Although most chemists would agree that, in its essence, chemistry is all about chemical reactions

The void 

Frank Close 

Oxford, UK: Oxford University Press 2007 | 166pp | ?9.99 (HB) ISBN 9780199225903 

Reviewed by Dennis Rouvray

Although most chemists would agree that, in its essence, chemistry is all about chemical reactions, very few chemists ever give much thought to the backdrop against which reactions occur. Chemical interactions of all kinds take place in the omnipresent medium we commonly refer to as space and more precisely spacetime. 

But what do we know about the seemingly empty void? Quite a lot actually! We know, for instance, that if all the matter is removed from some region of spacetime, are we not left with nothing. What remains is an infinite and seething cauldron of particles that are usually referred to as virtual particles. They are so designated because each of them puts in an appearance for less than a zeptosecond (10-21 second) and then promptly disappears. So-called empty spacetime is thus comprised of an effervescent quantum foam that interacts with any particles located in it. For instance, electrons passing through have their flight path altered and are caused to wobble, and the spectra of atoms are also modified via the Lamb shift. The existence of this foam even helps us to explain how our universe got started some 13.7 billion years ago at the time of the Big Bang. 

Particle physicist Frank Close offers us a welcome opportunity to get more intimately acquainted with spacetime and some of its remarkable properties. Although his work is intended primarily for a lay audience, most undergraduates - but probably not physics majors - could profit from delving into its pages. After a fairly lengthy historical introduction, Close makes reference to a number of the more pressing problems currently confronting cosmologists. These include a detailed understanding of the nature of spacetime and its inflation as the universe continues to expand, the development of a viable theory of quantum gravity, and the possible existence of multiple universes. He ends up by reminding us that everything that exists is no more than a quantum fluctuation out of nothing. 

All in all, this book makes for some fascinating reading though it contains no really new ideas and is less comprehensive than other works on this topic, such as John Barrow’s The book of nothing. But it does provide a good place to start for anyone wishing to learn something about the structure of spacetime and the origin of our universe.