Please bear in mind that: a) this transcript is spoken word, rather than a literary work; b) the reader must bear in mind that this interview includes a person's memori which may offer a different perspective of a particular event. This perspective, in addition, may change over time due to life experiences. Disclaimer: This transcript was edited for occassional spelling and grammatical errors. The original transcript, unrevised, is available.

Hans Bethe

Second Series Interview

11-6-01

01:19 – We’d Like to ask you about your parents, how you came to science…

Well, my father was a physiologist, and I think a rather good one. I think one of his students was Meierhoff who, afterwards, became very famous. My father was especially interested in what he called the plastiguency of the nervous system. If you lose a hand, then the nerves adjust themselves so that that the function of that hand is taken over by other parts of the body. So that was a very interesting subject.

He was a professor in Frankfort, a place which now everybody knows and the only thing I did not like is that there were so many animals. There were so many dogs which were very noisy, and so the experiments in physiology didn’t appeal to me. The subjects, the center of the subject I found very interesting.

Now, my mother was the daughter of a professor of ear, nose and throat diseases in Strasbourg. I was then part of Germany and now part of France.

My mother gave me a lot of love, and that was important. She was a writer of fairy tales. She published a little volume of fairy tales, and then she published a play which also was a fairy tale which concerned a very curious young star which wanted to know what the earth would look like. And so, she fell down and so it then tells her adventures on earth. And on of the nicest lines I remember now is her father…the father of the star…is the moon. And, the moon has a servant and the moon would like to have a quiet Christmas so he asks at Christmas day, no, Christmas Eve, of the weather and the servant says: It’s snowing; you don’t need to shine today. And I thought, that’s a typical kind of thought of my mother.

Alright, so I grew up and from a very young age I was interested in numbers. I knew maybe at the age of five, maybe four I manipulated numbers. My father had a boss at that time. He, my father, was quite young. The boss sometimes liked to talk to me and one day he asked me what is zero-point-five divided by two. I was five. And so I said, “Dear Uncle Ewald that I don’t even know myself.” And the next time I saw him I ran right across the main boulevard leading out of town and said “Uncle Ewald, I know the answer.” So I was interested in numbers, most of all, so I thought I would want to do math. And that was already at the age of six or so. It was then later on, when I came to the university and began studying math that it turned out to be a very esoteric subject. It had nothing to do with real things or with nature; so that’s how I came to physics.

I had been interested in physics before, but it was really the way math is taught that made me decide this was not for me and I wanted to do physics.

08:48   So was there a real point in your life when you knew that physics would be your life or would it be gradual?

It was fairly sudden, so it was within a month or two of going to the university.

09:26  Did the teachers at that time influence you?

If he had, he would have pushed me away from physics because the main professor of physics at Frankfort was no good at all. But we did have a very stimulating teacher who was: Gerlach. He was interested in me and I was interested in him. But since he was very good, he soon became a full professor at a different university. And was replaced another associate professor. And that associate professor was a very good spectroscopist by the name of Meisner. Then, more or less discovered me and told me “this is a place where you can’t learn very much. You have to go to Munich and study with Sommerfeld if you want to get anywhere.”

So he wrote a very enthusiastic letter to Sommerfeld and Sommerfeld immediately accepted me as a student in his seminars. And, I chose my year of birth very carefully, namely I got to Sommerfeld very carefully and found a way to graduate study in 1926 just when Heisenberg invented Quantum Mechanics and Schrödinger was writing his papers on wave mechanics.

And Sommerfeld being a very famous physicist got all the galleys of Schrödinger’s papers before they appeared. The galleys were given to his graduate students and each of us had to give a talk in seminar. Most educating. You are not a teacher so, but to make them do and learn correctly and completely from the very source. So Sommerfeld made everyone take one of Schrödinger’s papers and report it. Usually parts of it. So I chose my entry into physics very carefully and stayed with Sommerfeld two years and a half and took my Doctors degree.

13:36 Then at some point you decided to come to America.

Well, it was decided for me. Continuing with Sommerfeld leads me to America. So I was famous enough so that all students, post-docs in particular gravitated to him and there was one young post-doc named Kirkwood, who was a well-known physical chemist, and one not so well known physicist, Lloyd Smith, who came to Munich and I had previously spent one semester in England.

So, Sommerfeld wrote me “You know English; you take care of Mr. Smith.” So I took care of Mr. Smith and gave him a rather nice subject to do which he did very well. And, so he was satisfied and returned to America, and specifically he was an instructor at Cornell.

Now came the Nazis in 1933. Since my mother is of Jewish descent I could not hold any government position. And every university in Germany than was and, I think still is a government position. Namely, the universities are run by the individual states. So, having been in Munich from the beginning of my career I am still getting a pension from Bavaria. And that’s very nice because they asked Heisenberg “when will Mr. Bethe become a full professor?” And he put it rather early…1940…and so, that my seniority and I get quite a substantial pension from Germany every year. Not so much now because the European currencies have topped about 10 or 15 percent compared to the dollar.

