The Constants Of Nature [Paperback]

This is an enjoyable read packed from cover to cover with thought provoking ideas and concepts. On completing the book this reader was left with a greater appreciation of the men and women who have added to the sum total of scientific knowledge. It came as a surprise to me that some of these giants of science had led rather unhappy lives, in some cases resulting in severe depression and worst case suicide. The author successfully argues that if the constants of nature of the title were even marginally different than those measured by Physicists today then there would be no life as we know it in the Universe. The fine structure constant features large in the text. It came as quite a shock to learn of a prehistoric nuclear reactor in Gabon, West Africa and that around two billion years ago other such reactors probably existed. This discovery had slipped under my radar. Further, while it is thought that there has been no change in the value of the fine structure constant over the last two billion years,this may not be the case prior to that time in the life of the Universe. While there is some mathematical content it should not put off the non-specialist. However, in my paper-back copy the printer has used the letter 'I' rather than the numeric '1'. So 1915 reads I9I5. Not a big problem but some care is needed when reading equations. Additionally Figure 11.6 referenced on page 243 is missing. The final chapter of the book is given over to speculation on what may exist beyond the currently observable Universe. Much of this I found to be disconcerting. The value of theories that cannot be tested experimentally must be questionable. However it is facinating to learn of some of the current ideas in Cosmology. Highly recommended.

I bought this book to get an update on cosmology and Barrow certainly has a spellbinding story to tell about the constancy of the universe and several what-if scenarios on how tiny changes in the essential constants governing the structure of space. I knew nothing about the anthropic principle but readning the book I went from scepticism due to the potential misuse from non-scientist camps (ie intelligent design) but finally rendered myself and know consider myself at least avidly interested in the debate on that particular subject on the Internet.

The historical thread through the book on how famous physisists have grapppled with constancy is written in an engaging tone and
ties well into the rest of the book.

In order to explain physical reality, physicists measure and determine physical quantities/parameters/information related to the object/subject in question using well defined laws such as; the laws of classical physics (theory relativity), quantum mechanics, and thermodynamics. Physicists do not know the details of all the laws, and their interpretations/explanations often vary, but the physical laws themselves are the same across the universe. Einstein's principle of covariance states that laws of nature should appear the same for all observers in the universe no matter where they are located or how they are moving. The equations and the fundamental constants that write these laws are universal, but as physicists try to explain how the universe works, it is increasingly becoming apparent to a few physicists that some fundamental constants such as the speed of light (c), fine-structure constant, proton-electron mass ratio, and gravity (G) have changed over the last 13.7 billion light years.

The author chronicles the historical development in the physics research of universal constant and touches upon the most fundamental part of creation. How do these constants that are a part of an equation could have impacted a functional universe that supports life? Mathematician Ramanujan once said that "An equation has no meaning unless it expresses the thought of God." The dimensionless constant is certainly the thought of God. Time variation of fundamental constants is subjected to theoretical and experimental research by a number of physicists such as; Arthur Eddington, Paul Dirac, George Gamow, Robert Dicke, Brendan Carter and others. The fine-structure constant was originally introduced in 1916 by Arnold Sommerfeld, as a measure of the relativistic deviations in atomic spectral lines of the Bohr's atomic model. This constsnt is interpreted as a measure of electromagnetic force that holds the atoms together or the strength of the interaction between electrons and photons; the ratio of two energies, the energy needed to bring two electrons from infinity to a distance against their electrostatic repulsion, and the energy of a single photon. It is also defined as the ratio of the strengths of the electromagnetic and gravitational interactions. This constant is a dimensionless quantity (1/137.035999679); hence its numerical value is independent of the system of units used. Many physicists have wondered why God would have created such an odd number for this constant (value of Pi is another example.) One explanation is the cosmological evolution of a quintessence-like scalar field coupled to gauge fields and matter would have effectively modified the coupling constants and particle masses over time. However, the anthropic principle states that the value of the fine-structure is what it is because stable matter could not have existed in the universe if that was any other number. In other words, galaxies, stars, planetary systems and life forms would not have evolved. For instance, if this constsnt was changed by 4%, carbon and oxygen would not have been produced in stars.

Since fine-structure constant is present wherever electromagnetism is, it is determined by various methods from atomic spectra. One is by analyzing the atomic spectra of distant galaxies and stars. The second one is the natural reactor of Oklo has been used to check if the atomic fine-structure constant might have changed over the past 2 billion years. That is because it influences the rate of nuclear reactions. For example, Samarium(149) captures a neutron to become Samarium(150), and since the rate of neutron capture depends on the value of this constant, the ratio of the two samarium isotopes in samples from Oklo can be used to calculate the value of this constant that existed 2 billion years ago. The results are conflicting and it is not clear if these constant are changing. Despite the fact that this book has many irrelevant quotations from unorthodox figures such as; Joan Rivers, Woody Allen, Brooke Shields, W.C. Fields, and George Bush, it is highly recommended.