The Manhattan Project

Raymond Sheline's Lecture

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Raymond Sheline's Interview

Raymond Sheline was a chemist who worked on the Manhattan Project at Columbia University, Oak Ridge, and Los Alamos. Sheline received his Ph.D. from the University of California at Berkeley in 1949 and was a professor at Florida State University for 48 years. Among other accomplishments, he helped establish a nuclear chemistry lab at the Niels Bohr Institute in Copenhagen and published more than 400 scientific papers. In this lecture, Sheline discusses how he initially joined the Manhattan Project, his work on gaseous diffusion at Columbia University under Nobel Prize winner Harold Urey and how he became a member of the Special Engineer Detachment. He also delves into the history of nuclear physics, providing an overview of key discoveries and personalities including J. Robert Oppenheimer, Enrico Fermi, and Edward Teller.
Manhattan Project Location(s): 
Date of Interview: 
1995
Location of the Interview: 
Florida
Transcript: 

[Many thanks to Jonathan Sheline for donating this video to the Atomic Heritage Foundation.]

Raymond Sheline: This talk today gives me a certain amount of anxiety, because it’s different than any other chemistry talk I’ve ever given. First of all, it’s kind of autobiographical, and that’s always a little embarrassing. Secondly, it’s maybe more nearly the history of science than science itself. However, it is appropriate, because we’re just fifty years since the testing and dropping of the atom bomb in 1945.

Well, let me begin, then. With the attack of the Japanese on Pearl Harbor in December 1941, suddenly things were totally different in American universities and colleges. There was no longer a free, relaxed sort of attitude. Suddenly, because of the war, things were really different. 

I was a junior, a third-year student, at Bethany College, which is a small liberal arts college in West Virginia. I was studying chemistry for my major, with math as a minor. Now, because I took an overload all the time, in view of the war, it was very easy for me to complete my degree a semester earlier. I got my bachelor’s degree in January 1943. Also, I was a good student. I graduated summa cum laude, the top in my class. Because of this, I received an offer from Urey, Harold Urey, to work in the Division of War Research at Columbia University. Of course, I was very excited about that, because Harold Urey was a Nobel Laureate, having discovered deuterium.

When I got to Columbia University, I almost never saw Harold Urey. [Audience laughter] This is a picture of him, the way he looked when I did know him much better at the University of Chicago, after I’d gotten my doctorate.

I’d like to tell you a little bit about Harold Urey, because I want you to get a feeling for the scientists that are involved. Harold Urey was a fairly poor farm boy who grew up in Montana. He went to Montana State University and had a double major in chemistry and geology. He didn’t have enough money to go on to graduate school, so he took a job working briefly first in an industry, but then mostly teaching in high schools, and finally teaching at his alma mater at Montana State University.

So then, he had enough money and he went off to the University of California at Berkeley. When I was a graduate student there, one of the little tidbits that people talked about from time to time was the fact that Harold Urey had succeeded in having the shortest PhD dissertation. I don’t know the exact size, but it was supposedly only about ten or twelve pages. [Audience laughter] Mike [Kasha] says about thirty, so you see, I was exaggerating.

Anyway, while he was there, he learned of a very strange puzzle. People had been doing electrolysis for years and years, and somebody chanced to measure the water that kept being added to this electrolysis system. They found out that it had a higher density than normal water. It was called heavy water, but even with purification, that density continued, and nobody understood.

Harold Urey, in a series of brilliant experiments, was able to prove that what was happening is that the deuterium concentration in the water was increasing. At that time, it was not even known that there was a deuterium isotope [a hydrogen atom with one neutron]. He discovered deuterium, and for this he won the Nobel Prize.

However, I’m getting ahead of myself. I want to go back, now, before I was even a student at Bethany, to about 1934 and ’35. At that time, Enrico Fermi was doing experiments in Rome, bombarding uranium with neutrons. Let me tell just a bit about his reasons for doing those experiments.

