Either the universe was created expressly to be able to support living beings, or there are many universes.
This extraordinary thesis, the most exciting one of its kind since the Copernican Revolution, is starting to become fairly well-known - but I would hesitate to say it's mainstream yet. If it were, I don't think most supporters of Intelligent Design would still be wasting their time attacking the well-defended fortress of Darwinian Evolution. Instead, they would be concentrating their energies on the far more profitable area of cosmology, where the case looks better than it has for centuries, and they would all be buying copies of this book. As far as I'm aware, that's not happening. And don't get the idea that Before the Beginning
is in any way crank science or New Age mysticism. Far from it: the author is an extremely respectable observational astronomer and astrophysicist, who is doing his best to present the facts and let the reader decide for himself. There is an amusing exchange in the first few pages between Rees and Hawking that sets the tone. In the Introduction, Hawking concludes with the following passage:
... Martin and I have taken rather different courses. While I have been primarily interested in developing the theory and much of my work has not yet been confirmed by observation, Martin has always worked closely with the observations and what they tell us about the universe. I think this difference in approach is reflected in the books we have written. This one beings the reader in contact with the real stuff of astronomy - without mentioning the word God that Martin seems so uneasy with. After all, it is a theoretical concept.
To which Rees retorts:
My Cambridge colleague, Stephen Hawking, claimed in A Brief History of Time that each equation he included would halve the book's sales. He followed that injunction, and so have I. But he (or maybe his editor) judged that each mention of God would double the sales. In flattering imitation, God has figured in the titles of several subsequent books - The God Particle, The Mind of God, and suchlike. In that latter respect I shall not follow Stephen's lead. Scientists' incursions into theology and philosophy can be embarrassingly naïve and dogmatic.
True to his word, Rees makes sure that God is not mentioned again in the remaining chapters, though I'm afraid he was right: it does seem to have hurt his sales.
But enough about what the book isn't; let me tell you what it is. The first two-thirds present an overview of the relevant background from astrophysics and cosmology, as of the late 90s. It's just a little dated - in particular, there is no explicit reference to Dark Energy, which was discovered shortly afterwards - but I didn't experience this as important. Rees knows everyone and is personally familiar with most of the history. He does a great job of showing you how the key ideas evolved, starting with far-fetched hypotheses and odd observations and, in many cases, ending with detailed, coherent theories which have won general acceptance. I particularly liked his account of pulsars; I didn't realise how well-understood they now are, and that we can interpret the signals from them clearly enough that we can infer the existence of "starquakes". The topics he focuses on are galactic evolution, in particular the creation of heavy elements in stars and supernovae; neutron stars and pulsars; black holes and quasars; dark matter, and its role in the formation of the galaxies; and the very early history of the universe, where tiny quantum fluctuations created the imbalances that got the galaxies started. The greater part of this is now quite uncontroversial; he is honest about the areas that are still unclear and contentious.
Having set the scene, Rees presents his case in the last few chapters. The structure of the universe is determined by a few physical constants. There is no obvious reason why these constants should have the values they do, but, if they were only slightly different, life would be impossible. If omega, the density of the universe, were much greater, the universe would have collapsed long ago, and if it were much less then everything would have dispersed. Q, the constant which measures the large-scale "graininess", is set just right for galaxies to form. If the ratio of the strengths of the gravitational and electromagnetic forces were slightly different, long-lived stars would be impossible. The ratio of the mass of the proton to the mass of the electron is pretty much exactly what's required to permit complex molecules. If neutrinos interacted slightly differently with protons, supernovae wouldn't be able to synthesize heavy elements. There are other items. It's a startling list.
It is not out of the question that there are ways of explaining some of these "coincidences". Rees tells one illustrative story about a coincidence that fooled as great a thinker as Paul Dirac, who could not understand why the ratio of the strengths of the gravitational and electromagnetic attractions between two protons should be almost the same as the ratio of the size of a proton to the size of the universe. In fact, there is an ingenious explanation of this fact due to Dicke. But it's a lot to expect all the items on his list to be crossed off this way. His basic argument is convincing. One possibility is that the universe was designed to be hospitable to life. The other is that there are many universes, with many different settings of the physical constants. Since we are living observers, we have to be in one of the few universes that can support life.
The "multiverse" hypothesis isn't as far-fetched as it first sounds. When you trace back the history of the Big Bang, you hit this mysterious "inflationary period", when the universe suddenly got much bigger, for reasons no one really understands. Or at least, many cosmologists think so; it was interesting to read that Penrose, one of the most respected people in the field, is dubious about "inflation" and thinks it's mistaken and ugly. But, if "inflation" is correct, it could easily have created a much bigger universe than the one we see, or many universes. We don't know, and right now it's hard to think of ways to test these theories empirically. The history of science, however, is full of theories that didn't at first seem testable, but later turned out to be open to empirical verification. My gut feeling is that Rees is right: people will think of ways to do experiments.
This is a remarkably interesting book. If you're also fascinated by cosmology and have a decent grounding in high-school physics, go out and buy yourself a copy. I doubt you'll be disappointed.
I evidently wasn't paying attention - a few months before I wrote this review, Gurzadyan and Penrose published a paper
in which they claim to have found signals emanating from violent black hole collisions in a universe (possibly even several universes) which existed before the Big Bang. I don't follow their reasoning, which requires rather a rather greater understanding of General Relativity than I possess, but the claim is that these events would show up as concentric circles in the Cosmic Microwave Background radiation. The key graphic is extremely striking, and I'm surprised I haven't already seen it on a T-shirt:
Gurzadyan and Penrose estimate that the probability that this pattern could occur by chance is less than one in 10^14. Moss and Scott
write to say that the analysis is faulty, and the patterns could easily be random and don't prove anything. Gurzadyan and Penrose
reply, if I may paraphrase, that they do so prove something. The debate continues.
Damn! I am such a sucker. A bit more looking around, and I see that the Gurzadyan/Penrose idea was shot down in flames within weeks of being launched. So that's why there's been so little buzz.
I couldn't help laughing at this diagram, which I found in an article posted on The Reference Frame