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A Brief Guide to Aliens: are we alone in the universe?
Astrophysicist Adam Frank guides us through the search for extraterrestrial life and the questions we stand ready to answer.
‘With wit and brio, Frank separates current nonsense about aliens from the serious and fascinating search for extraterrestrial life’ Carlo Rovelli, New York Times bestselling author of Seven Brief Lessons on Physics
‘Adam Frank has written a page-turner on the search for intelligent life in the universe’ Scott Derrickson, director of Marvel Studio’s Doctor Strange
Everyone is curious about life in the Universe, UFOs and whether ET is out there. Over the course of his thirty-year career as an astrophysicist, Adam Frank has consistently been asked about the possibility of intelligent life in the universe. Are aliens real? Where are they? Why haven’t we found them? What happens if we do?
We’ve long been led to believe that astronomers spend every night searching the sky for extraterrestials, but the truth is we have barely started looking. Not until now have we even known where to look or how. In A Brief Guide to Aliens, Frank, a leading researcher in the field, takes us on a journey to all that we know about the possibility of life outside planet Earth and shows us the cutting-edge science that has brought us to this unique moment in human the one where we go find out for ourselves.
In this brief guide with big stakes, Frank gives us a rundown of everything we need to know, from the scientific origins of the search for intelligent life, the Fermi Paradox, the Kardashev Scale, the James Webb Telescope, as well as UFOs and their conspiracy theories. Drawing from his own work and that of other scientists studying the possibility of alien life, he brings together the latest scientific thinking, data, ideas, and discoveries to equip us with the critical facts as we stand at what may be the last moment in human history where we still believe we are all alone. This book is about everything we do—and do not—know about life, intelligent or otherwise beyond Earth. In language that is engaging, entertaining and fun, A Brief Guide to Aliens provides a comprehensive first look at how close we are to finding out if others actually exist—and if they do, what they might be like.
Humankind is on the precipice of finding its neighbours. So, what comes next? No person is better suited to answer that question – and lead the search – than Adam Frank.
‘This wonderful book unravels the tangled ball of humanity’s thinking about aliens, and tells the whole story with high humor and immense clarity’ Kim Stanley Robinson, author of The Ministry for the Future and the Mars trilogy
‘Frank’s book is science writing at its best, revealing the awe-inspiring capacity of science to help us understand, and navigate, the universe’ Annaka Harris
‘Aliens and UFOs have held perennial fascination for us all. Now, Adam Frank gives us an entertaining romp through our quickly changing attitudes to these topics’ Martin Rees
‘If aliens do land on Earth one day, I hope they choose Adam Frank’s backyard. They will be up for an awesome first encounter with a first-rate scientist and human being’ Marcelo Gleiser
‘With a chatty mix of wit and wisdom, Adam Frank comprehensively covers a wide range of topics from historical details to claims of modern-day sightings, while shedding light on our enduring fascination with the concept of aliens’<
‘With wit and brio, Frank separates current nonsense about aliens from the serious and fascinating search for extraterrestrial life’ Carlo Rovelli, New York Times bestselling author of Seven Brief Lessons on Physics
‘Adam Frank has written a page-turner on the search for intelligent life in the universe’ Scott Derrickson, director of Marvel Studio’s Doctor Strange
Everyone is curious about life in the Universe, UFOs and whether ET is out there. Over the course of his thirty-year career as an astrophysicist, Adam Frank has consistently been asked about the possibility of intelligent life in the universe. Are aliens real? Where are they? Why haven’t we found them? What happens if we do?
We’ve long been led to believe that astronomers spend every night searching the sky for extraterrestials, but the truth is we have barely started looking. Not until now have we even known where to look or how. In A Brief Guide to Aliens, Frank, a leading researcher in the field, takes us on a journey to all that we know about the possibility of life outside planet Earth and shows us the cutting-edge science that has brought us to this unique moment in human the one where we go find out for ourselves.
In this brief guide with big stakes, Frank gives us a rundown of everything we need to know, from the scientific origins of the search for intelligent life, the Fermi Paradox, the Kardashev Scale, the James Webb Telescope, as well as UFOs and their conspiracy theories. Drawing from his own work and that of other scientists studying the possibility of alien life, he brings together the latest scientific thinking, data, ideas, and discoveries to equip us with the critical facts as we stand at what may be the last moment in human history where we still believe we are all alone. This book is about everything we do—and do not—know about life, intelligent or otherwise beyond Earth. In language that is engaging, entertaining and fun, A Brief Guide to Aliens provides a comprehensive first look at how close we are to finding out if others actually exist—and if they do, what they might be like.