It was known at that time that if you took phosphorous-31—I think I will start a little bigger—phosphorous 31, atomic number 15, and bombarded it with neutrons, you got a radioactive isotope, phosphorous-32, which is used very much today even, in biological experiments. But that phosphorous-32 beta-decayed to sulfur-32.

Now, look what happened. You see, we started with atomic number 15, and we went to atomic number 16 in this procedure. In an incredibly brilliant but simple idea, Fermi said, “What would happen if we took the very highest atomic number that we know, uranium” —that was the highest then— “and did the same process?” His idea was, “Take uranium, let’s say 238 [atomic mass], 92 [atomic number]. Bombard it with neutrons, get a radioactive uranium-239. Then, maybe, that uranium-239 will decay by a beta-minus to give a new element with atomic number 93.”

His idea was to make a new element beyond the then-known periodic table. Simple and brilliant. That’s what Fermi was doing, and what Fermi did was find a whole series of new radioactivities. They [Fermi and his team] were extremely excited. They called them eka-uranium-1, eka-uranium-2, eka-uranium-3. They said they were making a whole series of new, man-made elements. Well, for this and for his work on beta decay, Enrico Fermi won the Nobel Prize. Now, it turns out that what he had done was wrong. His interpretation of what he had done was wrong. We’ll look in a minute why that is so.

However, what I would like to tell you first is a little bit about Fermi. Enrico Fermi was an Italian physicist who, at a very young age, became professor at the University of Rome. For my personal belief, at least in my personal belief, he was the greatest combination of an experimentalist—here he is doing experiments with tubes and so on, old-fashioned tubes—and theorist, shown here giving a lecture. He was a very good theorist and teacher. I heard him give many, many lectures. Here he is with his graduate students. That particular one is [Emilio] Segre, who also won a Nobel Prize. 

However, what I should tell you know is that, of course, all the chemists, particularly the nuclear chemists, were very, very anxious to find out what the properties of these new elements were. Here were all these new elements that Fermi had discovered. They wanted to find out what the properties were. Of course, they were all looking.

One of the most brilliant was a nuclear chemist by the name of Otto Hahn shown here. He, together with his student, Fritz Strassmann, studied all of these elements, cool elements, which Fermi had made. They were able to prove conclusively that, in fact, Fermi hadn’t made any new elements at all, even though he’d won the Nobel Prize for this. What he had done instead was split the uranium nucleus into two pieces. One of those pieces, the one that Otto Hahn and his student, Fritz Strassmann studied especially, was simply barium.

This work was published in January 1939, and it caused a sensation. One of the people working in Berlin with Hahn was Lise Meitner, shown here. She was a sort of assistant, or maybe we’d call it a post-doc now. She realized something that Hahn didn’t realize: that because the mass of uranium was what it was and the mass of the two pieces into which the uranium broke were what they were, there would be a considerable loss of mass, and that mass would have to turn into energy. She predicted, together with her nephew, Otto Frisch, that fission of uranium would create a tremendous amount of energy.

It was just at this time that Hitler began to increase his persecution of the Jews, and both Enrico Fermi and Lise Meitner immigrated. Fermi used his Nobel Prize lecture and so on to leave Italy, and Lise Meitner—Fermi went to the United States; Lise Meitner to Sweden.

As soon as Fermi got to the United States, he initiated a series of experiments, which were also going on in other places, to find out if the idea of Lise Meitner was correct. He used some fairly simple equipment and showed very quickly that huge amounts of energy were released with each fission, about 200 million electron volts, whereas an ordinary chemical reaction is pretty energetic if it has one electron volt.

Just at this time, Niels Bohr—shown on this next transparency, skiing at Los Alamos—realized that it was not uranium-238, the main isotope of uranium, but a rather rare isotope present in only 1 part in 140, which was the species which was fissioning.

