Sun in a Bottle

by Charles Seife

  Pons and Fleischmann’s setup was supposedly making an end run around physics’ requirements for fusion. There was no attempt to heat the deuterium to millions of degrees or to compress it to high densities. The chemists merely took a little rod of palladium metal, plopped it in a jar full of deuterium-enriched water, and ran an electric current through it. Somehow, without the benefit of high temperature and high pressure, the deuterium atoms were fusing inside that metal.

  Though cold fusion seemed ridiculous, physicists could not dismiss the idea out of hand. It was possible, if unlikely, that palladium metal could somehow force the deuterium nuclei into contact. Pons and Fleischmann could possibly have found a new and fortuitous physical effect that nobody had anticipated. It had happened before. In fact, it had happened before to Fleischmann.

  In 1989, Fleischmann was a well-respected English chemist. He had been a key player in the field of electrochemistry, the study of chemical reactions that occur because of the influence of electric currents. He had made his name, in part, by discovering a useful physical effect that nobody had predicted—or, at first, believed. In the early 1970s, he used lasers to detect the presence of a minute amount of a chemical on a piece of silver, even though conventional wisdom said that his results were impossible. The chemical should have been all but undetectable by the technique he used. But Fleischmann was correct; he had done the seemingly impossible. He had unwittingly discovered an effect that would be called surface-enhanced Raman scattering, a phenomenon that is now used in a variety of sensitive chemical detectors. Conventional wisdom was wrong and Fleischmann was right.

  The scientific community soon rewarded Fleischmann for his discovery. In the mid-1980s, he was made a Fellow of the Royal Society, the highest honor that Britain bestows upon its scientists. By the late 1980s, his reputation made him welcome at scientific institutions around the world. He spent most of his time hopping between laboratories at his home university in Southampton, the Harwell laboratory (of ZETA fame), and a lab at the University of Utah.

  Stanley Pons was the chair of the University of Utah’s chemistry department, and the two had a long history together. Fleischmann had taken the younger Pons under his wing in the mid-1970s when Pons was at Southampton. Long after Pons moved back to the States the two kept working together. Fleischmann, the elder statesman, and Pons, the eager young experimentalist, made a good team, producing an enormous amount of research. Pons was particularly prolific. By the late 1980s, he was publishing several dozen papers per year. This was a huge output, and it could be argued that the frantic pace led to careless work. Indeed, over the years, Pons and Fleischmann had published some papers that seemed ludicrous—such as one that involved highly unlikely reactions of nonreactive gases—but the two still maintained a good reputation. This is part of the reason that cold fusion got so much attention. Pons and Fleischmann were established scientists; they were not no-name amateurs like Ronald Richter had been. So when they announced their cold-fusion results in 1989, even skeptical physicists took the claim seriously.

  The cold-fusion experiment was deceptively simple. At the heart of each “reactor” was a rod or a sheet made of palladium. Palladium is a whitish metal that shares numerous properties with platinum and nickel. Oddly, it is able to soak up enormous volumes of hydrogen—the tiny hydrogen atoms nestle between the atoms of palladium—so researchers had been studying the metal in hopes of coming up with a method for storing hydrogen in fuel cells.

  Pons and Fleischmann had long been intrigued by this hydrogen-sponging behavior. They mused about it—talking while driving across Texas, talking while hiking along a canyon—wondering aloud about what was happening to the hydrogen that was crammed inside the palladium. Perhaps the hydrogens were very crowded in the small spaces between the palladium atoms. Perhaps those spaces were so crowded that the hydrogen atoms were bumping into each other with great force. Perhaps, if the hydrogen was replaced with deuterium... It was a crazy idea, but it just might work. If the pressures inside a palladium cage were high enough, they might just induce fusion in a way that a laser cage or a magnet cage could not. Sitting in Pons’s kitchen, the two devised an experiment to discover whether palladium fusion was possible. No law of nature said it was impossible to induce fusion inside a metal cage. It was worth a try, anyhow.