So, with an intermediate stop in England I came to the United States and right away came to Cornell because of my previous student Lloyd Smith.

Now, I should tell you one more thing about England. In England I stayed at Manchester where I was the substitute for the lecturer who was on sabbatical leave and who was also Rudy Peierls, my old friend from Munich. He was well established with wife and baby daughter. He invited me to share his house with him and I have seldom, except for Los Alamos, worked so hard and so steadily as I did as that year in Manchester.

Again, I chose that very carefully, namely, 1933. The neutron had just been discovered and that put nuclear physics on the map. So Peierls and I worked on nuclear physics at the very beginning. And, that was again a nice story.

The neutron was discovered by Chadwick at Cambridge. We both had been to Cambridge before a semester or so, and Chadwick invited us to come for a visit. And, so Chadwick had a very intelligent graduate student by the name of Goldharver who later on became the director of Brookhaven National Laboratory. So he gave Goldharver the problem of splitting the deuteron by the means of gamma rays. So, Goldharver did and Chadwick did and we looked at that and saw it was very interesting and they could measure the range of proton, and hence its energy.

And so at the end of the visit Chadwick told us: “Now I bet you can’t give a theory of that.” It took five hours by train from Cambridge to Manchester. So during those five hours, we produced the theory of this reaction, the photo-disintegration of the deuteron. And Chadwick later told us that he said this only to stimulate us, and that he knew perfectly well that we would be able to do it.

So, I had a very good time with Peierls in Manchester. He had then no students, while I had students to the extent that I gave lectures for about two months replacing the man who was on sabbatical. And some of those English physicists remembered my lectures later on. All I did was explain to them the basics of Wave Mechanics, which they ought to know after all.

This was a very fruitful time in England and after that coming to this country I found here at Cornell Stanley Livingston who, for a short time, consulted for Los Alamos. Stanley Livingston was a good experimenter who knew absolutely no theory. But he had a card file on all the papers on nuclear physics which had been published. So, it was very easy to find out what had been done.

So I told Livingston I gave a course on nuclear physics at Cornell and I was invited to several universities to give talks. That’s one of the wonderful things in this country that once you are in, you are invited everywhere. One of the places that invited me was Minnesota where, at that time, the Physical Review was edited. So the editor asked me couldn’t I write something for review of modern physics about nuclear physics because obviously I knew something about it and most people in the United States wanted to know about it and didn’t have the background. So, that was the basis of the, what is now known as, the “Bethe Bible” giving the fundamentals of those nuclear theories and experiments which were then known.

26:09 You stayed at Cornell, you must have had plenty of opportunities to…

I had calls to other places and let me tell about those. I knew from Munich, I.I. Rabi who was now at Columbia and already then one of the great men in physics. He had studied at Cornell and disliked it intensely. So he said “If you stay at Cornell…you will never amount to anything. You would have to go somewhere else.”

Now he, Rabi had a good friend, Whelan Lewis, who was the department chairman at the University of Illinois, and was later on at the Radiation Lab at MIT. When Whelan Lewis invited me to come, I gave three lectures I believe, whereupon he offered me a job, a full professorship. I was assistant professor at Cornell. Well, so that was very attractive, on the other hand the landscape is far more attractive here. And so I went back to Cornell where I said I have this offer…will you match it? And so…he did. That is our then president matched the offer, gave me a full professorship and doubled my salary which was then six-thousand dollars…after doubling, which means about 60-thousand dollars of today’s money. Well for a young man that was a lot of money and I was a young man and still under thirty.

So I continued my work here and got interested in building cyclotrons because Livingston wanted to build a bigger cyclotron and our department chairman was extremely interested in supporting nuclear physic, both experiment and theory. His name was Imps (?) no relation to the famous Imps. So we worked quite hard on designing the magnets for the cyclotron to be, which inevitably was built.

TAPE 2

2:00:16  So, you were telling me why you came to the United States instead of staying in England….

The answer to that is very simple. First of all, England is a small country. It has only a small number of positions and it has a very large number of intelligent people. And, therefore, competition for professorships is fierce and as such a foreigner didn’t have much chance. Probably I would have got a position. But, in the end, because my friend Rudy Peierls did and I might have been in this way also, which wouldn’t have been very nice. Then there was the last reason I had my position at Manchester only for a year and the beautiful collaboration therefore came to an end when I stood in the…England or went to the United States.

2:02:09  Is there anything else you could have seen yourself doing other than physics?

Let me first answer the previous question.

I had many, as it was, a moderate number, of offers. First, University of Illinois, then just after the war I was offered a professorship at Columbia. Columbia was quite interesting for one thing there was I.I. Rabi, but it was a generally a very good department. But, my wife and I had just had our two children and we said bringing up children in New York is a very chancy thing. Ithaca is much better. Then I had an offer from Berkeley, which is a very nice place, but I knew I would not get along with the other physicists at Berkeley.

