sign in sign up
<<
Home , Einstein Wrote Back, John Moffat (physicist)

PAGE PROOF Date ______MW______AuCx____ Copy ____ JT____ DG____ SLP____ MP____

AGE 64 Einstein’s Grand Quest for a Unified Theory He failed, of course, but he didn’t exactly waste his time

stein was at the Institute for Advanced Study situation is the following. We are stand- in Princeton, New Jersey. Yet both men ing in front of a closed box which we can- were outsiders of a sort. In his later years, not open, and we try hard to discover about Einstein had become increasingly isolated what is and is not in it.” That closed box from the mainstream community, is the universe, of course, and no one had refusing to embrace the strange but pow- done more to pry off the lid than Einstein. erful theory of quantum mechanics—with Yet in the eyes of nearly all his colleagues its particles that are also waves and that he had contributed almost nothing of im- transform simply because they’re observed. portance to physics for almost 20 years. Nature, he argued, couldn’t be so perverse. Were they right? Did he squander his ge- So for nearly 30 years he had pursued what nius by chasing vainly after an ultimate the- most considered a quixotic goal: ory? That is the conventional view. But at the creation of a to de- least a few physicists now argue that Einstein scribe all the forces of nature. was far ahead of his time, raising questions URIED IN ’S MAIL ONE SPRING That was the occasion for Moffat’s let- that will challenge researchers for decades. day in 1953 lay a letter from an ordinary ter. He thought he could offer Einstein “It’s often said that Einstein wasted his time mortal, a 20-year-old high-school dropout some constructive criticism.“I wrote him later in life,”Moffat, who went on to become Bnamed . Two more disparate to say that I wasn’t happy about what he a theoretical , says.“This of course correspondents would be hard to imagine. was doing,”Moffat recalls. There was noth- is erroneous. Einstein never wasted his time.” Moffat was an impoverished artist and self- ing unusual about this. Plenty of people Einstein and his colleagues, taught physicist. Einstein was a mythic fig- sent letters to Einstein, not all of them ra- EINSTEIN’S SPLIT WITH MAINSTREAM PHYSICS Valentine Bargman and Peter ure—the world’s most famous scientist. tional. But in Moffat’s case something un- came at the very height of his career. In 1927, Bergman, discuss physics at Moffat was living with his British father expected happened: . when he was 48, the world’s leading physi- Princeton in 1940. What most bothered Einstein about quantum and Danish mother in Copenhagen. Ein- “Dear Mr. Moffat,”the reply began.“Our cists gathered at a conference in Brussels to mechanics wasn’t that God plays dice, but that our own observations influence how the dice roll. 1 BY TIM FOLGER Informantion here about the writer of the story very accomplished authere ot eh aejrkleha ktheklajrkleaj 2

