Alone in the Universe: Why Our Planet is Unique – Book Review

Book Review by Cory Davis

This is a book review of author John Gribbin’s “Alone in the Universe: Why Our Planet is Unique” (2011) published by John Wiley & Sons Inc. out of Hoboken, New Jersey, originally published by Penguin Books Ltd. In Great Britain.


“Alone in the Universe  will make for interesting conversations and leave you awake at night pondering our fragile existence and place in the cosmos.”

Alone in the Universe -- Why Our Planet Is Unique.jpg
Alone in the Universe by John Gribbin Book Cover

About the Author

John Gribbon is a visiting fellow in astronomy at the University of Sussex, UK with a PhD in Astrophysics, M.Sc. in Astronomy and B.Sc. in Physics. Notably, John Gribbin worked as a research student for Fred Hoyle, a famous scientist known for developing the theory of stellar nucleosynthesis and opposition of the big bang, in favour of the steady state model.

However, he is most well known for being a science communicator who wrote many books including “Before the Big Bang”, “In Search of Schrödinger’s Cat: Quantum Physics and Reality”, and “Richard Feynman: A Life of Science”.

What the Book is About

First and foremost, “Alone in the Universe” is not an argument that we are literally alone in the universe. It is an argument that we are alone as a technological civilization in the Milky Way Galaxy. It answers the Fermi Paradox, which is essentially, if technological civilizations are common, then “Where are they?”. Perhaps using Occam’s Razor, the most-simplest explanation is that technological civilizations are not common, and they are not here.

Along the same vein as “Rare Earth: Why Complex Life is Uncommon in the Universe” By Peter Ward and Donald Brownlee, this book explores the conditions and series of events that made complex life possible here on earth, and the many possible ways it could have gone sideways if it occurred slightly differently.

Indeed, the universe is a violent inhospitable place for life, and even more so for complex life. The series of events that led to the fragile state of conditions we currently inhabit were very unlikely. Earth could have easily turned out differently. If we ran the clock back and changed the initial conditions only slightly, we may not be here today to talk about it.

The book is structured into eight chapters. The first chapter felt like an argument that life is common. He does this throughout the book, giving the reader support for an opposing view, before arguing against it. The second chapter is about the Milky Way Galaxy and its habitability. He does go beyond the Milky Way at times, noting that not all galaxies are habitable. Just based on metallicity alone, we can conclude that most galaxies are not very accommodating to technological life. The third chapter talks about the stars and their influence on life in worlds that orbit them. The fourth chapter focusses on factors that influence the habitability of solar systems, such as orbits and the influence of large Jupiter-like planets in different locations within them. The fifth chapter is dedicated to the conditions of earth such as plate tectonics and how they influence habitability making comparisons to other planets such as Venus and Mars. The sixth and seventh chapters are dedicated to evolution, highlighting the fact that it is not goal-oriented (intelligent technological life is not a goal of evolution), rather it is a series of adaptations to changing environmental conditions, which vary over time differently in various locations on earth. Here, the author also highlights the several unlikely events throughout our evolutionary history that led to complex life. The last chapter focusses on us as a technological civilization, why it is a unique feature and the possibility of it occurring again.

All eight chapters support the final conclusion: that we are alone in the galaxy. Not that technological life never existed before in the galaxy, or that it won’t happen again sometime in the future. He is not arguing that we are alone in the universe. He is arguing that in the short sliver of time that we exist, it is highly improbable that another technological civilization inhabits the Milky Way at this particular moment.

What I Liked About the Book

Alone in the Universe communicates science in an easily digestible way. It outlines a suite of scientific information to provide context to the inferences used to establish the premises of the author’s argument.

The argument itself is thorough. From the chemical structure of the galaxy, planetary orbits, rotation, and tilt, to the evolutionary circumstances that resulted in our civilization, orientated in the vast expanse of time, it is clear to see that complex, technological life like ours is relatively rare.

There were many moments throughout the book where my mind was racing. Excited, I stayed up at night pondering our existence and what earth would be like if pivotal moments in our evolutionary or cosmic history went slightly different. This is why I gave this book such a high rating. It was fun and it engaged the reader, giving me lots to think about.

Whether you agree with the conclusion or not, that we are alone in the Milky Way Galaxy as a technological civilization, the argument itself makes for a fun thought experiment that will fuel interesting conversations on topic.

Alone in the Universe makes for an excellent addition to the Fermi-Paradox and Rare Earth Hypothesis compendium, putting forth an argument for why it may be the case that intelligent life in the universe is exceedingly rare.

What I Disliked About the Book

The argument itself was not summed up in an easily accessible way. After reading the book, I will have to go back through all my notes to summarize the argument. The end of the book does not do this for you, which was disappointing. After getting through the whole book, it just would have been really nice to sum it up in a one-or-two-page reflection piece to really hit the message home.  