Anyone in particular?

2:03:41  Ernest Lawrence. Now Berkeley, of course, was very attractive in fact we had been there for three summer months which was delightful as a place to live but then we only were dealing only with Oppenheimer and a few other theorists which was very pleasant. The place I was supposed to have at Berkeley was Oppenheimer’s. Then, I think I could have had a job at Cal-Tech for the asking but I did not. I was offered a job at Seattle which was to build up the Department of Physics, which had some good quite people already…but now is much better. But I didn’t believe that I was a good department chairman. I don’t really like the administration. I like the people at Seattle very much…I still do. I liked the scenery even better than here (Ithaca).

One of the great things is along the big highways it tells you every possible place; the trails that go off from there. It was perhaps one of the most difficult offers to reject. And then finally was the Institute of Advanced Study at the…Princeton where it was also difficult to reject. The main reason not to go there was that I did like to do teaching. I liked to have doctoral students which I had at Cornell, and that was not so obvious at the Institute.

Well, apart from that I had an offer from Birmingham in England and sort of an offer from Manchester. I had two offers from Munich…the position of my old teacher Sommerfeld which was occupied by another whose knowledge was completely devoid of physics. Then he was fired by the post-war German government and they tried to get Heisenberg which would have been a natural person to have. But there was, again, political intrigue against him so Sommerfeld offered me that job in 1947. Now in ’47, Germany was in a complete mess and I wouldn’t think of going there. But I got the same offer again in ’68 when Germany was recovered. I was really quite an attractive place, in fact, and then I got two offers from the university and the technical university. So, I got enough offers from Munich, then I got one from Tubigen where I had been sort of assistant professor as the last…both my first and last job in Germany of any standing and that was quite amusing how I was dismissed.

In 1933 as I told you there was in April, there was a law that nobody of one or more Jewish parents could be a professor. So, how did I hear about it? One of my doctoral students in Tubigen wrote me a letter and said: “I hear you have been dismissed, so what should I do?” So I wrote back to him…”that’s really not my business. You have to look out for yourself. But how did I hear you were dismissed?” So he sent me the newspaper in which it was published in a small town in Rothenburg. Not in Tubigen, not in Stuttgart and ten days later than that I got notice from the head of the department, and again a week after that I got the notice from the Rothenburg minister of education that I was dismissed and I could still be paid my salary for April.

2:12:30 That must have been a very painful period of your life?

It was a painful period. It was a…I did like Germany, but for several years Germany had been in terrible political upheaval and I certainly didn’t like the Nazis. And so, it was painful and yet, in a way I was quite happy to get away from it.

2:13:21 Did this period strengthen you views maybe on nuclear weapons?

No. Well…yes, I was very anxious to defeat Hitler. So once the war came which was ‘39, six years later, I wanted very much to contribute to defeating the Nazis. You will recall that America was not yet in the war in ’39, but only in ’41. So I was looking for a way in which I could be useful. So I thought maybe I would be useful to investigate the efficacy of the protection of warships. And so I got from the Encyclopedia Britannica the information on armor plates, and wrote a paper on the armor plate and penetration of armor plate by projectiles, being helped there by a good friend of mine who was Viennese refugee who had come through the department of civil engineering. Well, that was one thing and it was published and I know it was used in England quite a lot. (????????) was in this business who was a friend of mine in my English time. Then next I heard about the Radiation Laboratory and I knew something about electrodynamics and I thought that would be a good place to be. And, made that known to the people at the Radiation Lab but I didn’t yet have a clearance for work that secret. Fortunately, I became a citizen and could be cleared in the spring of 1941 and became a citizen exactly on Pearl Harbor day.  So I immediately got an offer from the Radiation Lab. I had promised to give some lectures but the, my future boss at the Radiation Lab said “Don’t you know there’s a war on? You can’t (anticipate your track). You have to come here.” So I came to the Radiation Lab as soon as the semester here was ended and had an interesting time, very interesting time at the Radiation Lab. I worked on……..I’ll remember that later.

But while I was at the Radiation Lab in the summer of ’42 I got a call from Robert Oppenheimer, whom I knew from meeting, telling me please to come to a theoretical conference involving nuclear fission. And, with practical applications, I think he said it somehow, himself, some way like that.

(Battery Change)

2:20:17   You were telling about your transition to war work….this led to Los Alamos?

