ONE DAY IN JUNE 1955, as I was walking through Trinity Great Court, a senior fellow of the college waved to me across the court and approached me, walking on the sacred college lawn, which, as a fellow, he was permitted to do, and as a lowly student I was not. “Moffat, I’ve been asked to tell you that we would like you to attend the fifty-year commemoration of Einstein’s discovery of special relativity, in Bern, Switzerland. Mr. Hoyle has been invited to attend the commemoration to represent Cambridge, but he is not able to be there.”
I knew, of course, that Hoyle was away in the States doing research. Also, Hermann Bondi, a fellow at Trinity College and a collaborator of Hoyle’s, had a few months earlier been appointed professor of mathematics at King’s College London, and therefore would probably represent King’s College rather than Cambridge at the conference. “I’m only a research student,” I answered. “Wouldn’t it be more appropriate for a senior person to attend?”
The fellow assumed a stern look and said, “But you’re the only person doing work on relativity and gravitation at present, and I’ve heard you’re publishing papers on gravitation in our Cambridge Proceedings. Is that right?”
“Yes, that is correct.”
“Our college bursar will provide you with 30 pounds to cover your travel expenses.”
This amount would barely cover my travel expenses, and anything additional would have to come out of my meagre grant money. However, it seemed inappropriate for me to suggest that this would not be enough expense money, or that I wouldn’t like to attend the ceremonies in Bern. Besides, I decided that it might be fun, and I would meet some famous physicists. I agreed to go to Bern and represent Cambridge. I only wished that I could have met Einstein himself there, but he had died only two months before.
In fact, I had written a final letter to Einstein on April 15, 1955. Since he died on April 18, it would not have reached him in time. “Dear Professor Einstein,” I had written. “Since I received your last letter two years ago in Copenhagen, I have been fortunate to become established at Trinity College, Cambridge, as a research student. I send you enclosed some of myrecent work on generalizing gravitation theory.” The paper was my first published generalization of Einstein’s gravitation theory, based on a complex symmetric metric tensor and complex Riemannian geometry.
I had been eager to hear what Einstein would make of this new, original modification of his gravity theory. Modifying Einstein’s gravity theory as he and I were attempting was not a popular endeavour at the time, and consequently I did not have other people I could discuss this subject with, including my supervisor. When I heard of Einstein’s death in the news, I felt very saddened, knowing that the world had lost one of the greatest physicists of all time, and I had also lost the personal connection with this great man who had been instrumental in my entering academic life and pursuing my goal to become a physicist.
The following week, I took a train from London, crossed the English Channel by boat and caught a connecting train in Paris to Bern. This was the first time I had travelled in Europe in so grand a style, and I was enjoying the new experience. I arrived in Bern a couple of days before the beginning of the conference, to acclimatize myself to the city. I went to see the famous Zytglogge, the clock tower in the heart of the old town. It was a bright, sunny day, and the historic Swiss buildings with their intricate architectural details impressed me.
As I stood in the clock-tower square, a red sports car zoomed in, and someone who looked like a clone of the Hollywood film star Cary Grant got out, flashing a grin. He asked, in a strong American accent, “Are you a physicist attending the meeting?”
“Yes, I am,” I answered. “How did you know I’m a physicist?”
“Well, there are ways of figuring this out,” he said, laughing. He shook my hand. “I’m Stanley Deser,” he said. “I’m on sabbatical leave in Europe at the moment, and dropped in to attend this meeting. I guess it should be interesting. Where are you from?” I explained that I was representing Cambridge.
Stanley flashed his smile at me again and said, “We’ll see each other again at the meeting in a couple of days. Hope you have a good time in Bern.” He hopped into his red sports car and zoomed off.
I had heard of Stanley Deser in connection with his work on relativity theory. He went on to do seminal work in gravitation theory at Brandeis University, in Massachusetts. With collaborators, he developed a fundamental way of solving Einstein’s gravitational equations.
The next day, during another perambulation through Bern, I ran into Bill Bonnor, who had been one of the professors that Greenall, at the Department of Scientific and Industrial Research, in London, had sent me to visit a year before. Bonnor was walking towards me on a charming, narrow street, accompanied by Geoffrey Stephenson, a mathematical physicist at Imperial College London. Bonnor smiled amiably at me and said, “Well, I understand that you are now a student at Trinity College. And here you are at this meeting. How did that come about?”
I told him about standing in for Fred Hoyle. “At the moment I am the only one publishing gravitational research at Cambridge,” I added.
Stephenson said, “I gather Felix Pirani is here, but I hear that he is going to King’s College in London, so I guess officially you’re the one they chose to represent Cambridge.”
