Reviewed by Paul Clark
This is unusual among cosmology books written for a popular audience. In most, a scientist or science writer gives an exposition of their pet theory about how and why the Big Bang happened. In this book, however, the writers give a general survey of the many different theories out there about the origins of the universe, without saying which, if any, is correct.
In the nine chapters that make up the core of the book, they describe twenty-five different sets of ideas about the origins and fate of the universe. Most of these theories suggest that ours is not the only universe, that other universes are out there in some form or other. Perhaps they exist alongside our universe, or perhaps they came before and will come after this one.
About half of the theories surveyed have cosmic inflation at their core. Seven are cyclic, with Big Bang followed by some kind of Big Crunch or, in the case of Conformal Cyclic Cosmology, the universe mathematically forgetting how big it is and having another Big Bang.
Only one theory surveyed suggests that the universe had an absolute beginning. Sixteen say the universe or multiverse is eternal, and the others leave the question open. Most theories lean heavily on quantum mechanics, with many, but not all, based on string theory.
The book discusses the methods cosmologists use. For the most part, they are trying to build mathematical models that are compatible with existing data and make predictions that can be checked. The latter criterion is fraught with difficulty, both because we lack the technology to check out many predictions, and where we can check them, we may find that two diametrically opposed theories make exactly the same prediction.
The authors lighten the tone with personal recollections and stories about the men and women who have done the most to push forward the science of cosmology.
Even so, I found the book very heavy going at times. Hardly surprising when you think how much complex subject matter the authors have to cram in. I have previously read several books on cosmology, and I am a sucker for articles and YouTube videos on the subject, but there were times when I felt overwhelmed by the denseness of the information presented. I frequently came across sentences that said, “You will recall that…” and I had no recollection whatsoever. Maybe I’m just getting old.
The only way to escape this trap would have been to write a book with less science and more analogy, I suppose, but I suspect the authors were also writing for an audience of scientists and science writers, who would have found such a book unsatisfying.
Would a good compromise have been a lighter book with a lot of the heavy stuff relegated to footnotes at the bottom of the page? Those more scientifically literate than me could dive into the footnotes and the likes of me could learn to avoid them.
Nevertheless, I’m glad I read this book because of the way the authors are willing to accept that there is so much we simply don’t know. They criticise those who take a particular model of the origins of the universe and make a premature leap to conclusions that support a particular agenda.
Among those critiqued are Christian apologist William Lane Craig and New Atheists Laurence M Krauss and Richard Dawkins. And, by implication, all those popular science writers and documentary makers who present a particular theory as truth. The whole point of this book is that we don’t know the truth about how and why our universe began. We don’t know whether ours is the only universe, how or even if it will ever end, whether it is infinite or finite, or whether it is possible to speak of “before the Big Bang”.
These may be deeply unsatisfying answers to some very big questions, but I agree with the authors that they are the answers we will probably have to live with for a very long time to come.
Paul Clark 