  At first, they spent their own money, about $100,000 for the first crude experiments. “Stan and I thought this experiment was so stupid we financed it ourselves,” Fleischmann said at the press conference. But by scientific standards, their experimental setup was not that expensive, so it was a worthwhile risk to try, even on their own dime. Sometime in 1984, at least according to their own timeline, they took a chunk of palladium and set it in heavy water, water whose two hydrogen atoms are replaced with deuterium. To the water they added a salt containing lithium and deuterium. Then they stuck in a platinum wire and hooked it and the palladium up to a battery. They hoped that over time the current would cause deuterium to seep into the palladium, where the deuteriums would then begin to fuse. But when Pons and Fleischmann started the experiments, nothing happened. Then, one day, they cranked up the juice and left for the evening. Fleischmann told the Wall Street Journal what happened next:

  Sometime during the night the palladium cube suddenly heated up to the point where some of it vaporized, blowing the apparatus apart, damaging a laboratory hood and burning the floor. “It was a nice mess,” Mr. Pons said. A check of the laboratory the next day with a radiation counter indicated radioactivity levels three times higher than the normal background levels, apparently the result of a sudden spray of neutrons.52

  Pons and Fleischmann took this as a clear sign of fusion. Only a fusion reaction, they reasoned, could vaporize a hunk of metal like that. Mere chemistry could not explain the heat, so that meant something else was going on.

  Their crazy hunch had paid off. Pons and Fleischmann felt they had made a momentous discovery. As they continued their research, they tried to keep it secret, letting only a few people into their confidence. But by the late 1980s, they were running out of money, so they started applying for outside funding. The first place Pons turned to was the Office of Naval Research; the ONR was already funding him to the tune of $300,000 per year for other work. But the ONR passed. Next up was the Department of Energy. Its Division of Advanced Energy Projects—a group that gives seed money to highly speculative research—was interested. But to award Pons and Fleischmann a grant, the department had to get the application peer reviewed; it had to send the chemists’ proposal to other scientists to get their opinions. (Scientific grant proposals, like scientific papers, tend to get accepted only after peer review.) One of the peers who reviewed Pons and Fleischmann’s proposal was a physicist at Brigham Young University, Steven Jones. As soon as Jones got a copy, all hell broke loose.

  Jones was a natural choice for a reviewer. He had long been interested in fusion, particularly fusion under unusual conditions. In the late 1970s, while working at a Department of Energy facility in Idaho, he became intrigued by a bizarre phenomenon discovered by Luis Alvarez—the Oppenheimer critic—in 1956. Alvarez was using a device known as a bubble chamber to study particle interactions; when a particle zipped through the chamber, it would leave a trail of bubbles behind, which allowed physicists to see how particles behaved. He discovered some curious tracks—they had gaps in them—that didn’t seem to make sense. He and his group visited Edward Teller’s home to talk about the phenomenon, and after an “interesting discussion” Alvarez and Teller realized that the mysterious tracks were the sign of nuclear fusion between a hydrogen and a deuterium.

  How could this be? Alvarez’s bubble chamber was extremely chilly—not far from absolute zero, in fact. How could the cold, slow-moving deuterium and hydrogen possibly have enough energy to overcome their mutual repulsion and fuse? The secret was a subatomic particle known as the muon. The muon is almost exactly like the electron, but it is some two hundred times heavier than its sibling. Like the el
ectron, it carries a negative charge. And like the electron, it can be captured by a proton to make a hydrogen atom. But this weird muon-hydrogen object is considerably different from ordinary hydrogen. It is more massive—and it is tinier. The muon’s extra mass means that it is held much closer to the nucleus than an electron is. Because the muon is held so close to the nucleus, these hydrogen atoms are considerably smaller than ordinary hydrogen atoms. Thus when a small muon-hydrogen atom collides with another atom, the two nuclei are much closer together than they would ordinarily be. The muon, wrote Alvarez, “in effect, confines the two nuclei in a small box.” Confined in that box, the two nuclei are much more likely to strike each other and fuse.53

  MUON-CATALYZED FUSION: Ordinary atoms have large electron clouds (left) that make it hard for the nuclei to get close enough together to fuse. Replace the electrons with muons (right) and the muon cloud is much smaller; nuclei get together much more easily and are able to fuse at relatively low temperatures.