Well, we are now in June ’42. Oppenheimer had been appointed in charge of fast fission, whatever that meant, to succeed Gregory Bright. Gregory Bright had been appointed to that job by Arthur Compton who was the director of the Chicago Laboratory but Gregory Bright was interested only in keeping everything secret. He was not interested in working himself or getting others to work on the advancement of the subject. And so Arthur Compton fired him. And Oppenheimer was all eager and so he assembled a group in Berkeley to discuss how you could assemble a nuclear weapon. And that group included Edward Teller, Oppenheimer’s collaborator Robert Serber, two of Serber’s graduate students, Frankel and Nelson, Von Veck, solid-state physicists at Harvard. Ah yes, Gunnar Pinsky, and myself.

Now, I had thought that an application of fission to practical purposes was ten years in the future. But, I stopped in Chicago as arranged and Edward Teller introduced me to the pile and told me that Fermi was making very rapid progress towards a functional chain reaction and I was shown the so-called pile which later on would give the first chain-reaction. So, it was obviously serious and with that I, both Teller and I, went to Berkeley to talk about the possible assembly of Uranium 235 to make a nuclear weapon. Well, that was very well, but it turns out that Serber with his two graduate students had already done most of the interesting work that we were supposed to do. And so instead of working on that, we followed Edward Teller’s lead to think about the possible use of a fission explosion to initiate a fusion reaction. We did a lot of pertinent things on that. It wasn’t the most interesting scientifically, most interesting work, but I was fully aware of two things. One being that this really was not for the second world war and second that I really didn’t like the idea of going to still greater energy. However, in the meantime we had a very fruitful discussion at Berkeley and more than that I had a very pleasant time in Berkeley. We had a house together with the Taylors and with Konopinsky. Konopinsky was a very broad-shouldered, very healthy-looking man. And the one room that was available for him was the young daughter’s room of the people from whom we had rented the house.

Some irrelevant thing…the only books that were in that house, which was a beautiful house…what a wonderful view of the bay and of San Francisco, when that was visible. The only books available were books, such as filth…porn which told you that if you had a dress on and served breakfast, you should not serve just four prunes, but five. Then, your guests will come back. And there were two more books like that – the very lowest of business. You couldn’t call any of them economics book. It would not make Economics 101. So our impression of the intellectual level of our hosts was on a low, but the house was just lovely.

Now, Konopinsky would get up at eight o’clock and go to the Lab. We would get up at nine o’clock and have breakfast. Outside in San Francisco was gradually appearing from the fog. And the Taylors would get up at eleven o’clock and we would never see them until after lunch.

Tape 3

3:00:30           So you attended these things in Berkeley and that led to Los Alamos?

So, yes. There came news from Chicago from Compton and Allison that they felt that we really should have a separate Lab for the actual assembly of a nuclear weapon because they at Chicago had their hands full using that chain reaction. And, in the meantime, General Groves had appeared on the scene who wanted things to really go forward. So, we went back home…for Teller Chicago and for me Boston-MIT. From time to time we got a visit from Oppenheimer. Usually he had trouble on the plane because the weather was bad and the idea got firmed up that there should be a new Laboratory and then there was question who should be the director. At least one person was named as director, but then Groves decided on Oppenheimer.

The point was that most of the people in the project at Chicago, in particular, never came out with a direct answer to any of Groves’ questions. For instance, the critical mass might be ten kilograms, it might be fifty, or it might be two. And so where Oppenheimer gave him straight answers…very useful for him in saying either he knew or he didn’t know.

So Oppenheimer was appointed director of the new Lab.  And then the new Lab had to be in a very secret place and Oppenheimer said “I know, and I’ll show you.” And showed Groves Los Alamos and it was Los Alamos and it was accepted.   There was a great turmoil whether we should all be in the army. Oppenheimer was very patriotic and he said “of course I want to be in the army.” But Rabi who was our advisor, always said “under no circumstances let yourself get into the army. Then you will have to go to the General to find out if you can put a screw here or there or none at all. And, because Rabi had been in the Radiation Lab had experienced talking with the armed forces. The Navy being bad, but the army was infinitely worse.

So essentially on Rabi’s experience and recommendations we were not put into the army, but were civilian, we were all civilians, but of course we had to report to general Groves.

Now, General Groves as you probably know was not a very pleasant person. In fact he was very disagreeable in personal contact but he was absolutely the most efficient person you could possibly put into that job. It was a very difficult job. He had to get material from Oak Ridge, which was the first Lab using the chain reaction, and from Hanford which was to the real production.

And then Ernest Lawrence insisted that the electromagnetic separation be used which was fabulously expensive, but did actually advance the day of Hiroshima by probably a month. Because, the diffusion method was very good and fast as long as you stayed with low enrichment. But, if we take just about the same amount of time to get from 90…from 50% to 90% as it had taken from 1% to 50%. But of course, the electromagnetic separation from 50 to 90 was child’s play. So, by the combination of the two, you could advance the availability of material very substantially.

So, it was decided to have the new Lab and have it at Los Alamos and to start in March of ’43. And Oppenheimer wanted to appoint Rose to head of the assignment of living space, so she went a week before me.