But since I have Niels Bohr up here, let me tell you a little bit about him. I was fortunate enough to be in his institute from 1955 to 1958, while he was still alive, and I got to know him really quite well. In fact, he offered me a professorship in his institute. My wife Yvonne and I loved the Danes, and were really extremely happy in Denmark. But after thinking about it, we wanted our children to grow up as Americans. Irrational, but that’s what happened. [Audience laughter]

Anyway, Niels Bohr was a very athletic man, fairly small with a huge head. You can almost see on that picture. Really, a very, very large head. In fact, let me tell you a story about that. When he and his brother, Harald, who was a famous mathematician were young, their mother took them out for walks and so on. They overheard another lady saying, oh, how sorry she is for that poor mother who has these two hydrocephalic children. They didn’t have so much water in their heads as they had brains. [Audience laughter]

I should also tell you, I guess, that Niels Bohr was on the national Danish soccer team. He was a very, very good athlete. In addition, he was a very kind man. He used to always invite the children of the guests at his institute to his magnificent home, furnished by the Carlsberg Brewery, and he played Santa Claus for these children every Christmas.

I should tell you that when it came to scientific things, he was very stubborn. For example, we once had a visitor, Professor [Rainer] Blatt, who was a famous nuclear physicist. Some of you might know the book, Blatt and Weisskopf, a famous physics text. Blatt came to give a lecture on superconductivity. This was before it had been explained by our own [John] Schrieffer], together with Bardeen and Cooper.

Professor Bohr, who wasn’t so often at the institute those days because he was head of the Danish Atomic Energy Commission, came personally to introduce Blatt. He said how very pleased we are to have this brilliant physicist here to tell us about superconductivity, and introduced him in a very nice way.

Professor Blatt began to lecture, and after about fifteen minutes, Professor Bohr got up and in a very halting, kind of apologetic way, said how grateful they were to have this famous physicist here to tell us about superconductivity. But he wonders if he [Blatt] had taken into account appropriately the interactions of the electrons. He wrote a few things on the board and sat down.

Then, Blatt went on just as if Bohr had said nothing. In about five minutes or so, Bohr got up again. Again, he kind of apologized and after thanking him for coming and so on, he said he wonders if they’ve taken into account appropriately the interaction of the electrons. Again, Blatt went on as if nothing had happened. 

For a third time, Bohr went through this procedure. This time, Blatt said, “If I’m interrupted again, I’ll have to stop.” In just about two minutes, Bohr was on his feet again, saying, “We’re pleased to have him, but he wonders if he has considered appropriately the interaction of the electrons.” [Audience laughter] Bohr sat down, Blatt sat down, and the seminar was over. [Audience laughter] That’s probably a little faster than the seminar today. [Audience laughter]

Anyway, I just told you that Bohr had figured out that it was uranium-235, present in only 1 part in 140, which was responsible for fission. At about this same time, people did experiments and they were able to show that two or three neutrons were given off with each fission. That meant that it was possible to have a self-sustaining chain reaction and to have a bomb or a tremendous energy source, perhaps.

With this idea in mind, Albert Einstein wrote a letter to President [Franklin] Roosevelt, urging that a crash program be undertaken to develop an atom bomb before the Germans, who had discovered fission, got there first. The next transparency shows Albert Einstein together with Lyman Briggs, who was at the Bureau of Standards, the man who was appointed by Einstein to decide whether or not to do this. It took Roosevelt fairly long to do this, but he finally succeeded and they decided it was appropriate to go ahead and do a crash program.

Now, I want to go back to Harold Urey. It was recognized that if they were going to do this, one of the ways they needed to proceed was to be able to separate uranium-235 from uranium-238. Because Harold Urey had won a Nobel Prize for separating isotopes, he was thought of as the ideal man to lead this project. That’s exactly what he did at Columbia University.

I’ve already told you a little bit about him, but now let me tell you a little bit about how he was as a scientist. I got to know him at Chicago, as I said. Harold Urey had extremely broad interests. I’ve already told you about his interest in separating isotopes, for which he won the Nobel Prize. He also developed what was called the Urey-Bradley potential. It was a potential energy service, which Mike Kasha would know all about, for molecules, really.