The evening before the beginning of the conference, there was a reception at the University of Bern. The chief organizer of the conference was Professor André Mercier, a senior professor in the Department of Physics at Bern. The number of delegates at the meeting was small, compared to attendance at the large conferences that now take place in relativity and gravitation, which can number in the several hundreds. Among the famous physicists I shook hands with that evening was Wolfgang Pauli from Zurich, a short, stocky man with a big head and a rosy complexion. Pauli was one of the founders of quantum mechanics and went on to make important contributions to quantum field theory.
I also met Professor Satyendra Nath Bose, the Indian physicist famous for developing “Bose statistics” for what were later called “bosons,” which are particles with integer quantum spin such as the photon.* Later, in quantum physics, bosons became understood as the carriers of forces in subatomic physics. The important feature Bose discovered in his statistics is that the photons (bosons) are identical particles, whereas physicists had assumed that there were different kinds of photons. The Bose statistics were later called “Bose-Einstein statistics” because Einstein promoted Bose and made an important contribution to the subject. Bose looked dashing in his black beret and dark suit that evening.
I also shook hands with the celebrated German mathematical physicist Hermann Weyl, who was famous for his contributions to quantum mechanics and was the inventor of gauge theory, which would play a fundamental role in modern quantum field theory. I had read his book, Space, Time, Matter, which was one of the first books describing Einstein’s general relativity. He seemed like an amiable, kind man, and he was interested in discussing my research. While we were talking, the American physicist Robert Oppen-heimer strolled over, a drink in his hand, and Weyl introduced us. I was struck by Oppenheimer’s intense, light blue eyes and his handsome, aquiline face. I later observed that he always wore a three-piece grey suit with a shirt and tie, and looked more like a wealthy banker than a physicist, although in those days, in contrast to today, well-known physicists were usually attired in formal suits rather than T-shirts and jeans. As I stood hobnobbing with these famous physicists, it dawned on me that I was the youngest participant at the conference—just a second-year research student, only twenty-two years old.
We were gathered at this meeting to commemorate Einstein’s revolutionary paper on special relativity of 1905, “On the Electrodynamics ofMoving Bodies,” which changed our understanding of space and time forever in physics. In addition, there would be lectures on the developments of Einstein’s general relativity. There were also lectures on Einstein’s attempts to unify gravity and electromagnetism by, for example, Bruria Kaufman, an Israeli physicist who had been Einstein’s chief assistant in his later years at the Institute for Advanced Study at Princeton. She had devoted much of her research to investigating Einstein’s nonsymmetric field theory generalization of general relativity.
There was a session, too, on the significance of the gravitational waves prediction in Einstein’s gravity theory. At the time, there was much controversy about whether gravitational waves existed or not. Indeed, in 1936, Einstein and his assistant Nathan Rosen had published a paper on the properties of cylindrical gravitational wave solutions of Einstein’s field equations. The title of the original version of the paper was, “Do Gravitational Waves Exist?” This version was rejected by Physical Review. The anonymous referee of the paper was eventually revealed to be a young Caltech assistant professor, Howard Percy Robertson. This was the first paper by Einstein that was sent to an anonymous peer reviewer, and it was the first paper that Einstein had had rejected. In fact, it is not clear whether Robertson actually rejected the paper, or whether Einstein jumped to conclusions, being unfamiliar with the peer review system. Einstein probably resented the anonymous reviewer proposing modifications to the paper and claiming that there were errors in it. He reacted by treating the reviewer’s criticisms as an outright rejection of the paper.
Years later, I met Nathan Rosen, Einstein’s collaborator on that paper, at a bus stop in Padova, Italy, while attending a conference on general relativity. We fell into conversation and I asked him about this paper. Rosen told me that Einstein had been angry at the rejection. Rosen had been present in Einstein’s office that particular morning when his secretary brought in the mail with the letter from Physical Review.Upon reading the letter, Rosen said, Einstein leapt out of his chair and threw the envelope with the letter and the manuscript into his trash can, which he then kicked loudly around his office. He promptly wrote to the editor of Physical Review vowing never to submit a paper to the journal again. In the letter, he criticized the editor for not warning him upon submitting the paper that it would be subjected to anonymous refereeing. Fortunately, Rosen told me, he managed to retrieve the manuscript from the trash can, unbeknownst to Einstein. He revised it in accordance with the referee’s criticisms, and submitted it to the Proceedings of the Franklin Institute in Philadelphia, a journal that published manuscripts on entomology and various other specialized topics, not necessarily related to physics. They, of course, were delighted to receive a paper from Albert Einstein, one of the most famous physicists in the world, and they published it without peer review.