Humankind is on the precipice of finding its neighbours. So, what comes next? No person is better suited to answer that question – and lead the search – than Adam Frank.
‘This wonderful book unravels the tangled ball of humanity’s thinking about aliens, and tells the whole story with high humor and immense clarity’ Kim Stanley Robinson, author of The Ministry for the Future and the Mars trilogy
‘Frank’s book is science writing at its best, revealing the awe-inspiring capacity of science to help us understand, and navigate, the universe’ Annaka Harris
‘Aliens and UFOs have held perennial fascination for us all. Now, Adam Frank gives us an entertaining romp through our quickly changing attitudes to these topics’ Martin Rees
‘If aliens do land on Earth one day, I hope they choose Adam Frank’s backyard. They will be up for an awesome first encounter with a first-rate scientist and human being’ Marcelo Gleiser
‘With a chatty mix of wit and wisdom, Adam Frank comprehensively covers a wide range of topics from historical details to claims of modern-day sightings, while shedding light on our enduring fascination with the concept of aliens’<
255 pages, Kindle Edition
Published June 26, 2024
3 people are currently reading
20 people want to read
About the author
Adam Frank
25 books174 followersAdam Frank is a professor of astrophysics at the University of Rochester. He is a co-founder of NPR’s 13.7: Cosmos and Culture blog and an on-air commentator for All Things Considered. He also served as the science consultant for Marvel Studio’s Dr. Strange. He lives in Rochester, New York.
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Displaying 1 - 2 of 2 reviews
November 23, 2025
Adam Frank's A Brief Guide to Aliens asks humanity's oldest question using modern science. We live in an era where thousands of exoplanets are confirmed, SETI is legitimate research, and governments finally take the question seriously. Yet conversation around alien life remains muddled by UFO conspiracies and Hollywood fantasies. Frank untangles this, showing what astrobiology can actually tell us about whether we're alone.
Frank begins with personal vulnerability: childhood obsession with aliens sparked by his father's pulp science fiction magazines. This establishes his credibility as someone bridging the scientist and the human who understands why this question captivates us.
Two Millennia of Arguing About Nothing
Frank traces humanity's longest argument back to ancient Greece. Aristotle argued alien life was impossible, claiming Earth uniquely inhabited. For 1,900 years, the Western world accepted his word. Yet Epicurus and the atomists disagreed, reasoning infinite worlds must exist with infinite life.
The debate's fundamental structure hasn't changed in 2,500 years - only the terms. We still have "alien optimists" and "alien pessimists." Throughout history, brilliant people argued both positions with nothing but opinions.
Then came Giordano Bruno. This radical Dominican monk accepted heliocentrism, logically concluding stars were other suns with inhabited planets. The Catholic Church wasn't amused. Bruno was burned alive at the stake. Frank notes with dark humor: "The alien debate has definitely gotten heated in the past."
In 1950, physicist Enrico Fermi asked colleagues discussing interstellar travel: "But where is everybody?" If advanced civilizations are common, they should already be everywhere. The Milky Way spans 100,000 light-years; at even fractional light-speed, civilizations could colonize it in hundreds of thousands of years - a cosmic blink compared to 13.6 billion years.
Michael H. Hart suggested absence of aliens proves we're alone - the "Great Filter" hypothesis. Others proposed the "zoo hypothesis": aliens exist but deliberately avoid us. Carl Sagan suggested spacefaring civilizations stall due to resource constraints. Frank's crucial correction: Fermi's Paradox only addresses why aliens aren't here now - it says nothing about distant signals. Humanity has searched about one hot-tub's worth of water from the entire ocean of space.
In 1961, Frank Drake created an equation revolutionizing how scientists think about alien life. The Drake Equation breaks "How many advanced civilizations exist?" into components: star formation rate, fraction with planets, habitable planets per system, probability life forms, intelligence evolves, civilizations arise, and their lifespan.
Frank emphasizes this is a clarity tool, not prediction. When formulated in 1961, only one term was known. Now we know essentially all stars have planets and about one-in-five has habitable-zone planets. In optimistic scenarios (all probabilities favorable, civilizations last billions of years), you get 200 million civilizations. In pessimistic versions, you get zero. The equation lets us see exactly where optimists and pessimists disagree.
On June 24, 1947, pilot Kenneth Arnold saw nine strange objects near Mount Rainier, traveling over 1,500 mph. He described them as moving "like a saucer skipped across water." Newspapers misquoted him as "flying saucer" - UFO culture was born in a journalistic error. Once the phrase existed, 830 flying saucer reports flooded in. People started seeing what newspapers told them to see.
