Sun in a Bottle_The Strange History of Fusion and the Science of Wishful Thinking Read online

  Table of Contents

  Title Page

  Copyright Page

  Introduction

  CHAPTER 1 - THE SWORD OF MICHAEL

  CHAPTER 2 - THE VALLEY OF IRON

  CHAPTER 3 - PROJECT PLOWSHARE AND THE SUNSHINE UNITS

  CHAPTER 4 - KINKS, INSTABILITIES, AND BALONEY BOMBS

  CHAPTER 5 - HEAT AND LIGHT

  CHAPTER 6 - THE COLD SHOULDER

  CHAPTER 7 - SECRETS

  CHAPTER 8 - BUBBLE TROUBLE

  CHAPTER 9 - NOTHING LIKE THE SUN

  CHAPTER 10 - THE SCIENCE OF WISHFUL THINKING

  APPENDIX: TABLETOP FUSION

  Acknowledgements

  NOTES

  BIBLIOGRAPHY

  INDEX

  ALSO BY CHARLES SEIFE

  Decoding the Universe

  Alpha & Omega

  Zero

  VIKING

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  First published in 2008 by Viking Penguin,

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  Copyright © Charles Seife, 2008

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  LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA

  Seife, Charles.

  Sun in a bottle : the strange history of fusion and the science of

  wishful thinking / Charles Seife.

  p. cm.

  Includes bibliographical references and index.

  eISBN : 978-0-670-02033-1

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  INTRODUCTION

  Circe warned me to shun the island of the blessed sun-god, for it was here, she said, that our worst danger would lie.

  —THE ODYSSEY, TRANSLATED BY SAMUEL BUTLER

  The dream is as ancient as humanity: unlimited power. It has driven generation after generation of scientists to the brink of insanity.

  In 1905, after centuries of attempts to build perpetual motion machines, scientists discovered an essentially limitless source of energy. With his famous equation, E = mc2, Albert Einstein discovered that a minuscule chunk of mass could, theoretically, be converted into an enormous amount of energy. Indeed, E = mc 2 is the equation that describes why the sun shines; at its core, the sun is constantly converting matter to energy in a reaction known as fusion. If scientists could do the same thing on Earth—if they could convert matter into energy with a controlled fusion reaction—scientists could satisfy humanity’s energy needs until the end of time.

  For the past half century, legions of physicists have been trying desperately to create a tiny sun in a bottle, trying to bring the stellar power of fusion to Earth. The quest for fusion is the story of scientists weaving an increasingly tangled web of secret, crazy, and brilliant schemes to harness the power of the sun. They are caught up in a complex tale that includes classified government experiments, billion-dollar scientific projects, and byzantine conspiracy theories. The quest for fusion is a tale of genius physicists who have changed the world forever—for better and for worse—and of secret-spilling whistleblowers, jealous researchers, brilliant tinkerers, and backstabbing politicians.

  The stakes are enormous—and they are getting higher by the day. The world’s supply of oil is no longer assured to meet humanity’s energy needs; worse yet, the threat of global warming is forcing governments to find sources of power other than fossil fuels. In the long term, fusion is the only option. Humanity will suffer if researchers don’t solve its problems.

  Scientists have broken under the pressure. Others have been forced to make a heartwrenching decision to give up their dreams and disavow their work or to be driven from the fold of mainstream science. Over and over again, the dream of fusion energy has driven scientists to lie, to break their promises, and to deceive their peers. Fusion can bring even the best physicists to the brink of the abyss. Not all of them return.

  CHAPTER 1

  THE SWORD OF MICHAEL

  He took not away the pillar of the cloud by day, nor the pillar of fire by night, from before the people.

  —EXODUS 13:22

  The fires were still burning over Hiroshima, the charred and faceless victims were still slouching toward Asano Park, when President Harry S. Truman told the world about a new weapon. “The force from which the sun draws its power has been loosed against those who brought war to the Far East,” the announcement read. Mankind had unleashed unheard-of energy from deep within the atom and used it to destroy a city.

  From the very beginning of the atomic age, Americans were enthralled and frightened by the prospect of this inconceivable power. By splitting uranium and plutonium atoms, scientists had made a weapon by using the very same principle that made the sun shine: E = mc 2.

  The scientists who worked on the Manhattan Project, the super-secret program to build the first atom bomb, looked back on their achievement with a mix of awe and horror. To J. Robert Oppenheimer, the head of the Manhattan Project, the atom bomb represented a loss of innocence, a fall from grace that could mark the end of civilization. Others, however, such as the Manhattan Project physicist Edward Teller, saw that the atom bomb was just the beginning of a nuclear arms race. And just over the horizon, Teller realized, was a much greater weapon than even the atom bomb, one thousands of times more powerful.

