Reviews

Review

"In this passionately argued, visionary book, astrophysicist Avi Loeb urges us to abandon the arrogant fantasy that we are the only sentient life form in the universe...The clues, as Loeb carefully reviews them, are fascinating."

-- "Stephen Greenblatt, Pulitzer Prize winner and New York Times bestselling author"

"Will provoke you to think about the possibility of intelligent life elsewhere in the universe in new and stimulating ways."

-- "Sean Carroll, New York Times bestselling author "

[A] thought-provoking work of popular science."

-- "Publishers Weekly"

"Provocative and thrilling...Loeb asks us to think big and to expect the unexpected."

-- "Alan Lightman, New York Times bestselling author"

"A tantalizing, probing inquiry."

-- "Kirkus Reviews"

"Fascinating and persuasive."

-- "New York Times Book Review"

"Part graceful memoir and part plea for keeping an open mind about the possibilities of what is out there in the universe...[from] one of the more imaginative and articulate scientists around."

-- "New York Times"

About the Author

ABRAHAM (AVI) LOEB is the Frank B. Baird, Jr., Professor of Science at Harvard University, chair of Harvard’s Department of Astronomy, founding director of Harvard’s Black Hole Initiative, and director of the Institute for Theory and Computation (ITC) within the Harvard-Smithsonian Center for Astrophysics. He also chairs the Advisory Committee for the Breakthrough Starshot Initiative, and serves as the science theory director for all Initiatives of the Breakthrough Prize Foundation, as well as chair of the Board on Physics and Astronomy of the National Academies. Author of four books and over 700 scientific papers, Loeb is an elected fellow of the American Academy of Arts & Sciences, the American Physical Society, and the International Academy of Astronautics. In 2012, Time selected Loeb as one of the twenty-five most influential people in space.

Product details

  • ASIN ‏ : ‎ B081TTY4NX
  • Publisher ‏ : ‎ Mariner Books (January 26, 2021)
  • Publication date ‏ : ‎ January 26, 2021
  • Language ‏ : ‎ English
  • File size ‏ : ‎ 8876 KB
  • Text-to-Speech ‏ : ‎ Enabled
  • Screen Reader ‏ : ‎ Supported
  • Enhanced typesetting ‏ : ‎ Enabled
  • X-Ray ‏ : ‎ Enabled
  • Word Wise ‏ : ‎ Enabled
  • Sticky notes ‏ : ‎ On Kindle Scribe
  • Print length ‏ : ‎ 245 pages
  • Customer Reviews:
    4.5 4.5 out of 5 stars 3,116 ratings

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Customer reviews

4.5 out of 5 stars
4.5 out of 5
3,116 global ratings
A Potential Alien Technosignature & Good Critique of Space Scientists
4 Stars
A Potential Alien Technosignature & Good Critique of Space Scientists
This is a good book as long as you can tolerate the rather slow initial chapters of filler which I assume were needed to make it long enough for the publisher's requirements. I have seen that some other comments highlight this slow start and it put off readers. Perhaps some will want to skip ahead to the chapters on Oumuamua.I really appreciated the detailed evaluation of the Oumuamua data and was surprised to hear that the object was likely an extremely thin circular artefact. All of the major media has shown us the rocky cigar-shaped body which was first suspected based on the astronomical information returned to earth. I have added an image that shows such a possible solar sail design that would mesh well with the Oumuamua described by Loeb in the book. Because we can't yet send a super fast probe to directly sample this visitor or build a telescope that would see it in detail, there is no way to be absolute on artificiality, but Loeb makes a strong case based on what we do know. Even the intellectual opponents have to come up with exotic solutions to the anomalies involved, no asteroid or comet that we know would fulfil the role.A good part of the book is reserved for criticism of academia, the conservatism and bias that relegates the search for alien intelligence to a joke subject, one that young scientists should avoid if they want to establish a respected name for themselves. This is ironic when considering the public have enormous interest in the possibility such aliens exist and may visit us (past, present or future). Loeb is attempting to change this situation and open a door through which a new generation of space scientists may walk."If you're not ready to find exceptional things, you won't discover them. Of course, every argument needs to be based on evidence, but if the evidence points to an anomaly, we need to talk about an anomaly." - Avi LoebPersonally, I believe Oumuamua 'may' by a true alien technosignature, but in my opinion the case is not as strong as the indications surrounding the object which arrived here 780,000 years ago, parking itself in orbit before leaving behind mysterious highly silica debris. If anyone wants to learn more on that I have provided a good many interviews and discussed the matter in my own book. Hopefully, I can write an acceptable paper on the topic but being from beyond the hallowed halls of academia that is beyond my wheelhouse.I think Extraterrestrial: The First Sign of Intelligent Life Beyond Earth will change the conversation on alien life and make more conservative people open their minds, but for some the subject will always be a joke and nothing the professor says will change that. Well worth reading!Disclosure: I read a free review copy as science editor for the Earth Ancients podcast.
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Top reviews from the United States

