by C. P. Snow
It is a sad story. Probably the result didn’t make any real difference. Even if Bohr had prevailed, and there had been some attempt at international understanding, in practical terms everything would have gone on as it actually did in America, the Soviet Union, the United Kingdom, France, and in due course a good many other countries. There might have been a faint improvement in external civility, which is sometimes worth having. But the story remains a sad one, and something of a symbol.
Meanwhile the manufacture of the first bomb went on, the pace of sheer activity increasing. The Hitler war ended but there was no let-up. It was an illusion believed by many that there was a whole arsenal of bombs. That wasn’t true for a long time. There was an assembly on a tower, not an actual bomb, for the test – a plutonium device. Two bombs (one of each) which should be ready for use; one more plutonium bomb was in reserve. The rest consisted of threats.
By this time none of the scientists had doubts that the bomb would work: or at least no such doubt appeared in records or memoirs. Some political placemen, like the ineffable Leahy, added to their reputation for hard-bitten wisdom by continuing to regard the whole project as nonsense, a kind of long-haired hoax that wouldn’t produce anything more lethal than a popgun.
Some of the scientists, though, had a different worry. They were sure that the bombs would be ready for use: but what would they be used for? Not many people seemed to have answered the question. The bombs had been made as an insurance against the Nazis making them too and they hadn’t needed to think further than that. Now the Nazis were eliminated. A whisper spread that the American military were intending to use the bombs on Japan.
Some of the American scientists had relatives in the forces who would be fighting if there was an invasion of Japan. For them the ethical problem was simple: anything to get that war over. Just as the most charitable of Russians years later used to say, not lightly, that if they had possessed the bomb in early 1945, they would have dropped it on Berlin. They had lost too many men to have qualms. But most of the scientists were free to have such qualms. They hadn’t access to diplomatic intelligence, which would have increased their misgivings. Still, it was enough to know that here was the climactic feat of applied science: it just couldn’t be used for mass extermination without a thought. At the very least, there must be a demonstration. Warn the Japanese, drop a bomb in the sea. That would tell its own story. After that, consciences would be relatively clean.
Something like that was in fact proposed by Josef Franck, the leader of the Chicago group, another Nobel prize winner, a refugee from Göttingen and, like Born, another witness to the old German culture. He and half a dozen of his colleagues sent a statement to Washington. It had one vestige of a result. A small group of the Manhattan scientists were asked to give their opinion. This group consisted of Oppenheimer, Fermi, Ernest Lawrence, and the British Nobel prize winner A H Compton. They replied within a matter of days. Their opinions divided down the middle, two on each side. Oppenheimer and Fermi were in favour of dropping the bomb (actually the two bombs) without any preliminaries. Lawrence and Compton were against.
Probably nothing, or no representations from any man alive, could have stopped the bomb being used. As Einstein was to remark years later, there was a weird inevitability about it all.
The events that followed in July and August 1945 have often been described. The test at Alamogordo in the New Mexico desert went exactly according to expectation. If anything, the explosion was more powerful than predicted. It was one thing to have expectations, to believe in the certainties of reason: it was even more satisfactory to see them fulfilled as the most brilliant exhibition created by man. The scientists were jubilant, and they wouldn’t have been human if they hadn’t been. Fermi, with one of his Heath Robinson contrivances, was measuring blast by means of tin cans and pieces of paper. Someone more sardonic than the rest remarked that it was the most expensive dry run in scientific history.
The bombs were duly dropped. On 6 August Hiroshima was the target for the uranium-235 bomb; Nagasaki suffered the plutonium bomb three days later. Why was the second judged necessary? The question elicited comments, some cynical, some heart-wrung. There were utterances, in public and private, all over the physicists’ world. The scientists have learned sin, said Oppenheimer. That was too rhetorical for what they truly felt. Many of them were searching for some effective action. Mark Oliphant not only made his speech about the death of a beautiful subject, but also was demanding that England and his own Australia should make the bomb themselves. Any country without it was helpless from now on. Others were campaigning for international control, as Bohr had urged on Churchill in their grotesque meeting.
However, those thoughts of August 1945 weren’t to survive for very long. The future was to become not quite so apocalyptic. Physics hadn’t been killed, and the beautiful subject stayed beautiful, though in forms as yet unimaginable. While applied physics, and the technology born out of it, was not to have ended with the bomb, but scarcely to have begun.
8: Nuclear Fusion
WHEN the news of Hiroshima was first broadcast, a select assembly of German nuclear scientists (Heisenberg and Hahn amongst them) were in gentlemanly captivity in a Cambridgeshire country house. Their conversation was bugged. To begin with, they didn’t believe the BBC report. This wasn’t a fission bomb. It was some kind of bluff, designed to frighten the Japanese into making peace. After all, they, the Germans, hadn’t found a way of making such a bomb. How could the Anglo-Americans have done so?