He also developed something that was very important in the early ideas of how evolution might have gotten started. He had the idea that if you took ordinary, inorganic chemicals and put them together with electricity or heat, things like hydrogen or carbon dioxide or, maybe carbon monoxide or methane and ammonia, that you would get the byproduct, not the raw products, for evolution. You would get amino acid, and some of the other species. That was done together with his student, [Stanley] Miller.

He also was interested in the geology of the moon. Since we were sending people to the moon, he thought it would be very interesting to predict what the surface of the moon was like.

But now the important point. Although he had these broad interests, you would think he might go from one to the other. As he hit his head on the wall with one of them, he’d go to another, back and forth. That was not at all true. When he was studying one thing, he studied it to the exclusion of everything else. He studied it on and on and on, ad infinitum.

Under Harold Urey’s direction, three different methods of separating uranium-235 from uranium-238 were undertaken. Two of those methods produced such a small amount of uranium-235, although very pure, that they were fairly soon discarded.

The other method was the gaseous diffusion of uranium hexafluoride. That happened to be the one I worked on, and I have a slide here which describes very briefly the idea. What you do is you take the uranium consisting of these two isotopes, especially, and make a gas, uranium hexafluoride, of it. Then, you make it diffuse through tiny orifices. The uranium hexafluoride, U-235, diffuses faster because of its smaller mass.

Now, if you wanted to get uranium-235—which is 90%, say, uranium-235—and you start off with only 1 part in 140, you need to get a total separation factor of nine times 140, which is 1,260. The separation factor you get from a single pass through the orifice is just alpha—you can look it up in any physical chemistry book—the square root of the ratio of the masses, which is 1.0043. You can see that you need to make a tremendous number of diffusions before you get anything at all pure.

It’s an extremely tedious, difficult process. It takes a huge plant, shown on the next transparency. This is the plant at Oak Ridge, Tennessee, which went under the code name during the war, because it was so secret, K-25. It occupied something like forty acres, so it was really a huge thing.

Now, at Columbia, as I said, I worked on this project. My particular part of the project was to test the corrosiveness of uranium hexafluoride. I built a kind of pilot plant, which circulated uranium hexafluoride around and around and around, and looked at the corrosion and the erosion of the uranium hexafluoride. In fact, I remember thinking at that time, “Why did I study chemistry? I should have studied plumbing!” [Audience laughter]

I should probably also tell you about how this was at this time. There was incredibly intense security. The main way that security worked was, they had each little group with its own particular problem working. But there was no contact between any of those groups so that nobody knew, really, what they were doing. We didn’t know what we were doing at all for a long time. There were all sorts of weird rumors. Finally, the head of our group illegally told us what we were doing.

One other thing. I went to Columbia in January 1943 and, in July of that year, I got drafted into the Army. The Army itself sent a Captain Grotchens to my Board of Appeals at Columbus, Ohio, to tell them they should not draft me because I was very important to the war effort. The people at the draft board, they said to Captain Grotchens, “What is he doing that’s so important?”

Captain Grotchens said, “I don’t even know myself. But it’s very, very secret.”

The draft board said, “We have draft quotas to fill and if you can’t tell us, we’ll draft him.”  

I was drafted. I was told by the Army, “Whatever you do, stay in the Army. Don’t go into any of the other services like the Navy or Air Force or something like that.”

I took tests when I got into the Army—I think everybody did—and I did well on them. I was offered commissions in both the Air Corps and in the Navy. The officers who offered these to me were absolutely astounded when I turned them down.

Now, an alternative to the production of uranium-235 was developed by Fermi, and it was his original idea. Here it is on a transparency. If you bombard uranium-238 with neutrons, you make uranium-239. The uranium-239 beta-decays in two successive steps, giving two new elements, neptunium and plutonium. The neptunium is very short-lived, about a day or so, and the plutonium is about 24,000 years. If you note, the plutonium is just one alpha particle [helium-4 atom], two protons and two neutrons, heavier than uranium-235. It was believed that it would be fissionable and, sure enough, it was.

