John Gribbin - In the Beginning: After Cobe and Before the Big Bang

IN THE BEGINNING: AFTER COBE AND BEFORE THE BIG BANG

JOHN GRIBBIN

John and Mary Gribbin 1993

John and Mary Gribbin have asserted their rights under the Copyright, Design and Patents Act, 1988 to be identified as author of this work.

First Published in 1993 by Little, Brown and Company

This edition published in 2017 by Venture Press, an imprint of Endeavour Press Ltd.

Table of Contents

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Preface

Two of my main scientific interests have long been cosmology, the study of the Universe at large, and evolution, the theory which explains our presence here on Earth. During most of the twenty years or so that I have been writing books, these seemed widely disparate interests, linked only by the fact that both are subject to probing by human inquisitiveness, in the quest to find out as much as possible about both ourselves and the Universe we inhabit. But while working on my two most recent books, I became convinced that there is much more to the story of life and the Universe than meets the eye. In The Matter Myth , Paul Davies and I discussed the nature of complexity, and how simple physical laws, operating on seemingly simple physical systems, can give rise to behaviour that is more complex than the sum of its constituent parts. In In Search of the Edge of Time ( Unveiling the Edge of Time in the USA), I set out to tell the story of black holes in the Universe, and ended up being led by recent developments in cosmology to the idea that our Universe is just one among many. And then, in the spring of 1992, came news that the COBE satellite had discovered fresh evidence supporting the Big Bang theory, and the notion that the Universe was born at a definite moment in time.

The discovery acted as a catalyst, helping me to put my fumbling thoughts about life and the Universe in order. If the Universe itself was born, and will one day die, and if it is just one Universe among many, and if things are in general more complex than simple physical laws suggest, then the theory of evolution might be much more relevant to the story of cosmology than I had previously suspected. The Universe might, indeed, be alive literally, not metaphorically in its own right.

This book, which can be seen as a sequel to both Matter Myth and Edge of Time , is my attempt to explain the connection between evolution and cosmology, and to point the way to a new understanding of the Universe, an understanding being developed after COBE but which tells us what went on before the Big Bang. The ideas I describe here represent the biggest shift in our understanding of the Universe, and of our own place in the Universe, since the Big Bang theory itself was first discussed more than half a century ago. It explains how and why the Universe itself came into existence, and how and why we came into existence. You cannot really ask for much more of any scientific idea; and it all begins, as all good stories should, in the beginning with COBEs evidence for the birth of the living Universe.

John Gribbin

December 1992

Prologue - The End of the Beginning

Astronomers breathed a huge collective sigh of relief in the spring of 1992, when the most important prediction they had ever made was proved correct at the eleventh hour. The dramatic discovery of ripples in the structure of the Universe dating back almost 15 thousand million years has set the seal on twentieth-century sciences greatest achievement the Big Bang theory which explains the origin of the Universe and everything in it, including ourselves. Slotting in this missing piece of the cosmic jigsaw puzzle confirms that the Universe really was born out of a tiny, hot fireball all that time ago, and has been expanding ever since. But this is not the end of the story of cosmic creation and the evolution of the Universe. It is scarcely even the end of the beginning of that story, for this discovery also points the way to a new understanding, not just of the origin but (literally) of the evolution of the cosmos.

The story really dates back to the 1950s, when there were two rival theories to explain the nature of the Universe. Astronomers knew that the Universe contains many millions of galaxies, each one, like our own Milky Way, made up of billions of stars. (In this book, billion means a thousand million.) And they knew that these galaxies are moving away from one another, as the empty space between the galaxies expands. The simplest interpretation of this cosmic expansion is that long ago the Universe must have been much smaller, because there was less space between the galaxies. Take this notion to its limit, and you have the idea of the Big Bang that everything in the Universe emerged from a point, known as a singularity, some 15 billion years ago.

But the rival theory, known as the Steady State hypothesis, said that the Universe might have been expanding forever, without changing its overall appearance. The chief proponent of this hypothesis was the British astronomer Fred Hoyle (now Sir Fred). According to this idea, as the space between the galaxies stretched, new galaxies were continuously being created, out of nothing at all, to fill in the gaps. Of course, this would require the continual creation of new matter, in the form of hydrogen atoms, in the empty space between galaxies in order to provide the building material for the stars of new galaxies. Many scientists were horrified at the prospect; but Hoyle and his colleagues argued that this rather gentle form of continuous creation was no more abhorrent, in principle, than the notion that all of the matter in the Universe had been created in one instant, the Big Bang. Indeed, Hoyle himself coined the expression Big Bang as a term of derision for a theory that he once described as being about as elegant as a party girl jumping out of a cake.

In the 1950s, which theory you preferred was largely a matter of personal prejudice. Philosophically, is it more difficult to accept that matter is created continually in the Universe in small dribbles, or that all of the matter in all the stars and galaxies was created at a singular fixed moment in time?

The conflict between the two rival theories was resolved in the early 1960s by a dramatic and unexpected discovery. Two American radio astronomers, Arno Penzias and Robert Wilson, working with a radio antenna owned by the Bell Laboratories, discovered a weak hiss of radio noise coming from all directions in space. This radio noise, now dubbed the cosmic background radiation, was quickly explained as the remnant of the fireball in which the Universe was born, the echo of the Big Bang itself.

As the Universe has expanded for 15 billion years, the hot radiation in the original fireball has expanded with it, and cooled as a result. (This is exactly equivalent to the opposite heating effect that warms the air in a bicycle pump when you pump up the tyres of a bicycle; when things are compressed they get hot, when they expand they cool.) When astronomers measured the temperature of this radiation, they found that it was just under -270C. This is exactly the temperature the radiation ought to have if the universal expansion has proceeded since the Big Bang in line with Albert Einsteins general theory of relativity.

But there was a snag. In the 1970s and 1980s, astronomers became concerned that the cosmic background radiation is too smooth and uniform. The radiation is left over from the last phase of the Big Bang fireball, about 300,000 years after the Big Bang singularity itself. If the radiation coming from all parts of the sky is perfectly smooth, that means that the Universe was perfectly smooth just 300,000 years after the Big Bang. In a perfectly smooth Universe, as will become clear as my story unfolds, there would be no stars or planets, and therefore no people. And yet, we know that the Universe is full of galaxies, galaxies are full of stars, and stars are orbited by planets. We live on one of those planets. If the Universe were perfectly smooth, we would not exist.