Bible for the Big Bang generation

Reading this book in November, around Guy Fawkes night, constantly reminded me of one of the deeply unsatisfactory features of the cosmological theory known as the Big Bang. It is ex nihilo . At least when you see one of your own fireworks go off, and hear its report, you know who bought it, where it came from, who lit the touch paper and why it was lit at that specific time. Today's Big-Bang cosmologists squirm when asked, "What came before the Big Bang?" Usually they try to wheedle their way out of their embarrassing ignorance by claiming that the question is invalid. At the creation moment not only did matter and radiation magically spring from nothing, but time and space also appeared mysteriously from the void. To them, "time" did not exist "before the Big Bang", so the phrase is meaningless.

Today, the Big Bang paradigm is firmly engrained in the astronomical psyche. Like a well-trained choir, the world's cosmologists dutifully sing from the same hymn sheet. But it was different in the (recent) past. Then observatories and conference rooms were enlivened with discussion and dissent; data were questioned, arguments raged, tempers were lost and life was exciting.

Simon Singh treats us to a history of the past century's endeavours to understand the origin of the universe. He aims to convince the reader that we are the first generation to have a respectable, rational and coherent description for the creation and evolution of all we survey.

How things have changed! To Einstein, in 1917, the universe was small, static and eternal. In fact, Einstein went so far as to invent a cosmological anti-gravity constant to stop it all falling in on itself.

Georges Lemaitre and Alexander Friedmann disagreed. They used radioactive decay as a model and kick-started an expanding universe from a point-like primeval atom. In the late 1920s, observational data intervened. Edwin Hubble made full use of the astro-technological trinity - the largest and best telescope in the world, the most sensitive photographic plates and an accurate spectrometer. He not only discovered that the Andromeda nebula was a galaxy, but he also measured its distance from Earth. Soon he was estimating the distance to other galaxies, and measuring their velocities along the line of sight. To his amazement, the vast majority of galaxies were moving away from us; and the further away they were the faster they were going. Not only was the universe dynamic and expanding, it also had a beginning and an age.

The fact that this age was initially less than the accepted age of Earth was a slight stumbling block. Along came three Cambridge academics: Fred Hoyle, Hermann Bondi and Thomas Gold. A night at the pictures (the film was Dead of Night ) sowed the seeds of the Steady State theory. Their subsequent research was published in 1949. Here the expanding universe was continually replenished by newly created hydrogen and thus looked the same at all times and from all vantage points. Between 1950 and 1965, steady-staters and Big-Bangers battled it out. Predictions of a constant spatial density of galaxies, and young galaxies all over the place vied with a universe that was denser in the past, and had only young galaxies in its distant reaches.

Things changed in 1965. Arno Penzias and Robert Wilson published the discovery of the cosmic microwave background radiation. The fossil radio-noise remnant of the creation explosion had been discovered. This, together with the detailed understanding of the energetic nuclear physics that led to a universe that, for every 10,000 hydrogen atoms, contained 1,000 helium, 6 oxygen, 1 carbon and less than 1 of the rest, was a crippling blow to steady state theory. Finding a ripple on the background radiation also helped explain why galaxies formed in the first place as opposed to the material of the universe expanding to an ever more tenuous state.

Singh writes superbly. The concepts are well explained, and he has produced a humorous and insightful overview of the development of one of the great hypotheses of modern science. I especially liked the way in which the cast of characters, both theorists and observers, came to life. There was slightly too much reliance on secondary sources and I was unhappy to see Hoyle misquoted. (He "invented" the term "big bang", but certainly did not grace it with capital letters.) But this is a very minor quibble. As a scientist I found the book most enjoyable. It was difficult to put down.

I must also recommend this book to the non-scientist. It is an excellent introduction to the way modern science works. The Big Bang occurred on a day without a yesterday. It was unaesthetically abrupt. We are confronted with an explanation of things that previously had been in the domain of myth and religion: the proponents of the Big Bang seemingly still have a deep-rooted attachment to the first page of Genesis.

David Hughes is professor of astronomy, Sheffield University.