Reviewed in the United States on January 31, 2021
The book entitled: “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” by Avi Loeb was fascinating and compelling on several fronts.
Professor Loeb begins with writing: “When you get a chance, step outside and admire the universe. This is best done at night, of course. … Just looking up, I find, helps change your perspective.” Moreover, he states: “This book confronts one of these profound questions, arguably the most consequential: Are we alone?” The author reminds us: “The world will end, of course, and most decidedly with a bang; our Sun, now about 4.6 billion years old, will in about 7 billion years turn into an expanding red giant and end all life on Earth. This is not up for debate, nor is it an ethical matter.”
As Professor Loeb states: “I remind my students that, as Galileo Galilei argued after looking through his telescope, evidence doesn’t care about approval.” The author goes on to set the stage “Contemplating the sky and the universe beyond teaches us humility. Cosmic space and time have vast scales. There are more than a billion trillion sun-like stars in the observable volume of the universe, and even the luckiest among us live for merely 1 percent of a millionth of the lifetime of the Sun . … Most of the evidence this book wrestles with was collected over eleven days, starting on October 19, 2017. That was the length of time we had to observe the first known interstellar visitor.”
The author encourages the reader to open their minds to the possibility of life beyond earth and goes on to explain why including explicit observations that support that hypothesis. His writing style is entertaining introducing you to his background and who he is and how he got to be a professor at Harvard. While the main theme of the book is about the discovery … “On October 19, astronomer Robert Weryk at the Haleakala Observatory discovered ‘Oumuamua in the data collected by the Pan-STARRS telescope, images that showed the object as a point of light speeding across the sky, moving too quickly to be bound by the Sun’s gravity. … The Hawaiian word ‘oumuamua (pronounced “oh moo ah moo ah”) is loosely translated as “scout.” Professor Loeb goes on to explain: “‘Oumuamua’s trajectory, its speed, and its approximate size (it was under one-quarter of a mile in diameter). None of these early details suggested that ‘Oumuamua was unusual for any reason other than its origin outside our star system.” Moreover, as he builds his case that this could be an extraterrestrial for the reader he goes on to state: “In the case of ‘Oumuamua, the object’s brightness varied tenfold every eight hours, which we deduced to be the amount of time that it took to complete one full rotation. This dramatic variability in its brightness told us that ‘Oumuamua’s shape was extreme, or at least five to ten times longer than it was wide. In a manner that he is comfortable with, Loeb states: “As with any good detective story, the evidence that emerged about ‘Oumuamua in the year after its discovery allowed us to abandon certain theories and winnow out hypotheses that did not fit the facts.”
Some of the other topics that Loeb explores include: “The Milky Way hosts tens of billions of Earth-size planets with surface temperatures similar to our own. Overall, about a quarter of our galaxy’s two hundred billion stars are orbited by planets that are habitable in the way Earth is, with surface conditions that allow liquid water and the chemistry of life as we know it.” And goes on to state “that’s counting only habitable planets within the Milky Way. Adding all other galaxies in the observable volume of the universe increases the number of habitable planets to a zetta, [or 10 to the 21st power] —a figure greater than the number of grains of sand on all of the beaches on Earth. In response to: “A billionaire entrepreneur from Silicon Valley, Yuri Milner … wanted to support a team that would engineer and launch spacecraft capable of reaching the star system closest to ours: Alpha Centauri, a group of three stars orbiting one another some 4.27 light-years from Earth.” Loeb et al. spent 6 months developing a probe that would be launched and return in less than a human’s life time. As Loeb reports: “The vision of visiting another star within our lifetimes captivated the public’s imagination in a way reminiscent of the Apollo 11 moon landing.”
