Einstein’s work was not without promise, at first. He was attempting to unite the force of gravity—which he had successfully described in his general theory of relativity—with the force of electromagnetism, and the two forces are similar in many ways. The strength of both, for instance, is inversely proportional to the square of the distance between two bodies, and both have an infinite range. Einstein wasn’t alone in his conviction that he could solve the problem. In 1919 the German mathematician Theodor Kaluza and, later, the Swedish physicist Oskar Klein had suggested a different way to join the two forces. Just as Einstein had introduced a fourth dimension into his equations of general relativity to describe gravity, Kaluza and Klein suggested that a fifth dimension was needed to incorporate electromagnetism.
Einstein spent the last two decades of his life refining this idea. At the same time, he tried to iron out what he saw as problems in his general theory of relativity. In cases where gravity was extremely strong, his theories broke down. Moreover, they seemed to permit the formation of what we now call black holes—objects of such enormous density that their gravity traps even light. “Einstein didn’t like black holes,” Moffat says. “The real motivation for generalizing his gravity theory was to see if he could find, as he called them, ‘everywhere regular solutions’ that fit the equations.” Such solutions, Einstein hoped, would eliminate black holes entirely.
In 1939 the physicist J. Robert Oppenheimer used general relativity to show in detail how black holes could form from collapsing stars. Yet Einstein was undeterred. Throughout the 1940s, he continued his fruitless search for a revolutionary new theory, even as quantum mechanics advanced at a blinding pace. “He was in denial,” Moffat says. “Even Einstein went into denial, because he had invested so much time in this—years!” Near the end of his life, Einstein realized that he wouldn’t live to complete his work. “I have locked myself into quite hopeless scientific problems,” he wrote, “the more so since, as an elderly man, I have remained estranged from the society here.”
When Moffat first read Einstein’s later work in 1953, he didn’t dismiss it as many physicists did. But then Moffat was no physicist at the time. As an out-of-work 20-year-old in Copenhagen, he had become interested in cosmology while browsing through the library in his spare time. To his surprise, he found that he could easily absorb the advanced mathematics and physics in popular science books and magazines. He plowed through four years’ worth of college-level material in about a year, then moved on to professional physics journals. “I got hold of some of Einstein’s papers and decided that there was some weakness in what he was doing,” he says. “So I wrote two papers and sent them to him at Princeton. I never thought I’d hear anything from him.”
Moffat had identified a mistaken assumption in the mathematics Einstein was using to describe the electromagnetic force. Einstein conceded that Moffat had a point. They went on to exchange several letters over the next six months, inspiring Moffat to pursue a career in physics. Although he lacked formal training in the field, Moffat knew that Einstein’s letters might earn him an audience with other physicists. So he contacted Niels Bohr’s secretary at the University of Copenhagen and mentioned the letters. Bohr readily agreed to meet him. “Einstein was confiding his problems in physics with me,” Moffat says, “and Bohr wanted to know what he was saying.”
During the two-hour interview that followed, Bohr mumbled so quietly that Moffat had to strain to hear him. Bohr had hoped to hear of a change of heart on his rival’s part, but Moffat’s letters disappointed him: Einstein was still openly skeptical of quantum mechanics. “Finally, Bohr said that as far as he was concerned, Albert had become an alchemist,” Moffat remembers. In his search for a transcendent theory, Einstein had lost touch with the roll-up-your-sleeves world of experimentation and drifted off into the realm of metaphysics. “He thought Einstein was wasting his time,” Moffat says. “And he told me I was wasting my time with my interest in Einstein’s ideas.”
It didn’t end there. A local newspaper went on to publish a story about Moffat’s encounters with Einstein and Bohr, and that story prompted the British consulate in Copenhagen to contact the Department of Scientific and Industrial Research in London. The department brought Moffat to London and paid his way to the Institute for Advanced Studies in Dublin, for an interview with Erwin Schrödinger.
A polymath who spoke six languages, Schrödinger was most famous for the wave equation that now bears his name—an elegant mathematical description of one of the central mysteries of quantum theory—which shows that all particles can also behave like waves. When Moffat arrived for a two-day visit, Schrödinger was sick in bed with severe bronchitis. During their interview, the great physicist would peer at his young visitor through round, rimless spectacles. Moffat knew that he wouldn’t hesitate to dismiss him as an impostor and send him back to a life of obscurity in Denmark. Once again, however, things went smoothly until Moffat mentioned his interest in Einstein’s work.
“He got very angry,” Moffat remembers. “He started shouting at me from his bed. He said Einstein was a fool. I was quite overwhelmed.” What most enraged Schrödinger was that he, too, a decade earlier, had tried to develop a unified theory with an approach very similar to Einstein’s. He had become increasingly skeptical that a unified field theory was even possible. But Einstein, in any case, was headed in the wrong direction.
