Big Bang
By Simon Singh
Fourth Estate, 530 pages, $37.95
How far can you see on a clear day? This is a trick question, because on a clear day you can always see the sun, which is 150 million kilometres away. We are always accustomed to distances we can travel on earth, and few people have any idea of how far one can go "up." But on a clear night, one can see with the naked eye much farther than one can on a clear day. And yet what we see — the myriad stars — is still very near compared to what can be viewed with modern telescopes: galaxies as much as 10 billion light years away from us.
Many science writers have been inspired by the fact that the revolution in our understanding of the universe has happened within the span of a single human lifetime. Some have focused on the new technologies that made space observation possible; others have identified with the handful of dedicated scientists who have charted the galactic sky and developed scenarios to understand it.
Among these technologies, the greatest discovery came not from the development of modern telescopes but from an instrument attached to its end, the spectrograph. Spectrographs became great astronomical tools because the spectrum of light from a stellar object shows not just what this object is made of, but also, through its spectrum shifts, how fast it is moving.
By the 1930s, it was agreed that the galaxies were receding from one another, and that the speed of their recession was proportional to the distance between them. It didn't take long for some astronomers to point out that this meant that, in the past, galaxies must have been closer together and that far back in time, the universe must have started in the form of an exploding fireball — a scenario that became known as the Big Bang, and the faint echo of which we still see as television static.
Of the several people who contributed to the exploding fireball idea, probably the most imaginative — and the one generally considered the father of the Big Bang — was a Belgian priest, Father Georges Lemaître, who had joined the scientific civil service of the Church of Rome, eventually becoming its president. One would think that Lemaître's cosmological ideas would be coloured by his religious faith, and the Christian image of the Creation as described in Genesis. Not so: Lemaître was actually a very creative and careful mathematician, and proved instrumental in showing that the Big Bang model was consistent with Einstein's equations, a fact not recognized at the time even by the illustrious scientist himself.
Einstein's equations also tell us something exciting about the current expansion — that it is space itself that expands and takes the galaxies along for a ride. Also, as a final surprise, the latest total energy calculation suggests that all radiating matter — i.e. all that shines and is likely to be studied on earth — is yet a very small part of the total energy budget of the universe. There is at least 10 times more "dark matter" (which responds to and generates gravity) than there is radiative material with signals we can expect to observe.
It is no surprise that, over the years, this exciting adventure in the origins of our universe — as well as our own origins — has created an enormous library of popular science. Among several books competing this year for our attention, the most important by its size (more than 500 pages) and scope (from the Greek astronomers to the Hubble space telescope) is British broadcaster and writer Simon Singh's Big Bang.
Singh's credentials as an experienced science popularizer are impressive, as he has so far produced two bestselling TV tie-in volumes. And this book doesn't disappoint; it is engagingly written and contains all the scientific and mathematical tools necessary to construct an appealing picture of the universe and our place in it. Singh is particularly successful in describing how the constant torch-passing, from one obsessive astronomer to another, resulted in our current understanding of our extraordinarily complex, and still expanding, cosmos.
Finally, the book's illustrations are often scientific in nature and well chosen, with very useful summary notes going over the salient points of every chapter. All this helps the uninitiated, since an effort is often required to follow Singh's habit of going back and forth in time to cover different topics, rather than adopting a sequentially linear progression as we go from the Ptolemaic model to the current Big Bang theory.
Among Singh's competitors on the bookshelves this year, Neil de Grasse Tyson and Donald Goldsmith's Origins: Fourteen Billion Years of Cosmic Evolution is also an exciting volume based partly on the authors' recent PBS Nova production. Tyson, an astrophysicist and the current director of New York City's Hayden Planetarium, is an old hand at conducting popular tours of the cosmos. The book is handsomely illustrated and draws on the current cross-pollination between geology, biology, astrophysics and cosmology. Origins' aims are broader than Singh's, as the book engages in a multidisciplinary voyage through time and the cosmos, revealing what the universe has been up to — while turning part of it into our own human species.
Boris Castel is a nuclear physicist, the author of The Arts of Science and editor of Queen's Quarterly.