Bouncing back to an earlier main topic, Professor Loeb posits: “‘Oumuamua must have been designed, built, and launched by an extraterrestrial intelligence.”
Dealing with the press: the author recalls: “the reporter asked, “Do you believe there are alien civilizations out there?” “A quarter of all stars host a planet the size and surface temperature of the Earth,” I said into the camera. “It would be arrogant to think we are alone.”” And again to the main topic of the book: “Matthew Knight, declared, “We have never seen anything like ‘Oumuamua in our solar system. It’s really a mystery still,” and then added, “but our preference is to stick with analogues we know.” … The interviewer for the German newspaper Der Spiegel put it with admirable bluntness: “According to a proverb, whoever has only a hammer will see nothing but nails.””
Going back, Loeb states: “Perhaps long, long ago, ‘Oumuamua was not junk but extraterrestrial technological equipment built for a distinct purpose. Perhaps it was something closer in intent to a buoy.” Professor Loeb values an open mind stating: “For me, it echoes a much older thought, one attributed to Heraclitus of Ephesus: “If you do not expect the unexpected, you will not find it.””
This reviewer has long been aware of natural tensions between those who mostly belief in theory and those who mostly belief in data; indeed some great theoretical physics work occurred because opportunities to work with data were restricted. Clearly, Professor Loeb is more data oriented stating: “Too often astrophysics can lose itself in theories that float free of any evidence, taking funding and talent with them.” As additional insight into the techniques that the professor employs, this reviewer is more familiar with the concept of writing an hypothesis and collecting data to either refute or support the hypothesis, for the ‘Oumuamua situation, the data is the data and the investigators are driven to look at it from all different aspects but not allowed the benefit of collecting more data; this is quite a challenge and may explain the reluctance of many scientists to move outside of their comfort zone
Professor Loeb is an excellent spokesperson for funding of science but he is not shy of objecting to the restrictions placed on science investigations by review committees and questions some investments made, stating, for example, “Just a bit under five billion dollars was spent to construct the Large Hadron Collider, a particle accelerator built in hopes of attaining confirming evidence of supersymmetry, and running it costs another one billion dollars a year. … when they insist that the multiverse must exist despite there being no data to support the theory, they are wasting precious time and money and talent. And we have not only finite funds to spend, but finite time.”
The author states: “Science is a work in progress, and the pursuit of scientific knowledge is never-ending. But that progress does not follow a straight path, and the obstacles encountered are sometimes of humanity’s own making. … in August 1909, Edward Charles Pickering argued in a Popular Science Monthly article that telescopes had reached their optimal size, fifty to seventy inches, and there was thus little point in building instruments with larger apertures. … Pickering was mistaken, of course; telescopes with larger apertures collect more photons, allowing scientists to see farther out into the cosmos and deeper into the past. … Pickering had erred due to his arrogance. … Unfortunately, Pickering was not unique in this particular blunder. Indeed, it is a recurrent mistake throughout the history of science.”
Loeb writes: “We date the birth of the universe, the Big Bang, to some 13.8 billion years ago. Fascinating, revelatory work has been done that has produced theory, data, and confirmed predictions concerning the universe’s earliest origins, including the common agreement that after the first hundred million years, everything was cloaked in darkness. Until, that is, the first star was born. … Because light travels at a finite speed, the farther out we look, the farther back in time we see.”