Then came Roswell. Rancher W.W. Brazel found debris (rubber, tinfoil, sticks). Major Jesse Marcel announced they'd found a "flying saucer." The War Department quickly countered it was a weather balloon. The story died for thirty years.
Around 1980, researcher Stanton Friedman revived it. New claims emerged: alien bodies recovered, government cover-up. Each book added sensational details. In 1997, the government admitted covering up Roswell - but it was Project Mogul, secret balloons monitoring Soviet nuclear tests, not aliens.
he UFO circus created a "giggle factor" around serious SETI research. Scientists proposing to search for extraterrestrial intelligence faced dismissal, tarred by association with UFO true-believers and government obfuscation.
The CIA's 1953 Robertson Panel secretly concluded UFO reports- real or not- could destabilize public order. They recommended the government publicly debunk all reports for "stability." Translation: keep people ignorant for political control.
Project Blue Book investigated over 12,000 cases, finding about 11,300 explainable. Only ~6% resisted explanation—though "resisted" often meant insufficient data, not proof of aliens. Physicist Edward Condon's independent investigation (1966) concluded UFOs held nothing to interest science. The American Association for the Advancement of Science endorsed this.
Frank pivots to astrobiology. The habitable zone - where temperatures allow liquid water - is key. Not all exoplanets are equal; Drake's habitable zone defines regions where life might emerge.
Recent evidence suggests ocean moons like Europa have subsurface oceans deeper than Earth's and potential hydrothermal vents. Exoplanet discoveries show tens of thousands confirmed; one estimate suggests ten billion trillion habitable planets exist.
On alien life itself, Frank shows why carbon is special: it forms stable bonds enabling complex chemistry. Life repeatedly "invented" similar solutions - eyes, wings, locomotion evolved independently multiple times. So might aliens have sensory organs? Possibly. But details depend on planetary gravity, atmosphere, light wavelengths.
Frank's greatest strength is explaining complex concepts clearly without dumbing them down. The Drake Equation becomes intuitive. The Fermi Paradox transforms into a thinking framework. The UFO circus gains historical context.
Sections on alien consciousness, ethics, and what civilizations look like veer toward informed speculation rather than hard science. Frank labels these explorations, not predictions, but some readers may want more definitive answers. The UFO treatment, while balanced, reads diplomatically- scientifically, precious little evidence supports the extraterrestrial hypothesis. As a "brief guide," complex topics feel compressed; deeper dives require supplementary sources.
Frank's A Brief Guide to Aliens is what popular science should be: intellectually rigorous, accessible, historically informed, engaging both wonder and skepticism. He shows asking "Are we alone?" is scientifically rigorous, finally answerable with telescopes and data, not opinion. That's genuinely exciting.
Who should read this:
Anyone curious about alien life, astrobiology, exoplanets, SETI.
Those wanting contemporary science perspectives.
Readers frustrated by UFO conspiracy culture.
Scientists in astrobiology.
Students.
Anyone who loved Carl Sagan.
Frank begins with personal vulnerability: childhood obsession with aliens sparked by his father's pulp science fiction magazines. This establishes his credibility as someone bridging the scientist and the human who understands why this question captivates us.
Two Millennia of Arguing About Nothing
Frank traces humanity's longest argument back to ancient Greece. Aristotle argued alien life was impossible, claiming Earth uniquely inhabited. For 1,900 years, the Western world accepted his word. Yet Epicurus and the atomists disagreed, reasoning infinite worlds must exist with infinite life.
The debate's fundamental structure hasn't changed in 2,500 years - only the terms. We still have "alien optimists" and "alien pessimists." Throughout history, brilliant people argued both positions with nothing but opinions.
Then came Giordano Bruno. This radical Dominican monk accepted heliocentrism, logically concluding stars were other suns with inhabited planets. The Catholic Church wasn't amused. Bruno was burned alive at the stake. Frank notes with dark humor: "The alien debate has definitely gotten heated in the past."
In 1950, physicist Enrico Fermi asked colleagues discussing interstellar travel: "But where is everybody?" If advanced civilizations are common, they should already be everywhere. The Milky Way spans 100,000 light-years; at even fractional light-speed, civilizations could colonize it in hundreds of thousands of years - a cosmic blink compared to 13.6 billion years.