You may say, “If this is right, Fermi had the right idea to begin with. Why did he have all this trouble? Why was he wrong?” Well, it turns out that uranium-235 fissions with such a high cross-section that all the activities which Fermi saw were radioactive fission products, and not this process.

But anyway, underneath the football stands at Chicago, the University of Chicago, Fermi built a reactor to produce plutonium to test out this idea, and he was able to produce plutonium. The exciting thing about this is that the plutonium now is another element and is therefore fairly easy to separate chemically from the uranium. You don’t have to go through this terribly tedious isotope separation. Nonetheless, both procedures proceeded. We had this big K-25 plant, so uranium-235 and plutonium-239 were both made.

Let me tell you a bit more about Fermi. I got to know him fairly well at Chicago after the war. He was at Los Alamos. In fact, at Los Alamos at this time, was the greatest gathering of scientists as probably has ever occurred and may ever occur. It was an incredible gathering of scientists.

At the University of Chicago, Fermi had a kind of informal seminar every Friday afternoon, and people would come together. He would point to somebody and say, “What have you been doing recently? Tell us.” At the beginning of each period, when Fermi was getting ready to choose somebody, the graduate students and the young faculty were all ducking down, trying not to be called.

One particular day, Enrico Fermi asked Maria Mayer what she had been doing, to tell us about her [inaudible] magic numbers. In 1948 [inaudible]. What she found is that certain numbers of neutrons and protons, number of mainly 2, 8, 20—she didn’t have 28—50, 82 and 126 neutrons and protons were unusually stable. On this particular day that Fermi called on her, she said, “I have found, using a quantum mechanical particle in a box, a way to explain some of these magic numbers.”

She didn’t use [inaudible 0:31:16]. She used the infinite square well particle in a box. She said, “I can get 2, 8 and 20, but then I get 40 instead of 50, 70 instead of 82, and 112 instead of 126.” She said, “The surprising thing about that is that there’s a sequence in the differences: 10, 12 and 14.” Everybody was kind of discussing this. There was a model by Malinka, which had a [inaudible] potential, which could, maybe, explain 50.

Later in the discussion, Enrico Fermi said something, which passed right over all of our heads, but it shows his incredible brilliance. He made a very simple statement and didn’t [inaudible]. He simply said, “Why is it that the [inaudible] should be so strong in nuclei?” You see, he had already recognized that the strong string coupling was involved and he went to [inaudible]. “Why is it so strong and so much stronger in nuclei, say, than in atoms?” If we’re able to make this, we are, say plutonium-239 and uranium-235, it’s necessary then to somehow make a bomb.

You may be interested in the mindset of the scientists who were working on this project. They worked extremely hard, probably 60 hours a week or more. The reason was that we were convinced that Hitler had a good chance of getting there first. In fact, Hitler was making speeches all the time, and we were hearing what his speeches said. For example, he was saying they had a [inaudible]-timed buzz bomb, which was a plane loaded with explosives which would go over to England and drop and explode. It was called a V-1.

Hitler was saying, “I have a much more destructive weapon,” and they were sure he was talking about the atom bomb. But in fact, he was really talking about the V-2, the rocket bombs. They never really came that close [to developing an atomic bomb], as we found out after the war. But, at the time, as far as we knew, he might be very close.

Meanwhile, in May of 1945, I moved from Columbia University briefly to Oak Ridge and then to Los Alamos. I arrived there, as it turns out, just two days before the test of the first atom bomb at Alamogordo. I can show you samples of the glass that were produced when the first atom bomb was exploded in Alamogordo on the sand of the desert. It’s sort of a glass, coming from the tremendous heat of the atom bomb.

Two methods had been used to try to develop an atom bomb. They were sort of the genius of [J. Robert] Oppenheimer, shown here together with Leslie Groves. I’d like to tell you a little bit about those two men, because they were quite impressive. Oppenheimer himself was an incredibly incredible scholar. He knew everything, it seemed like. He, for example, read Sanskrit. He was perhaps the second really great theoretical physicist in the United States after [Josiah Willard] Gibbs.