In terms of finding other life, the author writes: “Fermi raised a simple, provocative question: How do we explain the paradox that, given the vastness of the universe, the probability of extraterrestrial life seems high, yet there is no certain evidence for anything but terrestrial life? If life is common in the universe, he asked, “Where is everybody?” … Over the years, many answers have been formulated.
In 1998, the economist Robin Hanson published an essay titled “The Great Filter—Are We Almost Past It?” … Hanson argued, that throughout the universe a civilization’s own technological advancement overwhelmingly predicts its destruction. The very moment when a civilization reaches our stage of technological advancement—is also the moment when its technological maturity becomes sufficient for its own destruction…
Professor Loeb argues for a new discipline Astro-Archaeology stating: “We are greatly in need of a new branch of astronomy, what I have termed space archaeology. Similar to archaeologists who dig into the ground to learn about, say, Mayan society, astronomers must start searching for technological civilizations by digging into space.” Writing of life on other planets, Loeb goes on: “Over the past two decades, we have learned that the universe contains numerous exoplanets (the technical term for any planet residing outside the solar system). This spate of discoveries began in 1995, when astronomers Michel Mayor and Didier Queloz became the first to find definitive observational evidence for an exoplanet— … Their pioneering work ushered in the new era of hunting exoplanets and earned them a Nobel Prize in 2019.”
Loeb brings up some potentially controversial topics including the concept of sending biological seeds from our planet: “Selective and spontaneous adaptations that increase life’s ability to persevere is the bedrock of Darwinian biology. Life’s aim is survival, which means propagation. Those seeds need not even be restricted to bacteria. Certain viruses, which are also capable of Darwinian evolution, have proven themselves sufficiently durable. … How to ensure life is safely ejected from a planet? Eject it yourself.” He is also optimistic or perhaps naïve to expect superior beings to be benevolent.
In terms of truth in science, Loeb reminds the reader: “Galileo is supposed to have declared after looking through his telescope, “In the sciences, the authority of a thousand is not worth as much as the humble reasoning of a single individual.” Einstein, centuries later, got at the same idea when twenty-eight scholars contributed essays to a 1931 book titled A Hundred Authors Against Einstein that declared his theory of general relativity wrong. … is supposed to have replied that if he were wrong, then one author with conclusive evidence to disprove the theory would have been sufficient.”
One of the refreshing techniques in the book is that the author He is one of the few published professors I have seen who goes out of his way to explicitly credit by name several of his students and post-docs.
Bottom line about this book: it is interesting and informative and includes evidence for extraterrestrial life and how scientific methods advance our understanding of the universe; the book is worth purchasing and reading especially for those scientifically inclined.
30 people found this helpful
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Reviewed in the United States on March 20, 2024
Great read and Avi is ahead of his time in regards to exploring the universe and offers beneficial ideas as to discovering life in our universe.
Reviewed in the United States on March 2, 2021
I found this an interesting take on a somewhat taboo scientific subject. I think Avi Loeb makes a compelling argument why the Oumaumua interstellar object may have indeed been more than just an unusual comet or rock, and could possibly be of artificial origin. Unfortunately, we'll likely never know. The more important argument Loeb makes is the negative bias that science in general places on the study of extraterrestrial intelligence that may indeed hinder us from confirming an observation when presented in plain sight.