Michael H. Hart suggested absence of aliens proves we're alone - the "Great Filter" hypothesis. Others proposed the "zoo hypothesis": aliens exist but deliberately avoid us. Carl Sagan suggested spacefaring civilizations stall due to resource constraints. Frank's crucial correction: Fermi's Paradox only addresses why aliens aren't here now - it says nothing about distant signals. Humanity has searched about one hot-tub's worth of water from the entire ocean of space.
In 1961, Frank Drake created an equation revolutionizing how scientists think about alien life. The Drake Equation breaks "How many advanced civilizations exist?" into components: star formation rate, fraction with planets, habitable planets per system, probability life forms, intelligence evolves, civilizations arise, and their lifespan.
Frank emphasizes this is a clarity tool, not prediction. When formulated in 1961, only one term was known. Now we know essentially all stars have planets and about one-in-five has habitable-zone planets. In optimistic scenarios (all probabilities favorable, civilizations last billions of years), you get 200 million civilizations. In pessimistic versions, you get zero. The equation lets us see exactly where optimists and pessimists disagree.
On June 24, 1947, pilot Kenneth Arnold saw nine strange objects near Mount Rainier, traveling over 1,500 mph. He described them as moving "like a saucer skipped across water." Newspapers misquoted him as "flying saucer" - UFO culture was born in a journalistic error. Once the phrase existed, 830 flying saucer reports flooded in. People started seeing what newspapers told them to see.
Then came Roswell. Rancher W.W. Brazel found debris (rubber, tinfoil, sticks). Major Jesse Marcel announced they'd found a "flying saucer." The War Department quickly countered it was a weather balloon. The story died for thirty years.
Around 1980, researcher Stanton Friedman revived it. New claims emerged: alien bodies recovered, government cover-up. Each book added sensational details. In 1997, the government admitted covering up Roswell - but it was Project Mogul, secret balloons monitoring Soviet nuclear tests, not aliens.
he UFO circus created a "giggle factor" around serious SETI research. Scientists proposing to search for extraterrestrial intelligence faced dismissal, tarred by association with UFO true-believers and government obfuscation.
The CIA's 1953 Robertson Panel secretly concluded UFO reports- real or not- could destabilize public order. They recommended the government publicly debunk all reports for "stability." Translation: keep people ignorant for political control.
Project Blue Book investigated over 12,000 cases, finding about 11,300 explainable. Only ~6% resisted explanation—though "resisted" often meant insufficient data, not proof of aliens. Physicist Edward Condon's independent investigation (1966) concluded UFOs held nothing to interest science. The American Association for the Advancement of Science endorsed this.
Frank pivots to astrobiology. The habitable zone - where temperatures allow liquid water - is key. Not all exoplanets are equal; Drake's habitable zone defines regions where life might emerge.
Recent evidence suggests ocean moons like Europa have subsurface oceans deeper than Earth's and potential hydrothermal vents. Exoplanet discoveries show tens of thousands confirmed; one estimate suggests ten billion trillion habitable planets exist.
On alien life itself, Frank shows why carbon is special: it forms stable bonds enabling complex chemistry. Life repeatedly "invented" similar solutions - eyes, wings, locomotion evolved independently multiple times. So might aliens have sensory organs? Possibly. But details depend on planetary gravity, atmosphere, light wavelengths.
Frank's greatest strength is explaining complex concepts clearly without dumbing them down. The Drake Equation becomes intuitive. The Fermi Paradox transforms into a thinking framework. The UFO circus gains historical context.
Sections on alien consciousness, ethics, and what civilizations look like veer toward informed speculation rather than hard science. Frank labels these explorations, not predictions, but some readers may want more definitive answers. The UFO treatment, while balanced, reads diplomatically- scientifically, precious little evidence supports the extraterrestrial hypothesis. As a "brief guide," complex topics feel compressed; deeper dives require supplementary sources.
Frank's A Brief Guide to Aliens is what popular science should be: intellectually rigorous, accessible, historically informed, engaging both wonder and skepticism. He shows asking "Are we alone?" is scientifically rigorous, finally answerable with telescopes and data, not opinion. That's genuinely exciting.
Who should read this:
Anyone curious about alien life, astrobiology, exoplanets, SETI.
Those wanting contemporary science perspectives.
Readers frustrated by UFO conspiracy culture.
Scientists in astrobiology.
Students.
Anyone who loved Carl Sagan.
November 10, 2025
4.8
A fascinating read, full of thought-provoking ideas and humor. Possibly the best book about alien life (and how to search for it) that I've read
A fascinating read, full of thought-provoking ideas and humor. Possibly the best book about alien life (and how to search for it) that I've read
Displaying 1 - 2 of 2 reviews