Furthermore, he had an amazing ability to get along well with people. He sort of held them in the palm of his hands, almost.  Most people, when they want to impress you, they’re getting excited and they speak louder and louder. Oppenheimer did precisely the opposite. If he wanted to make a point, he lowered his voice so that everybody would lean forward to be sure to hear what he was saying. In some way, Oppenheimer, at the end, was a fairly tragic figure, because his clearance was taken away, and I’ll talk about that a little bit later.

General Groves was entirely different kind of man. He was an engineer. He didn’t really know very much science. He was, however, amazing, in some regards, because he picked Oppenheimer. That’s incredible that he chose [him]. Incredible that he chose him, because Oppenheimer had several things against him. Security people were very much against having Oppenheimer as the director of Los Alamos.

To give you some idea of Groves: he was really a military man, and he thought he would treat scientists just like the military people. But little by little, he found out that wouldn’t work. I remember—which shows how immature I was in some way—a group of us in the Tech Area, where it was illegal to salute, because it was dangerous. You might be carrying radioactive material around or something. A group of us lined up in a line and marched right up to General Groves and did not salute. [Audience laughter] After the war, General Groves got his way. As soon as the Japanese surrendered, all of sudden, we had inspections and all the fol-de-rol of being in a real Army.

The two methods that were developed at Los Alamos for exploding the atom bomb. I’ll talk about now. The first is called gun-type. In it, a piece of non-critical uranium—that’s something that by itself will not explode—is driven by an explosive charge into an annulus of another piece, which is also non-critical. When the two come together, you produce a critical amount, and the thing will explode. This is, in fact, the mechanism and the material, which is uranium-235, that was used on Hiroshima.

Student 1: What was the last [inaudible]. 

Sheline: I think there’s nothing in between. That’s it’s [inaudible].

Okay. The second method, the one which I worked on at Los Alamos, is sometimes the snowball method, because it’s like squeezing a snowball. The idea is that you have a series of shaped charges around a spherical piece of plutonium or uranium. In fact, the one that was plutonium-239 was what was used. Whereas the sphere before explosion was not critical, it was very near critical. By squeezing it, making it smaller, you actually produced a critical mass and it will explode.

Now, I come to one of the parts of my talk which is especially difficult to tell you about. The decision had to be made on whether or not the drop the atom bomb on Hiroshima and Nagasaki. Certainly, some of the scientists at Los Alamos—I was among them—preferred that we try and to have a demonstration on a deserted island to show the Japanese the force of the atom bomb, in the hope that they would then surrender.

However, what I didn’t know—and I think most of my colleagues there didn’t know—is, at that time, there were only two or three atom bombs available. In some sense, what we were doing was a [inaudible]. Although others would be coming, at that exact time, there were very few atom bombs available. Truman, who was president by now—Roosevelt died of a heart attack—had to make the decision, and he made the decision to drop the bomb on Hiroshima.

The test of the snowball mechanism occurred July 16th, 1945. The Hiroshima bomb, the gun-type, was dropped on Hiroshima on August 6th, 1945. These are the people who flew the Enola Gay, about which there’s been a lot of controversy. This is the Enola Gay. There’s been this controversy at the Smithsonian Institute. 

About 125,000 people were killed at Hiroshima. Here is a picture of some of the devastation. The Japanese didn’t surrender right after Hiroshima. Three days later, the other bomb, the snowball mechanism—sometimes it’s called the Fat Man, and here it is—was dropped on Nagasaki.

It’s easy to rationalize: we saved lives by dropping these two bombs and killing 250,000 people. Because if we’d had to go from island to island and invade the homeland of Japan, it’s hard to say how many lives would have been lost.

Of course, we can’t know how soon the Japanese would have surrendered. I’ve talked to many different people, servicemen. Talked to somebody just today who say, “I wouldn’t be here if the bomb hadn’t been dropped.”