We didn’t have any children at that time and when we appeared at Los Alamos, both of us, it was a shambles. It was a construction site. You stumbled over kegs of nails, over posts, over ladders and nothing was finished. So the beginning was difficult.

However, Oppenheimer assembled some thirty scientists of some standing and we had a meeting lasting two weeks or so to discuss how to go about it. And, of course, Serber, and again was the man who knew and gave talks about this as well as probable efficiency and that is a published report very secret when we were there during the war. But, by now is published. I don’t know what the title is (The Los Alamos Primer)...Serber says, but it could very well be.

3:12:50 

So, we brought this thing together once the General came to give us a pep talk…totally unnecessary. We were all very eager to get ahead with it. Then the group, we assembled…transmuted, more or less, into the so-called Coordinating Council. You said (to Alan Bishop) you don’t have that. The Coordinating Council was probably the best invention by Oppenheimer. And he said every senior scientist in the project should know what’s going on. And so now as the Lab was organizing in divisions and then in groups, we should know as least as well as I do. So every group leader was a member, automatically of the Coordinating Council. And then there were some senior scientists who were not group leaders or were seen as consultants like John Von Neuman or G.I. Taylor from England who were automatically members of that council. But they were there only three days out of a month. Von Neuman and, much less, Taylor.

Having this council meant that every member of the council felt personally responsible for making the project succeed. I felt so particularly being a division leader and I think there was hardly any exception of that rule. Everybody felt “this is my project; I have to see to it that it succeeds.” And I believe this has never been sufficiently emphasized.

3:16:44 Do you think this was important to the technical success of the project?

This was very important technically because at the Coordinating Council many people came with problems. “We don’t know how to solve this problem,” then as likely as not, another member of the council would get up and say “Well, you do it this way.”

3:17:37 So this was an effective way of organizing science for complicated missions?

No, I don’t think so for complicated machines. For major projects which would lead to one goal but by having many machines was the way and their products.

3:18:40 What are your feelings on the evolution of nuclear power now that the cold war has ended? Does the public understand it?

The public, of course does not understand at all. We have to distinguish nuclear weapons and nuclear power.

First, nuclear weapons: I always thought during the war the atomic bomb would be used and indeed it was. I feel, today it was the right thing to do. I feel one of the results was saving millions of Japanese lives and maybe 100,000 American soldiers. Japan would not have given up without it until she was totally destroyed.

On the other hand, a nuclear war between the Soviet Union and the United States would be an absolute disaster. We each had thousands of weapons and with a hundred weapons, I think you can destroy the country so it cannot recover for years, quite apart from casualties. So I think one has to be very careful about numbers. Two weapons…ok. A country can recover from that as indeed Japan did very quickly. A hundred probably would be a disaster. I felt after the Japanese surrender that the public ought to know and we should talk about the importance and the consequences of the nuclear weapons.

I think we were crazy during the cold war to build ten thousand nuclear weapons and make them ready to delivery. No sense at all, but what would you do with it?

So, I think, we have gone far too slowly in reducing nuclear weapons and with the present disturbances of starting with the 11^th of September, this problem has been shoved back. I believe President Bush was ready to reduce weapons considerably, unilaterally, and I’m somewhat in favor of doing this because negotiations are terribly complicated, long, and controversial and even the simplest thing takes infinitely long time to do.

I was involved in 1958 in the scientific conference to determine the possibility of a nuclear test ban. And even though the Russians were very unpleasant within three months we had more or less agreed. But that scientists, once it comes to politicking, then it is a totally different mater. So, I think it’s rather a good idea to do it unilaterally and challenge the other side to follow.  But, I also think it is a good idea thereafter to make a formal treaty incorporating what you have already done. And, the treaty is there to be preserved and I think I completely disagree with President Bush in saying treaties make no difference.

That’s my, oh, and I believe that we should reduce to much lower numbers than have been talked about. Now, a thousand is being talked about…gets a little closer to reality. I think that Russia and the United States should each have no more than one hundred…that’s bad enough. But, I believe it is desirable for us to keep some and not to go to zero because there are ambitious countries like North Korea, Iraq and you never can tell what they will do. And it is a measure of safety to have them in the hands of less ambitious countries to have an overwhelming superiority like a hundred. And I hope we can get there sometime. Probably, not very soon. In addition top ambitious countries, there are of course persons who are absolutely vicious like Bin-Laden. That is a problem so much worse because it is entirely different from any previous war.

Tape 4- Stills of Bethe, early years Sots of Cornell

Tape 5 – Interview continues

5:00:48  You were telling us your views on Nuclear Weapons. What are your views on nuclear power?