I gave this book four out of five stars. Although I understand that the author was trying to explain how his personal upbringing, experience and training enabled him to draw some of his conclusions, I thought that at times, he comes off just a bit too self congratulatory. On the other hand, he does an outstanding job explaining very technical ideas in a way us lay people can more easily understand. I would imagine his students love him... I'd go to a lecture of his in a hot second.
2 people found this helpful
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Reviewed in the United States on January 25, 2024
This was a very informative book that delved into many aspects of the discovery process for astronomical observations and how they are applied in practice. I also found the biography portions of Mr. Loeb’s life fascinating.

The author, Avi Loeb, makes cogent points about the current state of the astronomical community and how it handles the discoveries as they’re happening. The rigorous application of the scientific process gives his arguments more weight, making those of the IAU seem weak by comparison.

I enjoyed reading this book and highly recommend it to anyone who is interested in learning more about this subject.
Reviewed in the United States on April 9, 2024
This is the book that would provide someone new ideas to understand our universe. Classic theories were new concepts before being accepted by the scientific field. It is better to consider all the possibilities no matter how some ideas or proposals are against the established concepts. The author described some novice concepts that would open one's mind.
Reviewed in the United States on January 25, 2024
I'm afraid I purchased the wrong book. I think I wanted the first book on the subject which came recommended. Interesting point of view on what the object that came flying past Earth really was or could be. This came across to me as squeezing out a second title based on the original event. This deals too much with the behind the scenes private life and thoughts of the author. Less interesting. Not enough science.

Top reviews from other countries

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Graciano Bello
5.0 out of 5 stars Apertura de mente
Reviewed in Mexico on February 22, 2022
Excelente libro. Ademas de los aspectos científicos relacionados con el hallazgo de Oumuamua, lo importante es tener una mente abierta, buscar otras opciones, otras posibilidades, no conformarse con lo establecido. No ser miopes en nuestra vida.
Ignacio Monclús
5.0 out of 5 stars Maravilloso
Reviewed in Spain on December 27, 2023
Muchas cosas para ver y mucho más por conocer. El libro lanza hipótesis plausibles, pero algo debería ser probado pronto.
Marcos
5.0 out of 5 stars Abordagem puramente científica do assunto
Reviewed in Brazil on March 24, 2021
O livro é muito interessante, não apenas por focar na possibilidade do objeto ser um artefato alienígena, mas pela abordagem científica e por revelar a hipocrisia que pode existir nos bastidores dos investimentos realizados em nome da causa da ciência, e do atraso que isto acarreta na nossa evolução como civilização.
One person found this helpful
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wonndatt
5.0 out of 5 stars Brilliant! Readable! Inspirational!
Reviewed in Canada on February 1, 2021
As a non-Scientist, with a huge curiosity about what space exploration, I found this book an easy, educational, and enjoyable read. We will be hearing much more from Avi Loeb and his unique gifts.
5 people found this helpful
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Dr. Hugh Deasy
5.0 out of 5 stars Truly scientific method allied fearlessly
Reviewed in Germany on June 25, 2022
Not only does Avi reveal more details of the unusual not to mention unique aspects of Oumuamua than any other researcher, but he also discusses at length what is wrong with the current academic attitudes to truly challenging phenomena. First using the example of Oumuamua, he shows that there are 6 or more unique aspects to the case, and not just 2 or 3 as most researchers maintain. The latter seem to be seeking to play down the truly challenging aspects of the case. This is because to admit all the challenging aspects would be to show that the evidence points clearly, using Occam's razor, to a 91% probability of an extraterrestrial technological nature of the object. And the ET hypothesis is shown to need less extreme concatenations of events than proposals for a natural origin: the latter include hydrogen ice just enough scraped off a hydrogen ice planetoid. The number of such unusual objects that would have to be produced makes it extremely unlikely that we would have observed one of these in the lifetime of the galaxy. It is calculations of this sort that are the stuff of good research and this is what this book exudes in every page. So if you are of a scientific leaning then this book will make a very good case for Oumuamua having been a defunct light sail and possibly a beacon set to be at the mean velocity of the local stellar environment. In this case it was the solar system that bumped into this beacon, and not vice versa.
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