It’s difficult to know whether the United States was right or not. I certainly cannot fault Truman. He had all the facts. But I personally—and I know other scientists like me—will always carry a sense of guilt because of what happened.

Let me go on to tell you something about the [inaudible]. Of course, the atom bomb was not the end of things. The atom bomb became just the fuse to the hydrogen bomb. That work was done, developed essentially by Stan Ulam and by Edward Teller, shown here with Norris Bradbury, who took over at Los Alamos after Oppenheimer left.

I’ll tell you just a bit about Edward Teller. I got to know him very well when I consulted for the Chancellor of the University of California system. We were to give advice on the operation of Los Alamos and Livermore and some of the other laboratories.

Teller was an incredibly brilliant man. He had idea after idea. Just tossed them off like nothing. On the other hand, Enrico Fermi would knock them down just about as fast as they came out. [Audience laughter] Teller didn’t appreciate that very much, I can tell you that. But if you have only one good idea of maybe fifty or 100, that’s good enough. He was really brilliant.

On the other hand, I would say, he was obsessed with a fear of Russia. He was absolutely determined that we should build the hydrogen bomb. When Oppenheimer dragged his feet, Teller was tremendously upset. It was partly as a result of this that Teller testified in the security clearance hearings for Oppenheimer. Oppenheimer lost his security clearance and became a sort of tragic figure, a guy who was revered by most of American physicists. On the other hand, Teller, having testified against him, was sort of persona non grata. He was, and still is, I think, looked down upon by many American physicists.

What happens in the hydrogen bomb is—initially it was called a device. In fact, at Los Alamos, it was called the “Super” before it was called the hydrogen bomb. Initially, the idea was to fuse deuterium and tritium to make helium-4 and a neutron, and give off sort of unlimited amounts of energy.

In fact, we know that because you have to put together a critical amount, but you can’t that amount to begin with for an atom bomb, the size of an atom bomb is definitely limited by how much you can put together simultaneously that is not initially critical.

On the other hand, the hydrogen bomb is unlimited, in some sense, because once the atom bomb ignites it, any amount of fusible material can be set off. It turns out that shortly after the initial idea of using tritium and deuterium, hydrogen-3 and hydrogen-2, it was recognized that lithium-6 and deuteride was a much better fissionable material.

However, the fact that you can use unlimited explosive power with the hydrogen bomb leads to a new dilemma far beyond the realm of science. That’s what I want to finish talking about today. It is possible, or close to the realm of possibility, for man to commit global suicide with what is called the hydrogen, what is called the cobalt bomb or the hydrogen bomb. This is shown on the last transparency, and it is hypothetical. It’s never been built. It’s something, however, which is certainly within the range of imagination.

Let me tell you about it. The cobalt bomb begins with an atom bomb as a fuse, an explosion, something to heat up. You use, for example, three tons of tritium, two tons of deuterium, and you get a reaction: tritium plus deuterium; helium-4 plus neutrons. You get a ton of neutrons, and you start with three tons of tritium and two tons of deuterium.

Now, you surround this hydrogen bomb with a blanket of cobalt. Cobalt-59, you would need 59 tons, going with the simple equation, to react with the one ton of neutrons to give you 60 tons of cobalt-60. That cobalt-60 is enough, if spread equally over the surface of the earth, to kill everything—with the possible exception of some insects, particularly the cockroach, which is particularly capable of sustaining radiation. They live in reactors, and they do surprisingly well in very high fields of radiation.

Now, I have to give you some caveats about this cobalt bomb. First of all, it would tend to go into outer [space]. If you just shoot it off in the atmosphere, it would blow into outer space and most of the cobalt-60 would be dissipated in space. If you’re really going to use this effectively, you would have to shoot it off deep in a mountain, so it couldn’t blow completely into outer space. Secondly, of course, there’s always meteorology. Rain storms would make much more of the activity come down in some places than others. Wind direction, all of this would be important.