C M Y K C M Y K 110000 AGE 64

debate an issue that remains contentious to and they suggested a simple thought ex- thought experiment was meaningless: If lem. In 1919 the German mathematician HEN MOFFAT FIRST READ EINSTEIN’S him: Einstein was still openly skeptical of this day: What does quantum mechanics periment to explain why: Imagine that a the second particle was never directly mea- Theodor Kaluza and, later, the Swedish papers in 1953, he didn’t dis- quantum mechanics. “Finally, Bohr said have to say about reality? Einstein had won particle decays into two smaller particles sured, it was pointless to talk about its prop- physicist Oskar Klein had suggested a unique W miss them as professional that as far as he was concerned, Albert had the Nobel Prize in physics for research that of equal mass and that these two daughter erties before or after the first particle was way to join the two forces. Just as Einstein physicists did. But then Moffat was no become an alchemist,”Moffat remembers. showed that light consists of particles—re- particles fly apart in opposite directions. In measured. But it wasn’t until 1982, when had introduced a fourth dimension into physicist at the time. As an out-of-work In his search for a transcendent theory, Ein- search that helped lay the groundwork for order to conserve momentum, both parti- the French physicist Alain Aspect con- his equations of to de- 20-year-old in Copenhagen, he had be- stein had lost touch with the gritty, roll-up- quantum mechanics. Yet he dismissed the cles have to have identical speeds. If you structed a working experiment based on scribe , Kaluza and Klein suggested come interested in while brows- your-sleeves world of experimentation. He new theory out of hand. At the conference, measure the velocity or position of one par- Einstein’s ideas, that Bohr’s argument was that a fifth dimension was needed to in- ing through the library in his spare time. was practicing metaphysics, not physics. he clashed with the great Danish physicist ticle, you will know the velocity or position vindicated. In 1935 Einstein was still con- corporate . To his surprise, he found that he could eas- “He thought Einstein was wasting his time,” , launching a feud that would last of the other—and you will know it with- vinced that he had refuted quantum me- Einstein spent the last two decades of ily absorb the advanced mathematics and Moffat says.“And he told me I was wasting until Einstein’s death in 1955. out disturbing the second particle in any chanics. And from then until his death 20 his life refining this idea. At the same time, physics in popular science books and mag- my time with my interest in Einstein’s ideas.” Bohr championed the strange new in- way. The second particle, in other words, years later, he devoted nearly all his efforts he tried to iron out what he saw as prob- azines. He plowed through four years’ It didn’t end there. A local newspaper sights emerging from quantum mechan- went on to publish a story about Moffat’s ics. He believed that any single particle—be encounters with Einstein and Bohr, and it an electron, proton, or photon—never that story prompted the British consulate occupies a definite position unless some- in Copenhagen to contact the Department one measures it. Until you observe a par- “I have locked myself into quite hopeless of Scientific and Industrial Research in Lon- ticle, Bohr argued, it makes no sense to don. The department brought Moffat to ask where it is: It has no concrete reality; scientific problems,”Einstein wrote near London and paid his way to the Institute it exists only as a probability. the end of his life.“I have remained of Advanced Study in Dublin, for an inter- Einstein scoffed at this. He believed, em- view with Erwin Schrödinger. A polymath phatically, in a universe that exists com- estranged from the society here.” who spoke six languages, Schrödinger was pletely independent of human observation. most famous for the wave equation that All the strange properties of quantum the- now bears his name—an elegant mathe- ory are proof that the theory is flawed, he matical description of one of the central said. A better, more fundamental theory lems in his general theory of relativity. In worth of college-level material in about a mysteries of quantum theory: that all par- will eliminate such absurdities. “Do you cases where gravity was extremely strong, year, then he moved on to professional ticles can also behave like waves. really believe that the moon is not there his theories broke down. Moreover, they physics journals. “I got hold of some of Schrödinger was sick in bed with severe unless we are looking at it?” he asked. seemed to permit the formation of what Einstein’s papers and decided that there bronchitis when Moffat arrived for a two- “He saw in a way more clearly than any- we now call black holes: objects of such was some weakness in what he was doing,” day visit. During their interview, the great one else what quantum mechanics was re- enormous density that their gravity traps he says. “So I wrote two papers and sent physicist would peer at his young visitor ally like,”the British physicist Julian Barbour even light.