Big Bang: The Most Important Scientific Discovery of All Time and Why You Need to Know About It

  • Simon Singh
Fourth Estate: 2004. 544 pp. £20, $27.95

When the British astrophysicist Fred Hoyle coined the phrase ‘Big Bang’ to describe the rival to his beloved ‘steady state’ theory of the Universe, he meant it to be disparaging. It was bad enough for Hoyle that his pet theory turned out to disagree with astronomical observations, but it must have been especially galling that his cosmological adversaries embraced his derisive name. The tag has since spread into the wider cultural domain — nowadays even politicians have heard of the Big Bang.

But what is the Big Bang? In a nutshell, it is the idea that our Universe — space, time and all its matter content — was born in a primordial fireball, from which the whole caboodle has been expanding and cooling ever since. Pioneering theorists such as Aleksander Friedmann and Georges Lemaître derived mathematical solutions of Einstein's field equations that could be used to describe the evolution of a Big Bang Universe. These models involve a creation event, in which space-time and matter-energy sprang into existence to form our Universe. We are still in the dark about how this happened, but we think it took place about 14 billion years ago.

Edwin Hubble's discovery of the recession of distant galaxies gave support to the idea that the Universe was expanding, but the notion that it might be evolving from a hot beginning was rejected by many theorists, including Hoyle. He favoured a model in which the origin of matter was not a single event but a continuous process in which atoms were created to fill in the gaps created by cosmic expansion. The battle between these competing views of creation raged until the accidental discovery in 1965 of the cosmic microwave background radiation, which marked the beginning of the end for the steady-state theory.

This conflict between the two theories plays a central role in Simon Singh's book Big Bang. His previous books, Fermat's Last Theorem and The Code Book, succeeded admirably in bringing difficult mathematical subjects to a popular readership, using a combination of accessible prose, a liberal sprinkling of jokes and a strong flavouring of biographical anecdotes. The recipe for his new book is similar.

In Big Bang, Singh uses the historical development of modern cosmological theory as a case study for how scientific theories are conceived, and how they win or lose acceptance. He rightly points out that science rarely proceeds in an objective, linear fashion. Correct theories are often favoured for the wrong reasons; observations and experiments are frequently misinterpreted; and sometimes force of personality holds sway over analytic reason. Because cosmology has such ambitious goals — to find a coherent explanation for the entire system of things and how it has evolved — these peculiarities are often exaggerated. In particular, cosmology has more than its fair share of eccentric characters, providing ample illustration of the role of personal creativity in scientific progress.

This very well written book conveys the ideas underpinning cosmological theory with great clarity. Taking nothing for granted of his readership, Singh delves into the background of every key scientific idea he discusses. This involves going into the history of astronomical observation, as well as explaining in non-technical language the principles of basic nuclear physics and relativity. The numerous snippets of biographical information are illuminating as well as amusing, and the narrative is driven along by the author's own engaging personality.

As a fan of Singh's previous books, I have to admit that, although this one has many strengths, I found it very disappointing. For one thing, there isn't anything in this book that could be described as new. The book follows a roughly historical thread from pre-classical mythology to the middle of the twentieth century. This is a well-worn path for popular cosmology, and the whole thing is rather formulaic. Each chapter I read gave me the impression that I had read most of it somewhere before. It certainly lacks the ground-breaking character of Fermat's Last Theorem.

The past ten years in cosmology have witnessed a revolution in observation that has, among many other things, convinced us of the existence of dark energy in the Universe. Theory has also changed radically over this period, largely through the introduction of ideas from high-energy physics, such as superstring theory. Indeed, some contemporary Big Bang models bear a remarkable resemblance to the steady-state universe, involving the continuous creation not of mere atoms, but of entire universes.

Frustratingly, virtually all the exciting recent developments are missing from this book, which leaves off just when things started to get interesting, with the COBE satellite in 1992. Readers who want to know what is going on now in this field should definitely look elsewhere. The processes of cosmic discovery and controversy are ongoing, not just relics of the past.