Perhaps we would only come to the verge of committing global suicide. But you must also recognize that this is not the only way we can commit global suicide. Bacteriological weapons might be easier, maybe even better. We are getting close to the time when we really could commit global suicide.

But you say to me, “No one would do this. Who would want to commit suicide? That’s absurd.” But think for a second about Hitler hiding under Berlin at the end of World War II. He was already committed, I think, to suicide. I believe that he would have taken a sort of perverse joy in taking everybody with him if he could have. He even made speeches to say that he would tear down Europe for a thousand years to come.

What, then, is the answer to this dilemma? We cannot guarantee that the human race will not produce other Hitlers. They almost certainly already exist in the five to six billion people on this earth. Fortunately, they don’t have the power which Hitler had.

In all honesty, I don’t really know the answer to this dilemma. It’s interesting, in the scientific realm, we can expect our students to climb on the backs of a Newton or an Einstein or a Dirac or a Schaefer and go on from there to greater heights in science. That is because science is a rational kind of structure. However, in the realm of ethics and morality, we cannot climb on the backs of a Jesus or a Mohammad or a Gandhi. We cannot be handed our morality on a silver platter, the way our greatest scientists have handed us their knowledge.

This, then, achieving the kind of morality that can allow our world to continue, is our greatest challenge. Thank you.

[Audience applause]

Dr. Hans Plendl: Should have any questions from the audience? Yes, sir?

Student 2: When you were working for the project, what did you know and when did you know it?

Sheline: Yes. That’s a good question. The question was, you were working on the project, what did you know and when did you know it?

When I came to Columbia University, I knew nothing. The way of security was to have each small project totally separate from every other one, so that nobody knew what the other people were doing. It was very difficult to find out what was going on.

However, I had talked with lots of other people, and there was considerable discussions of what was going on. We had some ideas. We weren’t really sure that they were right at all. In fact, some of them were wrong. However, the head of our group, a man by the name of Homer Priest, called us all together and said, “I’m not supposed to do this, but I’m going to tell you.”

Student 3: [Question about the FBI and clearance.]

Sheline: Clearance was absolutely necessary. Some of my neighbors in Toledo, Ohio, where I grew up, talked to my parents, asking what was going on, because several of them had been contacted about me. The FBI and CIA were certainly involved. [Inaudible].

Student 4: [Question about Klaus Fuchs.]

Sheline: Yes, I had seen Klaus Fuchs. I didn’t know him personally. He was a quite able scientist. Highly thought of. He fled to Britain before he came to the United States.

Student 5: You were at Los Alamos.

Sheline: Yes.

Student 5: [Inaudible].

Sheline: Yes.

Student 5: Well, what was the situation [inaudible].

Sheline: Well, they still attempted keep them compartmentalized until after the war. As a matter of fact, after the bomb went off at Alamogordo, this was kind of a security breach. I got this piece of fused sand. This is from the first atom bomb blast. It’s a sort of glass, which occurred because of tremendous heat from the atom bomb, sort of [inaudible].

Student 5: Is it still radioactive?

Sheline: Yes, it’s still somewhat radioactive, not dangerously so at all. Yes?

Student 6: At the time of the first test of the atom bomb, didn’t Oppenheimer and others have a contest as to whether or not it would spread across the world?

Sheline: Yes. I can tell you, I don’t know whether this is—I have to first say, I was not at the first atom bomb explosion. I was at Los Alamos, but not at the atom bomb explosion. I don’t know for sure what I’m telling is correct, but I know what people said.

It was said kind of in a joking way that Fermi—not Oppenheimer—but Fermi and Teller had a bet that whether or not the atom bomb would ignite the atmosphere. Fermi bet that it would not, and Teller bet that it would, and, of course, only Fermi could live.

Yes?

Student 7: Do you believe that a project of this scope could be conducted today?

Sheline: I think it probably could not be conducted as secretly today. People, of course, realized something very unusual was happening at Oak Ridge, where these tremendous amounts of material came into the building, the K-25 plant.