The introduction was initially bland. It talked generally about the milky way, how big it is, how many stars there are and so forth. It talked about the observable universe and how many galaxies there are, how many light years accross it is, etc. He states that we can see a diameter of 27 light years or so, because the universe is about 13.8 billion light years old. I was getting bored because this is old news. However, those new to the topic, could find it to be a feature, rather than a bore.

As I kept reading though, I started to find gems of knowledge that were new to me. For example, did you know that the first direct evidence that planets form out of clouds of debris was around a pulsar? Pulsars form from stars much larger than the sun who go supernova. Some of these stars, if they are big enough, form black holes. But if not, they can form pulsars, neutron stars or possibly other exotic forms such as quark-stars. Apparently, some planets cannot survive a supernova, the event is much too violent. However, researchers Alex Wolszczan and Dale Frail of Penn State University found planets orbiting a pulsar that could not possibly have survived a supernova. Therefore, the planets were formed out of the material discharged from the supernova explosion. My mind is blown.

There were a couple times I was lost in the book, having to re-read paragraphs to try to understand what he was saying or why it supports his argument. This mostly occurred in the last few chapters, where the material became a little more complex.

The book is structured well, but it did not come together for me in the end.  My four main criticisms are a follows:

  1. I would have appreciated a diagram or summary of the argument. Each chapter was like a premise leading the reader toward a conclusion. The end of the book does not summarize the argument for you. You need to take notes and formulate his argument yourself.
  2. Some of the premises did not necessarily lead to the conclusion as there are still so many unknown variables. All in all, it was a strong argument, but the conclusion was extreme. I think a fairer conclusion would have been “therefore, the probability that more than one technological civilization exists in the Milky Way Galaxy at this precise moment in time is very low”, rather than “we are (authoritatively and definitively) alone in the Milky Way Galaxy”.
  3. The book was not written very purposefully. I understand that the purpose is to argue that we are alone in the galaxy, but why is this important? He indicates that the earth is fragile so we should probably take care of it, but is this why he wrote the book? That is not clear. In my opinion, the book should have had one final chapter, that sums up the argument and outlines why we should care. What is the agenda? Should we defund SETI (the Search for Extraterrestrial Intelligence)? Should we save the planet? Does the conclusion that life is rare indicate some kind of greater responsibility for humanity? What is the point of this book and why is it important? I would have appreciated some ending that drove the message home.
  4. The conclusion is not that we are “Alone in the Universe”, it is that we are alone in the Milky Way Galaxy. He makes this clear when you read the book, but the cover is dishonest, like a catchy title to lure the reader in.

For the above four reasons, my rating was reduced from 5 stars to 4 stars.


I really enjoyed reading this book and recommend it to anyone curious about the subject, especially for those who hold opposing views. If anything, it will inform you of the other side to an argument that you may not have heard explained in depth before. Enter it with an open mind, make notes and develop a more substantiated opinion of the topic, even if you don’t reach the same conclusion. Alone in the Universe  will make for interesting conversations and leave you awake at night pondering our fragile existence and place in the cosmos.

If you are curious about life in the universe, and our place within it, then this is a must read. But this is not the only book I would recommend on the subject. Below are some books and audiobooks that I thoroughly enjoyed on the topic and would recommend to anyone who is interested in no particular order:

  1. Rare Earth: Why Complex Life is Uncommon in the Universe by Peter Ward and Donald Brownlee
  2. Lucky Planet by David Waltham
  3. The Eerie Silence by Paul Davies
  4. Aliens: The Worlds Leading Scientists on the Search for Extraterrestrial Life by Jim Al-Khalili
  5. The Contact Paradox: Challenging Our Assumptions About the Search for Extraterrestrial Intelligence
  6. The Copernican Complex: Our Cosmic Significance in a Universe of Planets and Possibilities by Caleb Scharf
  7. Goldilocks and the Water Bears by Louisa Preston
  8. Light of the Stars by Adam Frank
  9. Confessions of an Alien Hunter: A Scientist’s Search for Extraterrestrial Intelligence by Seth Shostak
  10. All These Worlds Are Yours: The Scientific Search for Extraterrestrial Life by John Willis
  11. Extraterrestrial Intelligence by Jean Heidmann

If you would like me to revisit any of these for a review or breakdown, please let me know in the comment section below.

Thank you so much for reading my review for Alone in the Universe by John Gribbin. I found this material super interesting. But I am more interested to hear your thoughts and opinions. If you have any thoughts about life in the universe, or comments about this book, please share them below. I promise to read them, and am sure they will make for interesting dialogue.

If you enjoyed this post, please give it a like or subscribe. You can also follow me on twitter @interestpeaks. Please stay tuned! In my next post, where I will break down the author’s argument for why we are alone in the Milky Way Galaxy.

2 thoughts on “Alone in the Universe: Why Our Planet is Unique – Book Review

  1. Pingback: “Alone in The Universe”: John Gribbin’s Argument for Why Most of the Milky Way Galaxy is Uninhabitable – Interest Peaks

  2. Pingback: “Alone in The Universe”: John Gribbin’s Argument for Why Most Star Systems in the Milky Way are Uninhabitable | Interest Peaks

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