Top positive review
Frees the mind to think about the unknowable
on May 3, 2000
This is an exciting and accessible book of cosmological speculation tempered by rationality and an awareness of the scientific method. Consequently I was very happy to read here about the possibility of "universes" beyond ours; or differently put, something beyond the big bang. I ed to speculate about what happened before and beyond the big bang, but I was told that such speculations were unscientific because by definition the universe and all of time and space came into being with the big bang. Like Fred Hoyle, I never liked this theory of the beginning of the universe, and wished that his steady state model would gain some serious credence. It didn't and the evidence for the big bang grew. Now however, as Rees makes clear, the perspective and even the terminology has changed. Many scientists now speculate that our universe (notice we now have an "our") may just be a budding off of one "universe" from perhaps an infinite potential.
One page 158 Rees writes about the universe at the Planck time (ten to the minus 43 seconds) which is as early as we can get, and incidentally the universe at that time was as small as anything can get: "At this stupendous density...quantum effects and gravity would both be important. What happens when quantum effects shake an entire universe?"
Now that is a question! And the way it is put propels us into something like a glimpse of the universe at that ultra early stage. The Planck time is a constraint on the size of anything including space. One of the things that this means is that spacetime is not infinitely divisible. Space itself has a quantum-like quality. Really?
On page 24 he is talking about communicating with other intelligent beings: "It would be easy to devise signals that would be incontrovertibly artificial: for instance, attention could be attracted by a series 1,3,5,7,11,13,17,19,23,29... These are prime numbers: no natural process could generate them, but they would be recognized by any culture that was interested in (and capable of) picking up cosmic radio waves." Notice how simply but beautifully put this observation is.
On the same page he makes the point that even though we might get some startling advice from a more advanced civilization, there is some question about whether we would follow it, or even if we could benefit from it. He writes: "Optimists claim that such signals could convey enlightening messages of such import that they would enable us to bypass centuries of scientific endeavor and discovery... But such a gap would be hard to bridge, even within human culture. Could, for instance, a short 'message from the future' have guided a leading intellect from an earlier era toward some aspect of modern scientific knowledge? Could Newton have been steered from alchemy toward chemistry...? It would be a daunting challenge to bridge even a few centuries of human cultural change, essentially because scientific advance depends on gradual advances of interconnected techniques and technologies."
I was delighted to find on page 161 my favorite "Zen koan" question, "Why is there anything at all? Why isn't there nothing?" being asked in a slightly different form by Stephen Hawking: "What is it that breathes fire into the equations?...Why does the Universe go to all the bother of existing?" In my opinion, it is a question like this that makes the study of cosmology so compellingly religious. I stopped being concerned with the question of whether God exists or not when I realized how incredibly vast is the known universe that beings superior to us almost certainly must exist and therefore it would be only a matter of degree to get to some being approximating the anthropomorphic conception of "God." That there are demigods out there is clear. That there are demigods who could pass for God among humans is also clear. As for a creator or a first cause, or any sort of nonpersonal "God," the Universe itself is sufficient. So, strangely, I became a deist of sorts. Still on page 161, Rees makes the very important distinction between the physicist's vacuum (which is actually a "rich construct," including "all the particles and fields described by the equations of physics") and the philosopher's "nothing," which really is nothing. Now that I think about it, however, maybe that sort of "nothing" is not even possible, just a philosopher's construct.
Notice that what is wonderful about Rees's book is how freeing it is instead of confining. The mind soars. If his intent was to communicate to a large audience I believe he has succeeded. This is the most informative and readable book on cosmology that I have read in quite a while.
One last speculation: suppose that instead of the expansion of spacetime, we have the implosion of matter, that is to say, instead of having the universe expand, we have matter shrink. Is it possible to tell the difference? Although this may seem frivolous, and perhaps it is, asking such a question has the virtue of engaging the mind, which is what Rees does in this book.