I have a totally different opinion on nuclear power. I think it should be used much more. There’s one country that’s done it right, and that is France. I think they produce about 110% of their power requirements with nuclear power. The remainder they sell to other countries. So, how do the French do it? First of all it was financed by the state and that meant that interest during construction was much lower than it would have been with a private company. So, there are nuclear power plants much cheaper than ours. And secondly, they decided on one design. They built that one design about five times and they found what was wrong with it and then they made a new design and they built that maybe six or eight times so they could prove their own design all the time, thereby improve the functioning of these plants.

The only thing I see wrong with nuclear plants is their cost but with the increase in cost of fossil fuel and particularly natural gas the use of a natural gas plant is just as expensive as a nuclear plant. One great advantage of a nuclear plant is that the fuel is very cheap. And it becomes cheaper once we decide to reduce our armaments. So there is lots of high grade 235 available just waiting to be downgraded by mixing it with ordinary uranium, thereby making it useable for nuclear power plants.

The safety of nuclear power plants has been investigated very carefully by the Atomic Energy Commission and repeatedly ever since so I think the safety is excellent. I’m very unhappy when I hear the Three Mile accident mentioned in the same sentence as Chernobyl. Chernobyl was a total destruction of the power plant brought about by the accident which left tons and tons of the reactor material flying around northern Europe. In Three Mile Island from the statistics we are not sure whether no person contracted any cancer or one person. It was half a person expected and, of course, nobody knows who that half-person will be. But, at least, essentially negligible. And so I think it is quite wrong to mention the Three Mile Island in the same breath as Chernobyl.

5:06:30

Now, in the meantime, reactors have further improved in safety so there is a…no safety risk and I would happily live next door to a nuclear power plant. Not so happily near a coal plant, power plant because there I get some of the soot going my way. So I think the safety of nuclear power plants is better than any of the competition.

I believe much better than wind power plants because windmills can disintegrate. The propeller can hit a person. I can think that kind of accident, while it is very small, I think it still is greater than the risk of an accident from a nuclear power plant. Though I believe from the safety point of view the nuclear plants are much to be preferred. Then one has to consider that they make no global warming. They don’t make any gases which contain the heat of the earth. They will not contribute to the warming of the atmosphere. Finally, if one takes the nuclear material available you can have power for centuries and if you build breeders, which I strongly advocate, then the nuclear power will surely be sufficient for many thousands of years.

5:09:41 What are your current views on nuclear testing?

In ’57 I was a member of the Presidents Advisory Committee and we wanted to do something towards disarmament. So I proposed a test ban. I’m not usually mentioned in that connection but it was in the meeting that small committee.  The result of that meeting went to President Eisenhower who was delighted because he was under pressure from the British and the Russians to stop nuclear testing. And so after our report he could propose it as his idea.

Unfortunately, Eisenhower was not a very strong President. He was, in my opinion, a good President, perhaps the best we have since Truman, who in turn was the best we have had since Roosevelt. So Eisenhower was very intelligent. I remember a session with him in which he immediately understood the proposals which our chairman, I.I. Rabi made to him and acted upon them.

But, when there was any controversy, he was not a strong president. He did not press his own opinion against some opposition, which of course, is somewhat regrettable. He ought to have faced the enemy face on and he regretted it the end of his Presidency that this was one thing he failed to accomplish namely, the nuclear test ban.

Now, a partial test ban was obtained under Kennedy one year before his assassination and this partial plan prohibited all testing in the atmosphere or in the ocean and Nevada. I think we haven’t done any damage to peoples from radiation. And somehow, people looked at the test ban the wrong way. They thought of only avoiding radioactivity from testing, instead of the important thing is to avoid a nuclear war.

5:13:42

Now we have had over a thousand nuclear tests, the Russians have had about half as many. But, still is an unbelievable number. So, we ought to have, at least, every type of weapon that we can want about ten times over and so in my opinion a test ban would not damage the interest of the United States weapons establishment.

But, we still haven’t got it and of course if we have it, the test ban, we should honor it and I am very unhappy to hear occasionally statements where well, “This is fine, but it’s just a piece of paper.”

A treaty is not just a piece of paper; it must be honored.

5:15:51 Would you reflect on Los Alamos as a scientific institution since you’ve been associated with it for almost 60 years, and its work in Stockpile Stewardship?

Well, I understand Los Alamos has a number of excellent devices. Radiation and similar devices. I wish it can make sure that a given weapon is in order. The other possibility is what Oppenheimer answered when he was asked a similar question, namely…you open the bomb and look inside. If every piece of metal is alright then you can be pretty sure that this weapon will work as advertised. If part of it is rusted away, you better take it apart and rework it.

5:17:28 You think Los Alamos still has a role to play for the nation?

I think Los Alamos has a big role to play, this being one. I think Los Alamos has done well in Stewardship and will continue to do well.

5:18:16 Do you think there are new directions for science to go in the next century as great as the last century?

A hundred years ago some of the greatest physicists said “Physics is at an end.” I have seen such statements in the proceedings of the Royal Society. As we know very well, Physics just started at that very time and took wonderful leaps, some of which Los Alamos has been involved in. So, I think physics is not at an end today. We have to understand why mesons and quarks work the way they do and there is a lot to explore.