The mystery was the exact opposite. Why hadn’t the Germans come nearer? The answer seems to be that, until late in the war, the German authorities, with whom decisions usually went much too high, often to Hitler himself, weren’t prepared to devote resources to projects which wouldn’t guarantee results within a couple of years. They wanted weapons for use next year, not in the dim future. Their engineering was still excellent, in many fields much better than that of the Anglo-Americans. They were producing the jet fighter, Me 262, by far the best fighter in the war, which didn’t come into service until too late. Similarly with their final type of submarine. But they didn’t expend any of that engineering skill on a nuclear bomb. That was too remote, and might as well be left to the scientists.
The scientists appear not to have had much access to high authority, or not much influence. Further, good as they were, as good as their counterparts in America, they didn’t show themselves as flexible and adaptable. Apparently, though it seems inexplicable, they had no equivalent of the Peierls-Frisch calculations about the practicality of the bomb (the Germans were thinking in terms much more gigantesque). The German scientists didn’t transform themselves into wartime engineers. They had no Fermi. If they had acquired him, it could have made a difference.
There gradually emerged a sweet romantic story, much to the credit of human nature, that the German scientists had deliberately held back. They wouldn’t accept the moral responsibility of giving such bombs to a monstrous regime. It would be an intolerable crime. Better to pretend that the bomb wasn’t feasible.
Well, it is a sweet story, but it happens to be utterly untrue. These were decent men: they were also dutiful men and, some of them, nationalistic Germans. Heisenberg had visited Bohr in occupied Copenhagen in 1941, and Bohr was certain that it was an attempt, not to inquire if Allied scientists had conscientious scruples, but whether they were setting about the job. From 1943 onwards, men as intelligent as Heisenberg knew that their country was fighting a desperate defensive war. If they lost, that was the end of Germany. Even under Nazi rule, Germany was Germany. In comparable circumstances, American, English, Russian scientists would have felt that the evils of the regime counted for nothing against the evils of absolute defeat. They would have gone to the limit to make the bomb.
Nothing is known in the West of whether the Soviets had started their own nuclear project before the end of the war. As with the Germans, they were fighting a desperate war, and may not have been able
to spare effort for longer-term enterprises. They certainly knew a good deal about what was happening in America. They had their legitimate sources of intelligence: and others, such as Klaus Fuchs, not so legitimate. When Stalin was told at Potsdam that the bomb was ready, it can’t have come as a surprise.
Whether they had started before or not, they threw immense energy into catching up. The only genuine secret, as someone said, was that the bomb had been made. It wasn’t hard, as Bohr and others had tried to impress upon the politicians years before, for another technological society to make it. Politicians, or some of them, still listened to General Groves and similar thinkers – it would take a generation for the Soviets to possess their own bomb. It took four years. That figure had been about the average of the scientists’ estimates.
The nuclear arms race was on. There was a sudden acceleration which made many thoughtful men lose what remained of their wits. It became likely that a different kind of nuclear bomb, many times more powerful than the fission bomb, could be developed. This was the hydrogen, or fusion, bomb.
In the Hiroshima and Nagasaki bombs, the heaviest of atomic nuclei – uranium and plutonium – broke up into smaller, more stable nuclei. The most stable of all nuclei, in fact, are intermediate-weight ones, like iron, which has 56 nuclear particles (26 protons and 30 neutrons). This means that one can take a different route to nuclear energy: join together – ‘fuse’ – the very lightest elements of all to make slightly heavier nuclei, and thereby generate energy. Before the war, astrophysicists had calculated that the sun – and most other stars – makes energy this way. At the sun’s core, hydrogen nuclei (protons) get together in fours to make helium nuclei. The energy liberated is sunshine.
But it is also possible to release the energy of hydrogen fusion explosively, and it is far more efficient than the fission of uranium or plutonium. Should a hydrogen bomb be made, it would be a thousand times more powerful than the fission bomb. Such a bomb could annihilate the largest of cities, London, Chicago, Moscow. It would be the ultimate weapon.
Could it be made? Should it be made?
About the answer to the first question, most of the leaders hadn’t much doubt. The history of the fission bomb had made them technologically confident. What was possible in theory, had proved to be workable in practice. At first inspection, there didn’t look to be quite the number of critical problems that they had had to grapple with between 1941 and 1945. (In actual fact, there turned out to be some of extreme difficulty.)
As for the second question – should the bomb be made? – everyone knew what the answer was going to be. This was a weapon of war, different in kind, more lethal by a thousand times than any in existence. Has any advance, even a tiny one, in a weapon of war ever been abnegated in the whole of human history? Because of the demands of human conscience, that is. Many such advances have been missed because of miscalculation or stupidity, but that is a somewhat less interesting matter.
Still, though the issue was a foregone conclusion, there were scruples, doubts, hesitations, such as there hadn’t been about the first nuclear bomb. Then – so it had seemed – it could mean immediate life or death. This time the dangers were harder to foresee and in any case were much longer-term. Oppenheimer was in a state of moral anxiety. He lived closer to his own experience than most decision-makers, and he was in contact with what others thought about him and what he thought about himself. He would have liked a good reason, technical or military, why the hydrogen bomb shouldn’t be proceeded with. He didn’t find one. He was for once unable to explain his doubts with precision. Previously, though he was too sensitive for an ideal man of action, he had been able to command his own will. Now, it seems that he couldn’t.
