FEBRUARY 4, 1955
I came home last night from a strenuous week of conferences. My Indian friend Abdus Salam (who is now fixed in Cambridge) flew over for the meetings. Dick Feynman was there from Pasadena. As far as we can discover, Salam and Feynman and I are the only three who have invitations to Moscow. We are all three seriously trying to go. It seems I am the furthest along so far. I had a prompt reply from the British consul in New York saying he has enquired from London, and HM Government will give me all the usual diplomatic protection and has no objection to my making the trip. I also wrote to the American immigration authority demanding a written statement that they approve this journey and will let me back into the country afterwards. If I do not get their approval in writing, I shall not go. The situations of Feynman and Salam are different. Feynman is a U.S. citizen by birth and so could have no difficulty reentering the country. But he has worked at Los Alamos, and so they may not feel inclined to give him a U.S. passport valid for the USSR. Salam has a more complicated problem because he is not resident here but wants to visit here from time to time. He wants the American visa authority to approve his going to Moscow so that they will not hold it against him at some hypothetical future time when he may apply for a visa. I think that of the three of us, I am in the most favorable position, and it may well be that I am the only one who succeeds in going.
All through the years of war and political hostility, some personal contact between Soviet and Western scientists was maintained. Some senior scientists from the USSR were permitted to travel to the West on official business, and a smaller number of Western scientists were admitted to the USSR. We knew that there were many excellent physicists in Russia who were not allowed to travel, for example Pyotr Kapitsa, Igor Tamm, Lev Landau, Andrey Kolmogorov, Vladimir Veksler, and Yakov Zeldovich. We could read many of their theoretical papers in the open literature, but they published little about experiments. The invitation in 1955 offered me a chance to make friends with the Russian theorists and perhaps to find out what the experimenters were doing.
MARCH 1, 1955
I discovered some interesting things in the latest issue of the Russian physics journal. There is a string of seven papers describing experiments they have done with a big proton accelerator of 660 million volts. They have had the machine operating for three years, but until now there has never been a word published about any experimental work in nuclear physics. Of course, it was idiotic to keep such a thing secret. (American machines of this kind have never been secret.) It shows some glimmerings of common sense that they now make it public. My trip to Moscow may be more profitable if they are free to talk about their experimental work. What they have done with the machine is competent and careful work, but nothing particularly new or exciting.
MARCH 18, 1955
I am sorry to say that I will not come and see you in April, as the Moscow scheme failed. The crisis came on Monday, when I went to Washington to the central office of the Immigration Service. It was a beautiful day, and Verena drove me to the station full of high hopes at six-thirty a.m. I got to the office about eleven and was received in a friendly and informal way by the big boss. He told me what is written in this letter to Salam which I enclose. After this interview I walked around Washington for some hours, sweating out a decision. I was still free to go to Russia, and I would stand a very good chance of getting back. If I would go and get back safely, it would be a victory for the international brotherhood of science, showing the world that a courageous individual can place his trust in the good faith of Russian scientists and not be disappointed. On the other hand, if I would go and get into trouble, having my name attached to a political statement condemning the American Imperialists, making me appear to be a Communist Dupe, I would show the world exactly the opposite. In that case I would show the world that an individual placing his trust in the good faith of Russian scientists is an idiot. It all depended on whether I myself trust the Russians not to turn the conference into a political junket.
I decided finally, I trust the Russian scientists, who are genuinely interested in discussing the kind of work I have been doing. But I do not believe these scientists would have any control over the situation, if the local political people decided to interfere. So I was forced to the conclusion, I do not trust these people to keep it nonpolitical; and if I do not trust them myself, it is crazy to risk my job for the principle that one ought to trust them. After I made up my mind about this, I walked over to the National Gallery and relaxed my spirit with Rembrandt and Cézanne. Perhaps if Washington had not been so beautiful that day, I would have decided differently. There was such a peace over the city, with its wide grass spaces where you can walk for miles without meeting anybody, its clean white buildings and brilliant blue sky. It would be very hard to say good-bye to all this.
[ATTACHMENT] MARCH 15, 1955
Dear Salam,
I am sorry to say I had to give up the Moscow conference. I feel very bad about this, but I decided not to risk it. Yesterday I went to the head office of the Immigration Service in Washington. They were intelligent people and on the whole cooperative. They said: (1) They are specifically forbidden by law to give me any guarantee that I may reenter the U.S. (2) If I go to the Moscow conference and get involved in no political manoeuvres, this would not be a reason for them to exclude me from the U.S. (3) If I get involved in any political activities, if my name is used by the Russians for any propaganda and gets into the newspapers, if the conference starts to pass resolutions condemning the American imperialists, or anything of this kind, then I am classified as a “Communist Dupe.” (4) The Immigration Service made its own enquiries to find out whether this conference was a bona fide scientific affair or not and was unable to obtain any information. If I rely on my own judgment in believing that the conference is nonpolitical, the risk is entirely my own. If it turns out that I have been duped, I am not to expect any sympathy from the Immigration Service. I myself believe strongly that this is a genuine nonpolitical conference. But the risk is there, and for me the penalty is too heavy to take a chance on it. Best of luck!
