Cycles of Time: An Extraordinary New View of the Universe Hardcover - 2011

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.

“The hyper-density of this book made my brain feel simultaneously wiped out and dazzled.”
            -Boston Globe Best Science Books of 2011
 
“Radical . . .  A surprising and unorthodox work disguised in the jacket of a popular science book, Cycles of Time should prove both deeply enlightening and just as deeply mystifying for anyone who dares to follow along.”
            -Peter Woit, The Wall Street Journal
 
“An intellectual thrill ride . . . As Penrose builds a solid foundation for his argument in analyzing universal entropic accumulation and Newton’s Second Law, the reader senses something tremendous looming—mysterious and compelling as a black hole . . . A cosmological page-turner.”
            -Y. S. Fing, Washington Independent Review of Books
 
“If you’ll forgive a skiing metaphor, Cycles of Time is a black diamond of a book. But like all steep slopes, sometimes you take a moment from your struggles and look up, and in front of you is an utterly gorgeous view.”
            -Anthony Doerr, Boston Globe
 
“Profound . . . This fascinating book will surely become a classic in the history of cosmology.”
            -Choice
 
“Controversial but intriguing . . . Well worth the effort.”
            -Kirkus
 
“Intriguing . . . Penrose makes provocative arguments for his challenging new theory.”                  
           -Publishers Weekly

Roger Penrose is Emeritus Rouse Ball Professor of Mathematics at the University of Oxford. He has received numerous prizes and awards, most notably the Wolf Foundation Prize in physics, which he shared with Stephen Hawking. He is the author of three previous books, including The Emperor's New Mind. He lives in Oxford, England.