In Moscow there was a dilemma which had some family resemblances. Kapitsa decided that he could not work on the hydrogen bomb. The American and Soviet discussions and plans were proceeding almost simultaneously. Kapitsa’s reasons for wanting to contract out were not the same as Oppenheimer’s. Kapitsa was a civilized and enlightened man, a descendant of the professional (not landed) Russian upper class, for so long in Tsarist times the guardians of liberal hopes. His father and paternal grandfather had both been distinguished generals in the Tsarist army, but that didn’t prevent them sharing those hopes. On the other hand, a military family, however enlightened, is impelled to put the safety of the country first and foremost. Certainly Stalin thought so, and never, and rightly, had any suspicions about Kapitsa’s fundamental loyalty – which was fortunate for the hundred or more scientists, mainly Jewish, whom Kapitsa saved in the worst days of the purges, from 1937 to 1940, which Russians call the Yezhovshchina. Kapitsa took many risks, but, as he’d had with Rutherford, he could have some influence with Stalin. He was later known to say that those two were the only men who ever loved him.
It is unlikely that Kapitsa’s main motive in refusing to collaborate on the hydrogen bomb was, in the narrow sense, humanitarian. He was a much tougher-minded man than Oppenheimer, and it is far more probable that he would have argued that if one superpower possessed this super-bomb, the other had better have it too. He always had a deep, almost sensual, Russian patriotism. It would be wrong, perhaps, to eliminate all thoughts of revulsion at mass slaughter on a world scale brought about by scientific means. A good many scientists felt that revulsion, at the time, and since. Kapitsa seems, however, to have had a more professional reason for absenting himself. His institute, he himself, would be important figures in the H-bomb programme. The officials – presumably the technical officers at the Ministry of Defence – proposed to tell him what to do. That he couldn’t and wouldn’t take. He knew that on this kind of job he was as valuable as any man in the Soviet Union. He wanted his own way.
He remained obdurate. All that happened to him was a mild form of house-arrest. Since his house was a hundred yards across a kind of college court from his own institute, that didn’t cut him off from his own research. Scientific publications flowed in as usual. He brooded in a classical Russian fashion. As soon as the house-arrest was called off, all acted as though it hadn’t been. He received a Nobel prize twenty years later, in his eighties.
Large teams in the United States and the Soviet Union busied themselves with the hydrogen bomb. Some of the participants in the fission bomb programme were in this project also, such as the still young John Wheeler. Not much is known of the Soviet scientists actively involved, with one exception.
In both countries two men who became, in rather different ways, world figures, had commanding responsibility for the hydrogen bomb. Both had great technical (scientific and technological) daring and exceptionally strong wills. In America Edward Teller, in the popular view, later became the chief scientific spokesman of the conservative right, and was known, rather more justly, as the father of the H-bomb. In the Soviet Union a much younger man, still in his twenties when he achieved his major work, fulfilled something close to the same function. The details are not yet known, but his achievement may have been similar to Teller’s. The young man was Andrei Sakharov, whom more worldly Russians described as a pure soul rather like Dirac, and who in middle age spoke in Moscow as the most intellectually creditable of dissidents.
It doesn’t need saying that the H-bomb was duly made. From start to finish, it took the American scientists just under four years and the Soviet scientists a few months longer. Once again, this was something like what cool-minded observers had reckoned on.
The H-bomb was the last dramatic contribution of high science to the world’s military situation. In the 1950s it brought a sense of doom to many men of good sense and good will. It did so to Einstein, who died in 1956. He spent some of his final energies warning humanity about its dangers. He didn’t do that sentimentally, for, as has been said, he was the least sentimental of men. His heart does not bleed, his eyes do not weep, said someone who idolized him. He took it as a final duty, having ceased to expect much sensible behaviour from humankind. He faced his own death with majestic and impersonal compos
ure, saying that on this earth he had done his job. Few men could have said that with more justification.
There was one job, however, that he hadn’t finished. He hadn’t discovered the ‘unified field theory’, the search for which had occupied the second half of his life.
After his brilliant explanation of gravitation in his General Theory of Relativity back in 1915, Einstein had spent the rest of his life in an attempt to formulate a theory which would cover all the forces of nature at once. At first his unified field theory needed to combine gravitation and electromagnetism under the same set of equations. By the 1930s there was the nuclear force to include. In the 1950s, the physicists knew there were two types of nuclear force, very different in character and strength. A unified theory must cope with four forces.
For all his efforts, Einstein had no success. Having little truck with quantum mechanics, he attempted to model the other forces along the lines of General Relativity. They wouldn’t go. In recent years, physicists actually have had some success in combining the theories of the two nuclear forces and electromagnetism. They have succeeded where Einstein failed because they have taken the road of quantum mechanics, not relativity. Einstein’s tremendous instinct for physics had sadly gone astray, and led him up a blind alley for the last forty years of his life. When he died, he also hadn’t concluded the decades-long debate with Bohr about chance and causality. He hadn’t prevailed, though he was still immovable, certain that he was right. No one else was. But nothing would persuade Einstein that God played at dice.