The greatest future, I think, is in biology and I’m glad that Los Alamos has gone more and more into biology. I would like to know how my brain functions. I don’t believe it is against the uncertainty principal. I think it is possible to explore this and I suppose there always will be a duality between our own experience when we think and on the other hand the brain waves that can be measured, that one can measure. Brain waves, nobody a hundred years ago could have believed. And we have to find out why the NDA (DNA) works the way it does. What does the alphabet really spell? What properties can you read out of the NDA (DNA) of a person so, there is perhaps centuries of work in biology.

5:21:59 It sounds as if you would have entered this field yourself?

I would love to if I was 25 instead of 95. That’s what I would do.

5:22:28 Is the study of physics something that could be useful in the study of biology?

Science is science. One just has to ask the right questions and think for some time how to attack them.

5:23:07 What was exciting to you about the study of stars and supernova?

That they’re there. Stars are there, they shine the sun gives us life and warmth and makes plants grow. And this is absolutely necessary for life on earth and for anything. So the energy from stars is an essential part of our life, a basic part of our life. So we want to know all that energy is made. Now I found out in 1978 that their energy is made from nuclear reactions. In fact, that was believed already for at least ten years. Before that it was hard to tell which nuclear reaction.

Similarly, nuclear reactions are necessary to make the elements we see. Back in ‘38, people wondered about that. In ’38 we didn’t know enough to answer that question. But now, we know that a star in its own age becomes a giant which means a very dilute body, but the core of that star is much denser than the center of the sun. As a matter of fact, the two things are related: the big total size and the small size of the core. In the course of its evolution, the core becomes denser and denser. Finally it becomes dense enough so that you can have a three-body reaction. That was found by my colleague here, Ed Saltpeter for which he got a prize from Sweden similar to the Nobel Prize. Saltpeter and Hoyle, the English physicist who died a few weeks ago.

So, there is a three-body reaction…three alpha particles can meld together and become carbon 12. This way for Helium to Carbon 12 was not rigid in 1938. Nobody knew how that could possibly happen because all the intervening atomic nuclei are just barely stable and are present in very small quantities. What you have to do is make the jump from helium to carbon 12. After that, you can do just whatever you please to add alpha particles or you add protons one by one. And that process goes on in stars somewhat bigger than the sun but not a great deal as is known as the S process. That was found out in the 50’s very soon after Saltpeter and the names are Burbridge, Fowler and Hoyle. Hoyle again. William Fowler was a delightful man, full of fun who, either himself or through his staff investigated nearly all the possible nuclear reactions which can play a part in the stellar energy. And he was one of the factions of Cal-Tech and one of the reasons why I went there very frequently in winter. Unfortunately, he is dead.

Tape 6

Well, from time to time in the sky, the sun flare of a star which then makes it emit about as much light in the week as the sun does during its lifetime. And this, theoretically, is exciting. The phenomenon is called the supernova and the last one that could be seen by the naked eye occurred in the southern sky in 1987. And that was very fortunate because by that time we had accumulated enough knowledge so that we could interpret how the phenomenon in the supernova in detail. There is, especially a physicist in California who unraveled both of these problems. Now, looking at it from the theory point of view, the star becomes a giant who uses up all the nuclear fuel that it has. It makes Hydrogen into Helium into Carbon and so on. It stops at iron because as we have known for as long as I’ve been in physics is the most strongly bound element of all. So therefore from iron, you cannot get any further nuclear energy. And that means the center of the star is prone to cool down and when that happens, there is no force opposing gravity. And so, once the center of the star has become iron the star is bound to collapse and that sets free a very big amount of gravitational energy. Gravitation is what Lord Kelvin believed was the source of stellar energy. He was wrong, but at the end Lord Kelvin triumphed a hundred years after his death because in the end for a big star, gravitation collapses the star.

So, that much is easy to understand and it’s generally believed that having released that much gravitational energy. That energy has to come out again. So, there’s recoil and a large part of the star is ejected. As a matter of fact, we know that the center of the star, the core, which collapses is about the mass of the sun. And we can see these remnants of supernova and that is observed by a laboratory at Araceibo in Puerto Rico which is directed by Cornell University.

So, the beginning of the history of the subject was that Araceibo observed the source in the sky which emitted microwaves at a regular schedule…30 times a second. And first people believed “at last we have found our cousins, and our cousins are trying to give us a signal…30 times a second.” Then it turned out the source of these was as hot as the sun and so it was unlikely that our cousins could live there and instead it was proposed by Thomas Gold who is another astronomer here that the star has become a neutron star. In other words, it has collapsed and now consists of neutrons which are held up by the Pauli Principal. We have a fermigas of neutrons which because of its temperature…pressure can be held up against gravity. These neutron stars have been predicted previously. Probably, most accurately by Oppenheimer and Snyder approximately 1930, or thereabouts.