Apart from one letter published in the Physical Review, answering criticisms put forth by a chemist-physicist on Einstein’s non-symmetric unified field theory, Einstein was true to his word to the editor of the journal. The paper with Rosen on gravitational waves was probably the only genuine encounter Einstein had with anonymous peer review. In the early twentieth century, it was not common for German physics journals to send out papers for anonymous review, as is the case today. Normally, the editor of the journal would make the decisions as to whether papers would be published or not. As Einstein’s fame grew, his papers were almost automatically accepted for publication. Significantly, his famous five papers from 1905, as an unknown Swiss patent official, were accepted by the editor of the prestigious German physics journal Annalen der Physik without any peer review.*
After Einstein relocated to Princeton in 1933, he began to publish in American journals in English. The Physical Review had taken on the mantle of the leading journal in physics in the United States. Its editor at the time was John Tate. Einstein published two papers in the Physical Review before the trash can incident. The first was the famous 1935 paper by Einstein, Boris Podolsky and Nathan Rosen on what came to be known as the Einstein-Podolsky-Rosen (EPR) Paradox, which became one of the most cited papers in modern physics: “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?” This paradox was one of Einstein’s thought experiments that he promoted to criticize quantum mechanics and was part of the celebrated Bohr-Einstein debate that took place over several years in the 1930s and 1940s. Einstein, Podolsky and Rosen claimed that quantum mechanics was an incomplete description of nature. In fact, the physical interpretation of quantum mechanics remains a controversial issue today.
The second and last paper Einstein published in Physical Review was later in 1935, and also in collaboration with Rosen. The subject of “The Particle Problem in the General Theory of Relativity” was the Einstein-Rosen Bridge, known today as the “wormhole” solution of general relativity. Beloved of science-fiction writers, the wormhole was Einstein’s attempt to remove the problem of unphysical singularities in his gravitation theory. The wormhole is a mathematical portal in spacetime, allowing a space traveller to move more or less instantaneously through the universe and come out in a distant part of it, or into another universe.
One wonders whether Einstein could ever have succeeded in publishing many of his iconoclastic papers had he been subjected to the draconian type of peer review that prevails in the physics establishment of today.
Einstein’s problematic paper “Do Gravitational Waves Exist?” proved to be a major topic at the Bern Einstein Fest. It was compelling to think that gravitational waves, like electromagnetic waves, existed. Yet, in 1936, Einstein wrote to his colleague Max Born, “Together with a young collaborator [Rosen], I arrived at the interesting result that gravitational waves do not exist, though they had been assumed a certainty to the first approximation. This shows that the non-linear general relativistic field equations can tell us more . . .” In his paper with Rosen on gravitational waves, certain mathematical mistakes were made, and Robertson criticized these mistakes. In the published paper, the mistakes were corrected, and it was not stated categorically that gravitational waves did not exist. Indeed, at the time, Einstein vacillated between accepting the existence of gravitational waves and not accepting them.
Another assistant of Einstein’s, Leopold Infeld, who did not believe that gravitational waves were a physical prediction of Einstein’s equations, and were not realized in nature, gave a talk at the Bern conference.* Vladimir Fock, who was famous for his work on quantum field theory, having invented what is called the “Fock space,” also talked at the Bern conference. In contrast to Infeld, he fervently believed in the existence of gravitational waves.
Infeld and Fock gave talks one after the other at the meeting. Fock, a large, stocky Russian who kept adjusting his hearing aids since he was completely deaf without them, gave the first talk, presenting his reasons for believing in the gravitational wave solutions in Einstein’s theory. Infeld stood off to one side near the podium as Fock spoke. He was also a large man, a Polish physicist from the University of Warsaw. He was already beginning to bristle with indignation over Fock’s talk. When Fock finished speaking, Infeld went to the podium. When he started speaking, presenting his reasons for not believing in the existence of gravitational waves, Fock ostentatiously removed his hearing aids, raising laughter in the auditorium. Even Hermann Weyl, the chair of the session, smiled with amusement.
One of the presentations at the gravitational waves session was given by Hermann Bondi, who, in collaboration with his group at King’s College London, reported on new attempts to develop a more rigorous foundation for understanding the role of gravitational waves in Einstein’s non-linear gravitation theory.
At another session, chaired by Robert Oppenheimer, a young professor from an American university presented his recent work on relativity theory. Oppenheimer suddenly displayed an aggressive aspect of his personality. He interrupted the speaker and criticized him scathingly in a loud voice. The younger physicist went red in the face and seemed to have the wind blown out of his sails, and continued his talk rather lamely.