  Muon-catalyzed fusion, as it came to be known, really was room-temperature fusion. If scientists could somehow replace the electrons in a jar full of hydrogen with muons, they would be able to get a fusion reaction without the need for immense heat and pressure; the muon hydrogens would fuse by virtue of their smaller size. Unfortunately, muons are hard to come by. To get them in large numbers, scientists need to build a particle accelerator. Accelerators consume lots of energy, and they are not very efficient.

  Even if scientists found an efficient way of producing muons, the muons they would create would last only a few microseconds before decaying into electrons and a handful of other particles. If in those moments the scientists then successfully shot one of those muons into a cloud of hydrogen, they might get lucky and induce two atoms to fuse into helium, but what then? The muon can get trapped in the helium atom, and then it is useless. It will quickly decay without helping any other atoms to fuse. If every available muon catalyzed only one atomic fusion, then there is no hope of producing energy; merely creating the muons and delivering them would consume more energy than was released by that single fusion. If, on the other hand, a muon can escape the clutches of the helium nucleus, then helps another fusion to occur, escapes, helps another fusion, and so forth, then muon-catalyzed fusion would not be hopeless after all. If every muon induces a few hundred fusions before decaying, then perhaps it would be possible to generate more energy than the amount used to create the particles in the first place. Muon-catalyzed fusion would achieve breakeven.

  When Alvarez first saw the phenomenon in deuterium, he was extremely excited. “We had a short but exhilarating experience when we thought we had solved all of the fuel problems of mankind,” he said in his Nobel Lecture a decade later. “While everyone else had been trying to solve the problem by heating hydrogen plasmas to millions of degrees, we had apparently stumbled on the solution, involving very low temperatures instead.” Unfortunately, as Alvarez’s team performed more detailed calculations, they concluded that the muons quickly got stuck in helium and decayed, and that muon-catalyzed fusion of deuterium would never lead to a practical energy source. Deuterium-tritium mixtures might fare a bit better, but the outlook was pretty grim.

  Jones was more sanguine about the possibility of using muons to generate energy than Alvarez had been, and he sought to prove that muon-catalyzed fusion could, indeed, solve the world’s energy problems. With grants from the Department of Energy—the same Division of Advanced Energy Projects that Pons and Fleischmann were soon to get involved with—Jones used an accelerator at Los Alamos to zap deuterium-tritium mixtures with muons. Theory predicted that as the deuterium-tritium mixture got denser, the muon would interact with more atoms before decaying—but that this effect would be very slight. Much to his surprise, when Jones increased the density of his deuterium-tritium mixtures, he discovered that the number of interactions skyrocketed into the hundreds. By 1986, he was claiming to see 150 fusions per muon and predicted that it would be possible to get even more.

  If it was true, muon-catalyzed fusion might really become an energy source. In a paper in the prestigious peer-reviewed journal Nature, Jones waxed enthusiastic about muon fusion, especially when using a mixture of deuterium and tritium as fuel: “each muon may catalyze hundreds of d-t fusion reactions, releasing a great deal of fusion energy,” he wrote, arguing that “muon-catalyzed fusion is an idea whose time has come—again.” (He also noted that muon-catalyzed fusion didn’t work at high temperatures as conventional fusion did: “The term ‘cold fusion’ is therefore quite appropriate for the process,” he wrote.)

  Jones trumpeted the potential of muon-catalyzed fusion in seminars, lectures, and papers, and cowrote a Scientific American article about it in 1987. “It is now conceivable that cold fusion may become an economically viable method of generating energy,” the article read, and it even included schematics for a “commercial cold-fusion reactor.”

  Unfortunately, Jones was wrong. His results were not only inconsistent with theory but also with what other groups were finding. A Swiss team, for example, performing similar experiments, was not seeing the same density effects that Jones was observing. Their muons got stuck in helium atoms fairly rapidly, as expected. Instead of seeing hundreds of fusions per muon, they were seeing tens. Muon-catalyzed fusion would never lead to breakeven at this rate. And as the Department of Energy’s money for muon-catalyzed fusion began to run out—the Division of Advanced Energy Projects had already spent more than $2 million—prospects for muon-catalyzed fusion began to dim. An outside review by JASON, a secretive group of scientists who advise the government on all matters scientific, put the last nail in the coffin: muon-catalyzed fusion wasn’t worth pursuing, at least as a path to energy. Muon-catalyzed fusion was dead. But cold fusion wasn’t.