  This new weapon, the “Super,” would unleash a power not yet seen on Earth: fusion. Instead of breaking a
toms apart to release energy (fission), the superbomb would stick them together ( fusion) and release even more. While this might seem to be a subtle difference, fusion, unlike fission, had the potential to produce weapons of truly unlimited power. A single Super would be able to wipe out even the largest city—a task far beyond even the bombs of Hiroshima and Nagasaki. A fusion bomb would be the ultimate weapon.

  It would also split the scientific community in two and would drive humanity to the brink of ruin. The quest to unleash the power of the sun upon the Earth had an inauspicious start, to say the least.

  The atom bombs that destroyed Hiroshima and Nagasaki were fission, not fusion, weapons. Fission and fusion are siblings. Both get their power from converting the mass at the heart of the atom into energy.

  Scientists got their first taste of that power in 1898, when the husband-and-wife team of Pierre and Marie Curie discovered a substance with a curious property. Radium, as they called it, seemed to produce energy from nothing. This was, of course, impossible. The most rigid laws of physics, the laws of thermodynamics, seemed to forbid the spontaneous creation of energy. But the Curies were quite certain of what they were observing. A hunk of radium constantly produced heat like a little oven; every hour, a chunk of radium generated enough heat to melt its own weight in ice. It would do this, hour after hour, day after day, and year after year. No chemical reaction could possibly sustain itself for so long and generate so much energy. Whenever the Curies cooled a piece of radium, it would heat itself back up. Indeed, the radium would always be hotter than its surroundings, even though there were no external sources of heat. Marie Curie herself was baffled. She suspected that some sort of change was happening at the center of the radium atom, but she didn’t know what it could be—or how such a tiny chunk of matter could produce so much energy.

  The answer would come a few years later when the young Albert Einstein formulated his theory of relativity. The theory revolutionized the way scientists perceive space, time, and motion. One of the equations that came out of the theory was E = mc2, the most famous scientific equation of all time. E = mc2 showed that matter, m, could be converted into energy, E. This was the secret to the seemingly endless fountain of energy coming from radium.

  If you put a gram of radium in a sealed ampule, over many, many years the radium (a whitish metal) will gradually disappear. In fact, the atoms of radium spontaneously split apart and vanish from view. But they don’t disappear entirely. When an atom of radium breaks apart, it tends to split into two smaller pieces. The heavier of the two is a gas known as radon; the lighter is helium, and the Curies detected both helium and radon emanating from their radium sample.

  Radium—a big heavy atom—breaks up into helium and radon, and when scientists looked carefully at the weights of those atoms, they realized the source of the heat. Some of the mass of the radium was missing. If you add up the mass of one atom of radon and one atom of helium, they make up 99.997 percent of the mass of the radium atom from which both sprang. The other 0.003 percent simply vanishes. When radium breaks apart, the parts are lighter than the original atom.

  Here was the answer to the puzzle of excess energy. The whole atom weighed more than the sum of the parts. When the radium atom spontaneously broke apart, some of its mass changed into energy, just as Einstein’s equation allows. The m had become E. The missing mass was only a tiny fraction of what made up the atom, but even tiny chunks of mass are converted into enormous amounts of energy. It was energy on a scale much, much greater than humans had ever accessed before.

  As World War II loomed, scientists began to realize that this energy could become a potent weapon. Less than a month before Germany invaded Poland in 1939, Einstein warned President Franklin Delano Roosevelt of the possibility of a bomb made from uranium, a metal that, like radium, releases energy when it breaks into pieces. Such a bomb would be extremely powerful—and there were ominous signs that the Nazis were already on their way to building one. For example, Germany had halted the uranium trade in occupied Czechoslovakia.

  Uranium—in particular, one variety known as uranium-235—is an ideal material for a weapon. Its atoms are very sensitive; hit one with a subatomic particle and it fissions into fragments. Unlike decaying radium, which tends to cleave cleanly into two parts, a fissioning uranium atom shivers into a number of smaller chunks, including a handful of neutral particles known as neutrons. These neutrons then fly away from the shattered atom.

  In a vacuum, the neutrons continue merrily on their way without bumping into anything else. However, a chunk of uranium is not a vacuum; it is a space crowded full of billions and billions of other uranium atoms. Once a single atom splits apart, within a tiny fraction of a second the resulting neutrons might slam into two or three other uranium atoms. These collisions cause those atoms to split, and in the process, each releases two or three more neutrons. All these neutrons slam into other atoms, splitting them, releasing even more neutrons. If the conditions are right—if enough uranium atoms are in a small enough space—then the process snowballs out of control in less than a blink of an eye. One atom fissions, and its neutrons cause two more to split. These cause four more to fission, causing eight to break apart, then sixteen, thirty-two, sixty-four, and so forth. After ten rounds, over two thousand atoms have split, releasing neutrons and energy. After twenty rounds, it’s more than two million atoms; after thirty rounds, two billion; after forty, more than a trillion. This is a chain reaction.