One can calculate just from Quantum theory that neutron stars have a radius of approximately ten kilometers so they are very, very dense. And then you can make very wonderful science fiction about living beings which might crawl along on the surface of a neutron star.

6:09:54 You’ve been so instrumental in so many things. Is there anything you would have liked to do that you feel you didn’t?

Well, I would have liked to actually like to explain supernovas, but after many papers…some of them by me…mostly by other people, it turned out that our ideas about the mechanism of a supernova were wrong.  That was shown about a year ago, so it’s back to the drawing board. And I hope some people find a solution but I think you as division leader should encourage your astrophysics group to finally find the mechanism of a supernova.

6:11:28 We are going to interview your wife so I wanted to know if you had any first memories of meeting her.

I do indeed. After I took my doctorates degree, I became an assistant to P.P. Ewald who happened to be her father. So I spent one semester at Stuttgart which, from a personal point of view, was the most enjoyable semester I spent, at least in Germany. Rose was 12 years old and her elder brother was three years older and so their parents, P.P. Ewald and Emma, thought their assistant to the professor was to assist in every way including taking the children for Sunday walks.

So, several times I took her and her brother for a Sunday walk which I enjoyed very much. The two youngsters were very lively and we had good conversation and they knew good places to go, so there I was. And then there were two younger children and so we went once with the whole family and took a train to Marbach which was the birthplace of Fredrich Schiller. And now we had to catch a train going back to Stuttgart.

So the station master told us it would take an hour to the next train, but fortunately many German and Swiss railroad stations, there is a timetable right on the platform which I looked at. And it turned out on Sundays there was a train within 20 minutes. So I announced that and that really established my reputation in the Ewald family.

6:15:21 I wanted to give you something which I think you may remember. This is a T-Division roster from May 10, 1945. This probably has many names which you remember well. You can see your name well, here.

Yes, and Wesikopf, deputy leader, and Von Neuman as a consultant. Now, Von Neuman, as you probably know, was a consultant for the Lab, and was probably the most intelligent man I have ever met.  It was unbelievable how he operated. And, he was extremely useful to us giving us advice and he taught me several little tricks in mathematics which I had completely forgotten. It was one thing about differential equations that turned out very useful.

Now then there’s Rudy Periels, very good friend of mine…England, then professor at Birmingham, afterwards, professor at Oxford. And he unfortunately died.

And then group T-1 had two sections. One is Robert Christy and the other is Klaus Fuchs. Klaus Fuchs became well known, probably better than any of us all over the country in a rather unfortunate way. He was a very good physicist and also a very hard worker and he used to work later than most of the lab. Most of the lab went home at 5, and at 5:10 Klaus Fuchs came to me and told me what he had discovered. And that was all very useful about implosion.

Robert Christy is a delightful man who has had a long history. He had been at Cal-Tech most of his life and for many years he was the Provost at Cal-Tech. We were friends with them and each time we go there, which unfortunately for me is ended, but…

Then there’s group T-2. Robert Serber, as I told you, knew everything. He had worked on nuclear weapons with Oppenheimer and for Oppenheimer and gave the introductory lectures to everybody at Los Alamos. And there are many people in his group that I remember, especially Lauber (?) who was a well-known physicist at Harvard, then number three equally full of friends in people. Victor Weiskopf, the group leader who was also deputy division group leader. And, he’s probably my best physics friend from about 1937 on.

Marshack was alternate leader, also a very good friend and very enterprising who became a professor at Rochester but then became president of City College (NY) which is the graduate, the most important graduate division of City College University of New York. It’s marvelous.

And then I must certainly not forget Richard Feynman. Probably, the most creative member of the theory division. Then, of Cornell physics department. It was here at Cornell that he developed his method of doing quantum mechanics which is now used by everybody and that he found the magnitude of the Lamb shift in the hydrogen atom.

Then the biggest group was number five under Don Flanders. He was one of the very few people in the division that was older than I and he was a lovely man again to work with. And, he had an enormous group.

Group 6 was Nelson and Metropolis who were the leaders. They were in charge of the IBM machines which were then working on punch cards and Goldharver (?) who I mentioned previously talked about the people who worked on these machines as my “card-carrying” PhD’s. So the card carrying PhD’s were Nelson, Metropolis, and Feynman. Metropolis I hear died recently. Feynman, unfortunately, died much, much earlier about at the age of 70.

And then, two more groups…Group 7 with Hirschfelder as the leader, and T-8 with Placheck as the leader and Carson Mark as one of his group members, who then afterwards became the division leader after me and before you.

6:25:39  So, I’ve heard that during that time it was not theoretical physics but engineering that got the job done.

Our theoretical physics during the war was indeed mostly engineering, almost entirely. And I enjoyed engineering.