Yours ever,
Freeman.
APRIL 14, 1955
I knew you would be opposed to my going to Moscow, and I was glad you had the tact to say nothing about it until the decision was made. I understand very well your point of view. However, I know now that there was in fact no political propaganda attached to it. It would have been perfectly all right if I had gone, and I am now sorry I was not brave enough to take a chance on it. The story came out last Wednesday, when the Moscow radio broadcast a statement that the conference had taken place. The statement was entirely factual and nonpolitical in content, and it was clear that the conference itself had been nonpolitical. The physicist Igor Tamm, whose name I know well, made the broadcast, which was sent out on the day the conference ended. There was a list of the people who were there, and he said, “Unfortunately the Americans Feynman and Dyson, who at first accepted our invitations, were prevented by their government from attending.” That was all he said about us, and I think it is not objectionable.
When this Moscow radio broadcast was received, the New York Times Russian expert called me up and read me the statement, and I told him my side of the story. The result appeared on page one of the Times on Thursday. I was glad to see this account also kept strictly to the facts. It is easy to be wise after the event. If I had to make the same decision again without knowing more than I did at the time, I should again say no.
My parents were against my going to Moscow for the same reason that I decided against it. They were afraid that I might be walking into a political trap.
Of the people who were there, two are personal friends of mine. One is Gunnar Källén, a young Swede who was here at the institute last year. Of course Sweden made him no trouble about such a visit. I am very glad he went, because I shall see him before long and hear about it in detail. He will have picked up whatever there was to be picked up. The other friend of
mine is Ning Hu who came from Peking. He was a research associate at Cornell in my time, and we used to talk about all kinds of things, especially about China. After the Communist government was established, he decided to go back home. He was aware of the difficulty of living in a Communist society and expected to have plenty of troubles. He had his roots so strongly in China that he had to go back ultimately, and he thought the sooner he went, the easier it would be. After he went back, I heard nothing about him until now. It is good to know that he has established himself and is in good standing. If this were not so, he would not be sent to Moscow.
The purpose of the 1955 Moscow conference was to open up communication between the USSR physicists and the rest of the world. The conference was only partially successful since few visitors came. In 1956 there was a highly successful conference with a much larger number of visitors. Since that time, the Russian physicists have never been isolated from the world community.
I was invited by Charles Kittel to spend a second summer in Berkeley. We rented the same house that we had occupied in 1953, and I worked again happily with Kip and Kittel on problems of solid-state physics. Out of this work grew a theory of spin waves. Spin waves are waves of magnetization running through the atoms of a solid material. I calculated spin waves by the same mathematical method that I had used for quantum electrodynamics five years earlier. This was the same strategy that failed when I tried to use it to calculate nuclear processes at Cornell. To my delight, the strategy succeeded magnificently when I applied it to spin waves.
OCTOBER 21, 1955
I have been working at high pressure from the day we got home. A lot of accumulated jobs connected with the institute and its affairs. To bring in a few extra dollars, I am translating Russian papers for the American Physical Society. Yesterday I did one written by our friend Pontecorvo. He is certainly not the great genius that the newspapers picture him to be. What he does is solid and sound and useful and a bit dull.
Bruno Pontecorvo was a brilliant Italian experimenter who worked as a young student with Fermi in Rome and joined the Communist Party in Paris. As an Italian Jew, he had to escape from occupied Europe. He worked at the Canadian nuclear energy project during the war and at the British project at Harwell after the war. In 1950 he was on holiday in Italy and abruptly disappeared with his wife and two sons. In 1955 he reappeared at the meeting in Moscow which I failed to attend. He was working as an experimenter in the Soviet accelerator project. He spent the rest of his life in Russia as a scientist in good standing, hampered by the Soviet bureaucracy that surrounded him. It never became clear whether he had been a Soviet spy in Canada or in England. He died in 1993. His biography was written by Frank Close and published with the title Half-Life (2015).
NOVEMBER 22, 1955
My own work continues to go well. I am beginning to move closer to a field I have for a long time dreamed of working in, the controlled application of thermonuclear (fusion) energy. I shall become a citizen in 1957, and I can start planning to go into secret work about that time. The work itself is getting rapidly less secret, and there is talk of making it completely open. It is no longer necessary to have more than the usual type of clearance to work in it. We are now allowed to mention that there is a big laboratory here in Princeton (connected with the university, not the institute) working on the problem. The director is an astrophysicist called Lyman Spitzer. What they are trying to do is to make a small artificial star. Spitzer is a good man for the job. The problem at the moment is not so much to build gadgets as to explore the basic theory, and I am well qualified to work on it. I believe I shall gradually get more involved in this kind of thing, and I find the prospect exciting. This week I had my first definite offer to work on such problems. It would have been a full-time job in California with a huge salary and an industrial environment. I said no to that. But I will have no difficulty in getting into the work part time without cutting myself off from academic life.
