Fake, fluke or pawn in a master plan?

Patrick Moore discovers that there are far more questions than answers about the scale and history of our universe.

Paul Davies is undoubtedly one of the most important modern scientific authors. Apart from his own research work, he writes for the non-specialist, but unlike most other authors of "popular" books he does not confine himself to concepts that are reasonably comprehensible; he goes much deeper.

He is well qualified to do so because, as a leading astronomer, cosmologist and theoretical physicist, he has held senior academic positions at universities in the UK and Australia and is now in America as professor at Arizona State University, the largest public university campus in the US. He has written several books that have had wide circulation and has been described as "the best science writer on either side of the Atlantic". In 2001, he was awarded the Kelvin Medal by the Institute of Physics, and the following year the Royal Society awarded him the Faraday Prize.

This new book may turn out to be his most significant contribution to date.

From our point of view, the universe is what may be termed "eco-friendly"; everything is exactly suited to us. We live in a "Goldilocks" environment (you may remember that with Goldilocks's porridge, everything had to be "just right"). But is this a mere fluke, and is it possible that we are unique?

To quote from the first chapter, "for all we know this is the first and only time anywhere in the universe that minds have glimpsed the cosmic code. If humans are snuffed out in the twinkling of an eye, it may never happen again." On the other hand, we may be an insignificant part of a scheme that is unimaginably vast. We are not considering astronomy on its own; during the past few decades we have learnt a great deal, and we are now reasonably confident that we have solved some of the problems that have been regarded as fundamental, but there is much more to be taken into account, notably religion. Putting all these together is a far from easy task, and very few writers will be able to attempt it with success.

The first sections cover topics with which many readers will be familiar.

An extremely clear account of the past history of the universe, from the big bang up to the present day, is a prelude to introducing quantum theory and terms such as the Heisenberg uncertainty principle, which are all-important in what follows. Obviously, quantum theory cannot be discussed in detail - this would require a separate book - but very sensibly these less familiar concepts are given in special boxes, and each chapter ends with a concise summary of the main points.

For example, the key points of chapter three run: "The universe as we know it began 13.7 billion years ago with a hot big bang. The universe is still expanding today, albeit at a much diminished rate, and is bathed in heat radiation. On a very large scale the universe is uniform but, at the level of clusters of galaxies and below, visible matter is clumped together. The basic structure of the universe is nicely explained by the theory called inflation. Quantum fluctuations during inflation imprinted on the universe its large-scale structure. The big bang may or may not have been the ultimate origin of the universe. If not, the question arises of what came before it."

All this is conventional enough, and even when we come to "Dark forces of the cosmos" - the mysterious dark matter that holds the clusters of galaxies together, and the even more mysterious dark energy, few readers will start to feel out of their depth. It is only with the introduction of the multiverse concept, roughly halfway through the text, that the real problems start.

According to the multiverse theory, our own universe - containing the Earth, the Sun, the stars, in fact everything in our experience - is only one of many. Some of these will be lifeless; others will be Goldilocks universes, where conditions are exactly right. We must remember that what we call the fundamental laws of nature seem as though they may well have been tailored to our needs: if they were even slightly different, we would not be here, and the most important problem discussed - in fact, the subtitle of the book - is "Why is the universe just right for life?" If these laws are different in different universes, then these places will be sterile, at least in so far as any Earth-type life is concerned. It may even be that our laws of physics may be nothing more than local bylaws.

Of course, there seems to be no conceivable way in which we can communicate with another universe, which is probably the main reason why many people, including some eminent scientists, reject the whole idea.

Worse is to come! In a science-fiction drama series presented a few years ago, the main theme was that the entire universe is a fake and the mere simulation of a gigantic computer being run by an unspecified being or beings. Surprisingly, some philosophers and even astronomers have thought seriously about this and have not dismissed it out of hand.

Davies quotes Nick Bostrom, an Oxford philosopher, as saying that "there is a significant probability that you are living in (a) computer simulation. I mean this literally; if the simulation hypothesis is true, you exist in a virtual reality simulated in a computer built by some advanced civilisation. Your brain, too, is merely a part of that simulation." On the multiverse picture, some universes will be fakes, others real.

Time travel, too, comes under scrutiny, rather more seriously than as visualised by Doctor Who or in the Back to the Future film trilogy. What are termed wormholes are said to be shortcuts between distant points in space; in a wormhole time machine, a traveller who passes through in one direction will leap into the future, while his colleague passing through in the opposite direction will leap into the past. More dramatic than an object or person making a limited visit to the past is when an object actually becomes its own past self, or loops back in time to an era before which it did not exist.

And does each universe need its own set of deities? In our own universe, established churches accept one or more supreme beings - God, or at least an intelligent designer. Recently, a cardinal in the Roman Catholic Church wrote that "scientific theories that try to explain away the appearance of design as being the result of 'chance and necessity' are not scientific at all, but an abdication of human intelligence". At the moment, serious efforts are being made to contact other intelligent beings, not in other universes, which is clearly impossible, but in our own. If we succeed - and this is by no means out of the question - one has the feeling that church leaders would be somewhat at a loss.

By this time, the average reader may start to feel that Einstein has given way to Alice in Wonderland , and that the book has abandoned science in favour of fantasy. But - and this is a measure of Davies's skill - a second reading will show that it all starts to add up and make sense, even if parts of the story are blurred.

Admittedly, the text is heavy-going, but in view of the subject matter it could not be otherwise; I doubt whether any current author could have done better, or even as well. There is a useful list of references and a good index, but one helpful addition would be a glossary of the less familiar terms used. True, the end-of-chapter summaries may be said to fill this role, but in going through the text it struck me that a glossary would help, bearing in mind that the non-specialist reader will by now be concentrating grimly.

The stated aim of the book is to answer some fundamental questions, and in particular to see if we can fathom why the universe is "just right for life" when even tiny variations in physical laws would preclude it. This is bound to lead on to associated problems. For example, we would like to know whether the universes - our universe, at least - had a definite beginning so that, as St Augustine said, "there were no earlier moments". We would like to know whether the present expansion will continue endlessly, so that the final state of the cosmos will be dark and dead, or whether the galaxies will come together in a "big crunch", possibly to start the story all over again? Above all, we are anxious to know just where we fit into the overall scenario.

The last chapter, "Aftermath: ultimate explanations", summarises the pros and cons of the various main positions dealt with in the text. Do we represent a cosmical fluke because the laws of physics happen to suit us, in which case there is no God, no designer, no technological principle, no destiny? Second, is our universe unique? Third, can we follow the multiverse theory, according to which there are many universes not in touch with each other? Or is it conceivable that our universe is a fake, and that what we take to be the real world is nothing more than an ingeniously contrived virtual reality show? Reading Davies's text will not give you the answers, but you will have a better understanding of what is involved, and this book will further enhance the author's reputation both as a writer and as a researcher.

Sir Patrick Moore is the author of more than 60 books, mainly on astronomy.