One afternoon after a session, Professor Mercier announced that we were all to proceed to the university’s Department of Zoology for a reception. We assembled in a large hall there, where tables had been set up with food and drinks, which some of the delegates, including Pauli and Bose, appeared to imbibe too heartily. After a couple of hours, the noise level in the hall increased significantly, and Pauli’s raucous laughter could be heard all over the room. I knew there was going to be another session starting up after the reception, and I wondered how the organizers could possibly think of having another session after all this alcohol had been drunk.
We all streamed back to the physics auditorium, and some of the older delegates like Pauli were visibly intoxicated. The Greek relativist Achilles Papapetrou gave the first talk in the session, describing his work on the motion of bodies in Einstein’s general relativity, and I listened attentively because this was a subject that I had begun working on at Cambridge and that would be part of my Ph. D. thesis. Pauli sat in the second row, nodding his head in a nervous tic.
When Papapetrou finished speaking, he descended from the podium and made the mistake of standing near Pauli. Someone asked Papapetrou a question, and he answered it by quoting Pauli on some technical matter having to do with the motion of bodies. Papapetrou was a tall man with a long neck and an Adam’s apple that thrust up and down as he spoke. Pauli looked up at Papapetrou and shouted at him, “Papapetrou, you are a Papageno!” in an insulting allusion to the character in Mozart’s Magic Flute. “If you have to quote me, Papageno, do it correctly or not at all! I refuse to have such nonsense attributed to me!” Papapetrou’s face reddened; he looked mortified. This was the first time I witnessed the famous Pauli publicly humiliating another physicist, his tongue no doubt sharpened by alcohol.
One day, the conference organizers took the delegates on a trip to Lake Brienz in the Bernese Mountains. As we sailed around the lake, I had the opportunity to stand next to Infeld and Fock, who continued to attack one another on the issue of gravitational waves. This time Fock did not remove his hearing aids.
We were let off at a small port on the lake, and Bonnor, Stephenson and I took a walk and viewed the magnificent mountains above us and the beautiful deep blue lake shimmering in the sun beneath us. Sure enough, as we walked back down into the village where the boat was docked, we heard Pauli laughing and shouting loudly from inside an inn, as he led another drinking session. Young and innocent as I was then, I was taken aback by the drunken, argumentative behaviour of some of the older delegates.
I don’t know whether those older delegates thought much about Einstein during that week in Bern—perhaps they were too jaded at that point in their lives—but I certainly experienced feelings of sadness and regret that Einstein had died just two months before this meeting, while my final letter to him was on its way. I walked by the building where his apartment had been located, at 49 Kram-gasse, where he had lived with his first wife, Mileva, and their infant son, Hans Albert. I walked over the Kirchenfeld Bridge that he had crossed every day to go to the patent office, where he worked as a second-class civil servant.
I wondered whether before he died, Einstein had received an invitation to this important Einstein Fest celebrating the fiftieth anniversary of his discovery of relativity, and whether he had considered attending. Einstein had never returned to Europe after fleeing Nazi Germany and taking up his position at the Institute for Advanced Study in Princeton in 1933, so perhaps he would have declined this invitation as he had so many others. I felt that it was a pity for me, personally, that he had not been present during that week in Bern, because I would have been thrilled to meet him in person, and complete our cycle of correspondence with a personal conversation about physics.
*Like spinning tops, elementary particles carry a quantity known as angular momentum or spin. Unlike spinning tops, the angular momentum of elementary particles comes in discrete quantities. Elementary particles fall into two groups, with spin represented either by integers 0,1,2, or half-integers such as 1/2 or 3/2. The integer spin particles such as the photon are called bosons (named after Bose) and the half-integer particles such as the electron and proton are called fermions (named after the Italian physicist Enrico Fermi).Wolfgang Pauli worked out the properties of spin in 1927. He introduced the exclusion principle, which prevents two electrons with the same spin from occupying the same quantum state in an atom, and which provides a quantum mechanical explanation of the periodic table of elements.
*In addition to “On the Electrodynamics ofMoving Bodies,” which introduced special relativity, the other papers Einstein published in his “miraculous year” of 1905 were “Does the Inertia of a Body Depend on Its Energy Content?,” which discussed the idea of the equivalence of mass and energy and contained the famous equation E=mc2;“On a Heuristic Point ofView Concerning the Production and Transformation of Light,” which asserted that light occurs not only in waves but in particles and led to the development of quantum physics; “On the Movement of Small Particles Suspended in Stationary Liquids Required by the Molecular-Kinetic Theory of Heat,” on Brownian motion; and “A New Determination of Molecular Dimensions,” based on Einstein’s Ph. D. dissertation, which calculated Avogadro’s number and the size of molecules.
*I would write to Leopold Infeld two years later, asking for information about the mistake I had found in his 1949 paper with Einstein.