Customer Reviews

The Accidental Universe

5 star:		(1)
4 star:		(1)
3 star:		(1)
2 star:		(0)
1 star:		(0)

 

 

Davies says the numerical values that nature has assigned to the fundamental constants--like the charge on the electron, the mass of the proton, and the Newtonian gravitational constant--are critical to the structure of the universe we perceive.

Many characteristics of systems--from nuclei to galaxies--are very sensitive to the values of the fundamental constants. Had nature chosen a slightly different set of numbers, the world would be a very different place. Most likely, we would not be here to see it.

Here's one example:

Since liquid oceans have existed on Earth for the greater part of the history of the solar system, the temperature and luminosity of the sun can't have varied very much. This long-term, stable environment is due to the sun not using up its fuel too fast.

The rate at which nuclear fuel is consumed inside a star depends on the star's luminosity. Luminosity depends on the strength of gravity, and on electromagnetism. Roughly, the lifetime of a star is given by its total energy reserves divided by the rate of energy consumption. Davies' calculations show that the lifetime of a typical star is comparable to the present age of the universe, which is correct.

From this example, we can see that if gravity were stronger, stars would burn out faster. An increase by a factor of 10 in the gravitational constant would have changed everything. The earth would no longer exist. It would have been vaporized as the sun approached its red giant phase at the end of its hydrogen consumption. Thus, the extremely long time-scale required for major cosmic change is directly attributable to the weakness of gravity.

It seems that a hidden principle is at work, organizing the universe in a coherent way. Some scientists say this principle is not a physical one, but an anthropic one. The anthropic principle takes several forms. One says that if the fundamental constants had had significantly different values, we would simply not be here to comment on them. Another edges on special creation, saying that "The Universe must be such as to admit the creation of observers within it at some stage." Still another suggests that our very special cosmos is only one example of a limitless variety of actually existing universes.

Whatever your take on the subject, this book is beautiful and awe-inspiring.

The story starts just nano-seconds after the big bang. It covers all the forces that began to shape our universe; the one that we see today. The universe evolved through different phases. There were many critical control points, where things had to be precisely correct for us to be here today. Any slight variation from the way things had to be and the universe would not resemble OUR universe in any way. Was it extremely good luck or?

P.C.W. Davies' "The Accidental Universe was one of the first popular-level discussions of the so-called Anthropic Principle (in its strong sense the idea that the universe was designed for human existence). Davies is a well-known physicist and prolific science writer.

Written almost a quarter of a century ago, this short book discuss the many seemingly accidental aspects of the universe that allow it to be life permitting, e.g. the values and relationship between the fundamental forces. I share the author view that this combination of factors is exceedingly improbable and begs the question - Why? Why do we find ourselves in a universe that appears to be improbable beyond belief? Though Davies only touches on this question in a cursory manner ,it has spawned a range of responses from scientific, religious and philosophical camps. The proposed answers run the gambit from it was designed by God - to a forthcoming Theory of Everything will make these seemingly accidental constants necessary - to science fiction type speculation regarding multiple universes. Interested readers can explore these topics in the many good subsequent works in philosophy and cosmology.

Though this is a groundbreaking small work, I do not find Davies writing style particularly engaging (he seems, however, to have improved somewhat through the years). His frequent inclusion of formulas throughout the text can make it feel very choppy. Though the math is not complex the scientific notation may unduly slow readers who are unaccustomed to this style - much of this could be included as an annex. Indeed, though Davies deserves to be recognized for his groundbreaking work others have handled this material better - many strong discussions are available within the fields of philosophy of science and the philosophy of religion.

Overall, a good little book that raises many important scientific and philosophical questions. A bit of a clumsy read at times, but, none-the-less worthwhile for those interested in cosmology or metaphysics.