  A chain reaction, if it gets big enough, can level a city. Every time a uranium nucleus splits, it releases energy. Like radium, a uranium atom loses mass when it splits. In a tiny instant, the mass is converted into energy, just as E = mc2 predicts. The more atoms that split in the chain reaction, the more energy is released. After forty rounds of splitting uranium atoms, the energy is roughly enough to light an incandescent lightbulb for about a second. After eighty rounds, a mere fraction of a second after the chain reaction begins, the result is more energetic than the explosion of ten thousand tons of TNT, roughly the size of the blast that eventually destroyed Hiroshima.

  FISSION CHAIN REACTION: When a neutron strikes a U-235 nucleus, the nucleus splits, releasing more neutrons, which strike more nuclei, and so on.

  In 1939, though, the idea of fission—and a chain reaction that would release a tremendous amount of energy—was just a theory. Before World War II began, scientists were uncertain whether the theory was right—and if so, how to turn that theory into the hard reality of a useful weapon. It took two years of cogitation and experimentation for the consensus to build: it was possible to build a powerful bomb out of uranium-235 or plutonium-239 (an atom created in the lab by bombarding uranium with neutrons). Nuclear theory progressed quite rapidly; by 1942, the physicist Enrico Fermi was busy building the first nuclear reactor in a squash court1 at the University of Chicago. Fermi’s project was a major step toward releasing the power of the atom—and eventually bringing the wrath of the sun upon the Earth.

  The core of a nuclear reactor is little more than a controlled chain reaction: a pile of fissioning material that is not quite at the stage of entering a runaway explosion. Scientists arrange the pile so that the number of neutrons produced by splitting atoms is almost precisely the right amount to keep the reaction going without getting faster and faster; each generation of fission has roughly the same number of atoms fissioning as the last. In physics terms, the pile is kept right near critical condition. Scientists can manipulate the rate of the reaction by inserting or removing materials that absorb, reflect, or slow neutrons. Pull out a rod of neutron-absorbing material and more neutrons are available to split atoms and release more neutrons: the pile goes critical. Drop the rod back in and more neutrons are absorbed than released: the reaction sputters to a halt.

  At 3:36 PM on December 2, 1942, Fermi and his colleagues pulled a neutron-absorbing rod out of a pile of graphite and uranium oxide. The radiation counters chattered. Fermi had created the first self-sustained nuclear reacti
on. The pile had gone beyond critical; more neutrons were being produced by each generation of fission than the last. The reactor was producing more and more and more energy. About a half hour later, Fermi ordered the control rods back into the pile, and the reaction stopped. At its peak the reactor was producing about half a watt of power, almost enough to light a dim Christmas-tree lightbulb. Nevertheless, the possibilities were enormous: Fermi’s reactor showed that nuclear power could, in theory, light up a city. Or destroy it.

  It was for the latter purpose that the Manhattan Project was born. At its head was a quirky and difficult scientist, J. Robert Oppenheimer, a man who would achieve fame through fission and be destroyed by fusion.

  Oppenheimer was not an obvious choice to lead America’s race to build an atom bomb. He was a good physicist, but he was a theorist—and the Manhattan Project was, fundamentally, an engineering project. Oppenheimer was about as far from the stereotypical get-your-hands-dirty engineer as possible.

  The aristocratic Oppenheimer grew up in a wealthy family, but what was particularly striking about him was his quick mind. He mastered more than half a dozen languages, including Sanskrit. He was an adept theoretician but struggled with the more practical side of science; he had difficulty even with basic tasks such as soldering copper wires. After graduating from Harvard, he went to Cambridge in England to work in the lab of the famous experimentalist J. J. Thomson. There, the already high-strung Oppenheimer became unglued.

  Oppenheimer had a difficult time at Cambridge; in his mind, his experiments were failures, and he contemplated suicide. He also contemplated murder. In 1925, he suddenly tried to strangle a childhood friend, and his behavior got even more bizarre from there. On a vacation in Corsica with two friends, he abruptly announced, “I’ve done a terrible thing.” He said that he had poisoned an apple and put it on the desk of another brilliant physicist at Cambridge, Patrick Blackett. When everyone got back to the university, they found out that Blackett was unharmed, and Oppenheimer’s friends were left wondering whether the apple was real or just a figment of Oppenheimer’s feverish imagination.