I never worked with Spitzer’s fusion project in Princeton. After sixty years the project is still active, but it never achieved its aim of producing fusion energy at a cost competitive with coal and oil. In my opinion, the whole fusion enterprise made a strategic mistake around the year 1960, when it moved too soon from exploratory science to large-scale engineering. After 1960 all the fusion projects were building big machines with a few fixed designs, intended to demonstrate economic production of fusion power. The big machines failed to be competitive, and there was no support for scientific experiments trying out radically different designs on a smaller scale. I was lucky not to become trapped in these fruitless attempts. Instead, I found more exciting challenges in the field of fission energy.
• 12 •
MOSCOW AND LA JOLLA
THE YEAR 1956 was mostly concerned with new ventures going outside my academic role at Princeton. The first venture was an international meeting of physicists in Moscow. I went to the meeting and spent a few days in Leningrad, fulfilling an ambition that dated back to my days as a schoolboy in England. It was a great joy to get to know the Russians, both as scientific colleagues and as human beings. The many hours and days that I had spent studying the Russian language were richly rewarded. Only by knowing the language can a visitor see below the surface of an alien society. The Russian language is the key to the Russian soul.
My second venture was starting a new career as a nuclear engineer. I spent the summer at La Jolla in California, where a group of scientists was invited to launch a new company with the name General Atomic, building and selling fission reactors in the commercial market. In three months we finished a preliminary design for a reactor called TRIGA, the name meaning Training, Research, Isotope-production, General Atomic. The reactor was a commercial success. The company sold seventy-five of them, mostly to hospitals and medical centers where short-lived isotopes were needed for diagnostic purposes. The TRIGA differed from other reactors because it was designed with safety as the primary consideration. Other reactors relied on engineering for safety. The TRIGA relied only on laws of nature.
My job in Princeton gave me unusual freedom to engage in extraneous activities. I always had a short attention span, jumping frequently from one enterprise to another.
JANUARY 3, 1956
We were lucky to have a long spell of hard frost, unusual for Princeton. Lake Carnegie is frozen over with ice eight inches thick. I bought Katrin a pair of skates and took her out to the lake with me every day. She has learned amazingly fast (the ballet must have helped her with this), and we have got along together famously. One afternoon we skated five miles together from one end of the lake to the other and back again. During this week I found time to finish my spin wave papers. I feel quite light-headed after five months with spin waves chasing each other around in my brain.
JANUARY 25, 1956
I have strong opinions about space travel, and I give them to you for what they are worth. Technically there is no doubt it is possible with existing equipment (given five or ten years for building and testing the machinery) to transport a group of people to the moon with enough supplies to last a year or two, and bring them back alive. The weight of oxygen needed to supply one man for a year is surprisingly small, less than the weight of food he will eat; if he stays longer than a year, he will grow plants which produce both food and oxygen. Meteorites; the risk of being hit is very small, except for the very small particles of dust which can be stopped by a thin roof.
The question how soon people will go to the moon depends on how much money and effort the human race decides to spend on it. It will certainly be expensive (estimates vary between ten and one hundred million pounds) and not immediately profitable. I believe it will go fast because of the psychological situation in Russia and America. Each side is convinced it has to get ahead of the other in such enterprises. It is probably true that to have an observation post on the moon with a fair-size telescope would be a military advantage for the side which gets there first. I believe the job will be done, by both
Russia and America, within the next twenty years, perhaps much sooner. And once the first trip is made, there will be no end to it, it will become as commonplace as flying the Atlantic.
This prediction turned out to be half right, half wrong. The last sentence is extravagantly wrong. I wonder now why I was wrong. Perhaps the main reason is that I grew up during World War II, when big enterprises were started and finished regardless of cost. I was still thinking in the wartime way. During the war, money did not matter. In peacetime, the political game was played with different rules. Money mattered.
FEBRUARY 13, 1956
Today I made a speech at the institute and let them have my spin wave theory for the first time. It went well. Oppenheimer and Pauli (from Zürich) were there and seemed to be excited too. On Friday I shall repeat it at Columbia, and later on at Pittsburgh. It is fun to go around with something new to talk about. The last two days I spent digging up information about Hermann Weyl for an obituary notice which will appear in Nature. The difficult part was deciding what to leave out, as they gave me a total of only 750 words. I could easily have written three thousand.
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