Cycles of Time An Extraordinary New View of the Universe

by Penrose, Roger

• ISBN13: 9780307278463
• ISBN10: 0307278468
• Edition: Reprint
• Format: Paperback
• Copyright: 2012-05-01
• Publisher: Vintage

Summary

From the best-selling author of The Emperor's New Mind and The Road to Reality, a groundbreaking book that provides new views on three of cosmology's most profound questions: What, if anything, came before the Big Bang? What is the source of order in our universe? What is its ultimate future? Current understanding of our universe dictates that all matter will eventually thin out to zero density, with huge black holes finally evaporating away into massless energy. Roger Penroseone of the most innovative mathematicians of our timeturns around this predominant picture of the universe's "heat death," arguing how the expected ultimate fate of our accelerating, expanding universe can actually be reinterpreted as the "Big Bang" of a new one. Along the way to this remarkable cosmological picture, Penrose sheds new light on basic principles that underlie the behavior of our universe, describing various standard and nonstandard cosmological models, the fundamental role of the cosmic microwave background, and the key status of black holes. Ideal for both the amateur astronomer and the advanced physicistwith plenty of exciting insights for each Cycles of Time is certain to provoke and challenge. Intellectually thrilling and accessible, this is another essential guide to the universe from one of our preeminent thinkers.

Author Biography

Roger Penrose is Emeritus Rouse Ball Professor of Mathematics at Oxford University. He has received a number of prizes and awards, including the 2020 Nobel Prize in Physics for his work on black hole formation, as well as the 1988 Wolf Prize for physics, which he shared with Stephen Hawking for their joint contribution to our understanding of the universe. His books include Cycles of Time, The Road to Reality, The Nature of Space and Time, which he wrote with Hawking, and The Emperor’s New Mind. He has lectured extensively at universities throughout America. He lives in Oxford.

Table of Contents

Preface	p. ix
Acknowledgements	p. xi
Prologue	p. 1
The Second Law and its underlying mystery	p. 9
The oddly special nature of the Big Bang	p. 57
Conformal cyclic cosmology	p. 137
Epilogue	p. 220
Appendices	p. 221
Notes	p. 252
Index	p. 273
Table of Contents provided by Ingram. All Rights Reserved.

Excerpts

PREFACE

One of the deepest mysteries of our universe is the puzzle of whence it came.
 
When I entered Cambridge University as a mathematics graduate student, in the early 1950s, a fascinating cosmological theory was in the ascendant, known as the steady-state model. According to this scheme, the universe had no beginning, and it remained more-or-less the same, overall, for all time. The steady-state universe was able to achieve this, despite its expansion, because the continual depletion of material arising from the universe’s expansion is taken to be compensated by the continual creation of new material, in the form of an extremely diffuse hydrogen gas. My friend and mentor at Cambridge, the cosmologist Dennis Sciama, from whom I learnt the thrill of so much new physics, was at that time a strong proponent of steady-state cosmology, and he impressed upon me the beauty and power of that remarkable scheme of things.
 
Yet this theory has not stood the test of time. About 10 years after I had first entered Cambridge, and had become well acquainted with the theory, Arno Penzias and Robert Wilson discovered, to their own surprise, an all-pervading electromagnetic radiation, coming in from all directions, now referred to as the cosmic microwave background or CMB. This was soon identified, by Robert Dicke, as a predicted implication of the ‘flash’ of a Big-Bang origin to the universe, now presumed to have taken place some 14 thousand million years ago—an event that had been first seriously envisaged by Monsignor Georges Lemaître in 1927, as an implication of his work on Einstein’s 1915 equations of general relativity and early observational indications of an expansion of the universe. With great courage and scientific honesty (when the CMB data became better established), Dennis Sciama publicly repudiated his earlier views and strongly supported the idea of the Big Bang origin to the universe from then on.
 
Since that time, cosmology has matured from a speculative pursuit into an exact science, and intense analysis of the CMB—coming from highly detailed data, generated by numerous superb experiments—has formed a major part of this revolution. However, many mysteries remain, and much speculation continues to be part of this endeavour. In this book, I provide descriptions not only of the main models of classical relativistic cosmology but also of various developments and puzzling issues that have arisen since then. Most particularly, there is a profound oddness underlying the Second Law of thermodynamics and the very nature of the Big Bang. In relation to this, I am putting forward a body of speculation of my own, which brings together many strands of different aspects of the universe we know.
 
My own unorthodox approach dates from the summer of 2005, though much of the detail is more recent. This account goes seriously into some of the geometry, but I have refrained from including, in the main body of the text, anything serious in the way of equations or other technicalities, all these being banished to the Appendices. The experts, only, are referred to those parts of the book. The scheme that I am now arguing for here is indeed unorthodox, yet it is based on geometrical and physical ideas which are very soundly based. Although something entirely different, this proposal turns out to have strong echoes of the old steady-state model!
 
I wonder what Dennis Sciama would have made of it.