  Around the time that Jones’s 1986 Nature paper came out, an astronomer and physicist, E. Paul Palmer, attended one of Jones’s muon-catalyzed-fusion seminars. The idea of fusion at low temperatures struck Palmer as the possible answer to a conundrum. Palmer was a rogue physicist; he had apparently come to the conclusion that much of what geophysicists believe about the Earth is “a bunch of baloney,” and was hard at work formulating alternative geological theories. The conventional wisdom that the Earth’s interior is warmed by the decay of heavy elements like uranium struck him as being wrong. And the fact that there is helium-3 in the Earth’s crust seemed to him to be evidence of fusion.54

  Most physicists would have dismissed Palmer as a crank, but Jones did not. After all, he himself had seen how fusion can happen at low temperatures; perhaps there was some other substance besides muons that could induce low-temperature fusion. Perhaps metals—nickel? platinum? palladium?—could trap hydrogen atoms and force them to fuse. It was cold fusion of another sort. Jones’s initial experiments didn’t turn up much, despite some halting attempts to capture gamma rays coming from fusion in metal samples. The concept of cold fusion remained on the back burner until the day that Jones received Pons and Fleischmann’s grant application in 1988.

  There are many different versions of precisely what happened after Jones read the proposal, but there is little doubt that it sparked a race that grew more frantic as each week passed. Pons and Fleischmann’s work had much in common with Jones’s. Both were hoping to trap deuterium in a hunk of metal—particularly palladium—and force it to fuse somehow. If money was to be made from cold fusion (and if Pons and Fleischmann were correct, cold fusion would be a moneymaker unlike almost any other invention), only the patent holders would see huge benefits. Only the people who discovered cold fusion would be able to patent the process. And only the people to go public with their work first would be hailed as the discoverers. All the money, glory, and power that might come from the discovery of cold fusion hinged upon being the first to go public. The first to cross the finish line would be hailed as the savior of mankind, as the discoverer of an eternal spring of unlimited energy. The second would become a mere footnote.

  Jones,
Pons, and Fleischmann had entered an ever-quickening race to run experiments, prove the existence of cold fusion, write a paper for a peer-reviewed journal, and publish it. By early 1989, the competitors had agreed to submit simultaneous papers to Nature, so they could all cross the finish line simultaneously. But in a climate of increasing mistrust and antagonism, Pons and Fleischmann jumped the gun. They submitted their paper to the Journal of Electroanalytical Chemistry on March 10, and within two weeks they were in front of the microphones, touting their achievement to the world—despite the improbability of what they had found. “Stan and I often talk of doing impossible experiments,” Fleischmann said in the official University of Utah press release about cold fusion. “We each have a good track record of getting them to work.”

  In truth, Pons and Fleischmann did not have the grounds for such hubris. Though they exuded confidence at the March 23 press conference, they already should have known that their data did not add up. They had several lines of evidence for the claim that they had achieved nuclear fusion in their tiny little beakers—but these lines contradicted one another.

  The strongest line of evidence, as far as the chemists were concerned, was heat. When Pons and Fleischmann measured the temperature of their apparatus, their electrochemical “cell,” they discovered that the palladium was warming it up ever so slightly. Of course, many things can warm up a cell—the electricity they were running through the cell, for example, was certainly contributing to the warming—but Pons and Fleischmann argued that the energy coming from the palladium was considerably more than what they added in the form of electricity. According to Pons, an inch-long and quarter-inch-thick palladium wire brought water to a boil within minutes, and for every watt of power the scientists put in, four watts came out. More energy out than in implies a reaction of some sort. Since the reaction kept going and going, reportedly for more than one hundred hours, the amount of energy coming from the cell was too large to be explained by a chemical reaction. It was like Marie Curie’s hunk of radium; mere chemical processes couldn’t seem to explain the heat coming from the cell. To Pons and Fleischmann, this was a smoking gun of a nuclear reaction: fusion.