“Einstein didn’t like black holes,” them to him at Princeton. I never thought through round, rimless spectacles. Moffat explains.“And he said,‘I don’t like it,’”In the Moffat says.“The real motivation for gen- I’d hear anything from him.” knew that he wouldn’t hesitate to dismiss years following the conference in Brussels, eralizing his gravity theory was to see if he Moffat had identified a mistaken as- him as an impostor and send him back to a Einstein leveled one attack after another at could find, as he called them,‘everywhere sumption in the mathematics Einstein was life of obscurity in . Once again, Bohr and his followers. But for each attack regular solutions’ that fit the equations.” using to describe the electromagnetic force. however, things went smoothly until Mof- Bohr had a ready riposte. Then in 1935 Ein- Such solutions, Einstein hoped, would Einstein conceded that Moffat had a point. fat mentioned his interest in Einstein’s work. stein devised what he thought would be the eliminate black holes entirely. They went on to exchange several letters “He got very angry,”Moffat remembers.“He fatal blow. Together with two colleagues at In 1939 the physicist J. Robert Oppen- over the next six months, inspiring Moffat started shouting at me from his bed. He said Princeton, Nathan Rosen and Boris Podol- Einstein’s office at Princeton [ck]. “He was always interested in deep questions,” physicist Carlo Rovelli says, heimer used the theory of general relativ- to pursue a career in physics. Although he Einstein was a fool. I was quite overwhelmed.” sky, he found what appeared to be a serious “and a lot of physicists didn’t care about deep questions. They left the deep questions to Einstein.” ity to show in detail how black holes could lacked all formal training in the field, Mof- What most enraged Schrödinger was that inconsistency in one of the cornerstones of form. Yet Einstein was undeterred. Through- fat knew that Einstein’s letters might earn he, too, a decade earlier, had tried to develop quantum theory: the uncertainty principle. can be precisely measured at all times. to the search for a unified field theory. out the 1940s, he continued his fruitless him an audience with other physicists. So a unified theory with an approach very sim- Formulated in 1927 by the German Einstein and his collaborators published His work was not without promise at search for a revolutionary new theory, even he contacted Niels Bohr’s secretary at the ilar to Einstein’s. But he had abandoned the physicist Werner Heisenberg, the uncer- their thought experiment in 1935, with first. He was attempting to unite the force as quantum mechanics advanced at a blind- University of Copenhagen and mentioned effort when it became apparent to him that tainty principle puts strict limits on how the title,“Can Quantum-Mechanical De- of gravity—which he had successfully de- ing pace. “He was in denial,” Moffat says. the letters. Bohr readily agreed to meet him. he was getting nowhere. He couldn’t toler- accurately one can measure the position, scription of Physical Reality Be Consid- scribed in his general theory of relativity— “Even Einstein went into denial, because “Einstein was confiding his problems in ate Einstein’s refusal to do the same. velocity, energy, and other properties of a ered Complete?” The paper was in many with the force of electromagnetism, and he had invested so much time in this— physics with me,” Moffat says, “and Bohr particle. The very act of observing a par- ways Einstein’s swan song: Nothing he the two forces are similar in many ways. years!” Near the end of his life, Einstein re- wanted to know what he was saying.” MOFFAT WENT ON TO BE ACCEPTED INTO THE ticle also disturbs it, Heisenberg argued. wrote for the rest of his life would match The strength of both, for instance, is in- alized that he wouldn’t live to complete his During the two-hour interview that fol- graduate program in physics at Cambridge If a physicist measures a particle’s posi- its impact. If he was right, then quantum versely proportional to the square of the work.“I have locked myself into quite hope- lowed, Bohr mumbled so inaudibly that University, thanks in part to Schrödinger’s tion, for example, he will also lose infor- mechanics was inherently flawed. distance between two bodies, and both have less scientific problems,”he wrote,“the more Moffat had to strain to hear him. Bohr had strong recommendation. In 1958, he be- mation about its velocity in the process. Quantum physics, of course, eventually an infinite range. Einstein wasn’t alone in so since, as an elderly man, I have remained hoped to hear of a change of heart on his came the first student in the 800-year his- 3 Einstein, Podolsky, and Rosen disagreed, carried the day. Bohr argued that Einstein’s his conviction that he could solve the prob- estranged from the society here.” rival’s part, but Moffat’s letters disappointed tory of the school to earn his Ph.D. without 4

