Prof. Pedro G. Ferreira - The Perfect Theory: A Century of Geniuses and the Battle over General Relativity

Copyright 2014 by Pedro G. Ferreira

All rights reserved

For information about permission to reproduce selections from this book, write to Permissions, Houghton Mifflin Harcourt Publishing Company, 215 Park Avenue South, New York, New York 10003.

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The Library of Congress has cataloged the print edition as follows:

Ferreira, Pedro G.

The perfect theory : a century of geniuses and the battle over general relativity / Pedro G. Ferreira.

pages cm

Includes bibliographical references and index.

ISBN 978-0-547-55489-1 (hardback) ISBN 978-0-544-26408-3 (international pbk.)
1. General relativity (Physics)History20th century. 2. PhysicistsBiography. 3. PhysicsHistory20th century. 4. ScienceSocial aspectsHistory20th century. 5. Science and civilizationHistory20th century. I. Title.

QC 173.6. F 47 2014

530.11dc23

2013021741

e ISBN 978-0-547-55490-7
v1.0214

To Gisa, Bruno, and Mia

W HEN ARTHUR EDDINGTON stood up at a joint meeting of the Royal Society and Royal Astronomical Society on November 6, 1919, his announcement quietly upended the reigning paradigm of gravitational physics. In a solemn monotone, the Cambridge astronomer described his trip to the small, lush island of Prncipe off the west coast of Africa, where he had set up a telescope and taken photographs of a total eclipse of the sun, being particularly careful to capture a faint cluster of stars scattered behind it. By measuring the positions of those stars, Eddington had found that the theory of gravity invented by British sciences patron saint, Isaac Newton, a theory that had been accepted as truth for over two centuries, was wrong. In its place, he claimed, belonged a new, correct theory proposed by Albert Einstein, known as the general theory of relativity.

At the time, Einsteins theory was already known as much for its potential to explain the universe as it was for its incredible difficulty. After the ceremony, as the audience and speakers milled around, ready to escape into the London evening, a Polish physicist named Ludwik Silberstein ambled over to Eddington. Silberstein had already written a book about Einsteins more restricted special theory of relativity and had followed Eddingtons presentation with interest. Now he pronounced, Professor Eddington, you must be one of the three persons in the world who understand general relativity. When Eddington was slow to respond, he added, Dont be modest, Eddington. Eddington looked at him firmly and said, On the contrary, I am trying to think who the third person is.

By the time I first discovered Einsteins general theory of relativity, Silbersteins count could probably be adjusted upward. It was the early 1980s, and I saw Carl Sagan on the television series Cosmos talking about how space and time can shrink or stretch. I immediately asked my dad to explain the theory. All he could tell me was that it is very, very difficult. Hardly anyone understands general relativity, he said. I was not so easily deterred. There was something deeply appealing about this bizarre theory, with its warped grids of spacetime wrapping around deep, desolate throats of nothingness. I could see general relativity at work on old episodes of Star Trek when the starship Enterprise was kicked back in time by a black star or when James T. Kirk floundered around between different dimensions of spacetime. Could it really be so hard to understand?

A few years later I went to university in Lisbon, where I studied engineering in a monolithic building of stone, iron, and glass, a perfect example of the Fascist architecture of the Salazar regime. The setting was apt for the endless lectures where we were taught useful things: how to build computers, bridges, and machines. A few of us escaped the drudgery by reading about modern physics in our spare time. We all wanted to be Albert Einstein. Every now and then some of his ideas would appear in our lectures. We learned how energy is related to mass and how light is actually made of particles. When it was time to study electromagnetic waves, we were introduced to Einsteins special theory of relativity. He had come up with it in 1905, at the tender young age of twenty-six, just a few years older than us. One of our more enlightened lecturers told us to read Einsteins original papers. They were little gems of concision and clarity compared to the tedious exercises we were being set. But general relativity, Einsteins grand theory of spacetime, was not part of the menu.

At some point I decided to teach myself general relativity. I scoured the library at my university and found a mesmerizing collection of monographs and textbooks by some of the greatest physicists and mathematicians of the twentieth century. There was Arthur Eddington, the Astronomer Royal from Cambridge; Hermann Weyl, the geometer from Gttingen; Erwin Schrdinger and Wolfgang Pauli, both fathers of quantum physicsall with their own take on how Einsteins theory should be taught. One tome looked like a big black phone book, running more than a thousand pages, with flourishes and comments from a trio of American relativists. Another one, written by the quantum physicist Paul Dirac, barely made it to a sleek and spare seventy pages. I felt that I had entered a completely new universe of ideas populated by the most fascinating characters.

Understanding their ideas wasnt easy. I had to teach myself to think in a completely new way, relying on what initially seemed like elusive geometry and abstruse mathematics. Decoding Einsteins theory required mastering a foreign mathematical language. Little did I know that Einstein himself had done the same as he tried to figure out his own theory. Once I learned the vocabulary and grammar, I was blown away by what I could do. And so began my lifelong love affair with general relativity.

It sounds like the ultimate overstatement, but I cant resist it: the reward for harnessing Albert Einsteins general theory of relativity is nothing less than the key to understanding the history of the universe, the origin of time, and the evolution of all the stars and galaxies in the cosmos. General relativity can tell us about what lies at the farthest reaches of the universe and explain how that knowledge affects our existence here and now. Einsteins theory also sheds light on the smallest scales of existence, where the highest-energy particles can come into being out of nothing. It can explain how the fabric of reality, space, and time emerges to become the backbone of nature.

What I learned during those months of intense study is that general relativity brings space and time alive. Space is no longer just a place where things exist, nor is time a ticking clock keeping tabs on things. According to Einstein, space and time are intertwined in a cosmic dance as they respond to every single speck of stuff imaginable, from particles to galaxies, weaving themselves into elaborate patterns that can lead to the most bizarre effects. And from the moment he first proposed his theory, it has been used to explore the natural world, revealing the universe as a dynamic place, expanding at breakneck speed, filled with black holes, devastating punctures of space and time, and grand waves of energy, each carrying almost as much energy as a whole galaxy. General relativity has let us reach further than we ever imagined.

There was something else that struck me when I first learned general relativity. Although Einstein took just under a decade to develop it, it has remained unchanged ever since. For almost a century, it has been considered by many to be the perfect theory, a source of profound admiration to anyone who has had the privilege of coming across it. General relativity has become iconic for its resilience, as a centerpiece of modern thought and as a colossal cultural achievement along the lines of the Sistine Chapel, the Bach cello suites, or an Antonioni film. General relativity can be encapsulated succinctly in a set of equations and rules that are easy to summarize and write down. And they are not just beautifulthey also say something about the real world. They have been used to make predictions about the universe that have since been proved by observation, and there is a firm belief that buried in general relativity there are more deep secrets about the universe that remain to be exposed. What more could I want?