C M Y K C M Y K AGE 64

first completing an undergraduate degree. Two thousand light-years from Earth, NE DAY, OVER LUNCH AT A BISTRO NEAR Moffat now works at the Perimeter Insti- for instance, two young blue stars in a sys- Moffat’s office, I asked him if we tute near Toronto, Ontario—an icono- tem called DI Herculis whirl about each O will ever see the likes of Einstein clastic veteran among some of the world’s other every 10 1/2 days. Their paths shift again. He shook his head. “If you go and best and brashest young physicists. If he slightly from one orbit to the next—a phe- visit Chartres cathedral in France, you’ll was first drawn to Einstein by his mistakes, nomenon known as precession—but when realize that it took 150 years to build, and he now believes the old man may have astronomers use general relativity to pre- we don’t know the names of the artisans been on the right path after all. He just dict this shift, their answers are off by a who built it. They’re anonymous. Maybe started down it a few decades too soon. factor of four. Most astronomers believe physics is going to become like this. We In the 1930s, when Einstein began his that a third star, unobserved as yet, is dis- may one day have a great edifice for West- work on the unified field theory, physicists turbing the orbit. But Moffat doesn’t think ern civilization—not a theory of every- believed that there were only two univer- so. In his modified version of Einstein’s thing, but still a great edifice.” To claim sal forces that the theory would have to later theory, the gravitational pull between there is an ultimate theory is “pure hubris,” unite: gravity and electromagnetism. They Moffat said. “There’s always something have since learned that there are two other new on the horizon, and then everything fundamental forces as well: a strong force starts all over again.” that binds atomic nuclei and a weak force Einstein was the first victim of his own that governs radioactive decay. “Einstein ‘Schrödinger got success, Giovanni Amelino-Camelia, a defined what later became a fundamental very angry. He physicist at the University of Rome, likes problem in physics,” says Carlo Rovelli, a to tell his students. He gave rise to the ro- theoretical physicist at the University of started shouting at mantic notion that a genius who follows the Mediterranean in Marseille, France. his intuition can create a perfect theory “But he was missing an ingredient.” me from his bed. that explains all the data. And then he fell These days Einstein’s once-lonely quest He said Einstein prey to that notion himself.“It’s a success engages thousands of physicists around which has really been a mixed blessing for the world, most of them string theorists. was a fool.’ theoretical physics,”Amelino-Camelia says. While their work is grounded in quantum “If we didn’t have that one example we mechanics, it relies heavily on some of the would have no examples. And that would same components that Einstein used. Ac- teach people how science is really done.” cording to string theory, the fundamental the two stars is weakened just enough to And yet, once upon a time, Einstein did constituents of the physical world are not slow the stars’ orbits down a bit. By his revolutionize physics. And he did so in large pointlike particles, but infinitesimal, one- new calculations, the precession agrees ex- part thanks to his stubborn, independent, dimensional loops, or strings. All the par- actly with observations. audacious spirit. The general theory of rel- ticles and forces in the universe arise from There’s no small historical irony to all ativity was developed in defiance of cen- these strings vibrating at different fre- this. One of the first rigorous tests of gen- turies of physics. It consumed Einstein for quencies. But here’s the catch, and no doubt eral relativity was an observation of the pre- 11 years—from 1905 to 1916—and in the it would have made Einstein smile: The cession of Mercury’s orbit around the sun. end was proved triumphantly correct. It’s strings need 11 dimensions in which to Before Einstein, most astronomers assumed, no wonder the memory of that achieve- vibrate. And these extra dimensions are as with DI Herculis, that a third body would ment sustained him in later years. In 1953, described by essentially the same mathe- make the orbit conform to Newton’s equa- when the letter from John Moffat found matics that Einstein used in his own five- tions. Some even claimed to have observed its way to Princeton, Einstein was still do- dimensional unified field theory. the mystery planet and have named it Vul- ing what he had always done—asking big Moffat is not so sure that string theory can. Einstein’s general theory of relativity questions and looking for the answers. is an improvement on Einstein’s ideas. But made the third planet unnecessary. At lunch that day in Ontario, Moffat for much of the past decade he has returned Could the third star in DI Herculis turn said that he had one more letter from Ein- to the theory that Einstein was working on out to be as illusory as Vulcan? If so, it would stein to show me. He rummaged through when he died—the same one that prompted be very big news indeed. Moffat claims that a folder, pulled out a copy, and pointed to Moffat’s fateful letter. Moffat argues that his theory would eliminate the need for the date: May 25, 1953. Then he read the the mathematics Einstein hoped would de- and dark energy—two phe- words that have guided him for more than scribe electromagnetism in his unified field nomena, as yet undetected, that physicists half a century: “Every individual . . . has Einstein and Niels Bohr fought theory gives rise, instead, to a slight repul- have invoked to account for the motions to retain his way of thinking if he does not for nearly half a century over sive force that reduces the strength of grav- of galaxies and expansion of the universe. want to get lost in the maze of possibili- quantum mechanics. “An inner ity. And that force might help solve certain It’s a long shot, Moffat says, but Einstein’s ties. However, nobody is sure of having voice,” Einstein wrote, “tells me that it is not yet the real thing.” 5 long-standing puzzles in astronomy. last theory may have some life in it yet. taken the right road, me the least.” 6

C M Y K C M Y K