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 composure, 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.
It was a fitting departure for one of the two greatest minds that natural science has ever known. There had not been a scientist of that stature since Newton’s death in 1727. Perhaps to lesser and frailer mortals it brings Einstein nearer to common earth to know that in those last years he once lost his temper. Not about the profoundest problems of physics and philosophy; not about the possibilities of mass annihilation; but about something much closer to a personal quarrel.
He was very angry, abusively angry, when Max Born, one of his oldest and most cherished colleagues, said that he intended to return to Germany for his years of retirement. Einstein couldn’t understand or tolerate this. To go and live among those murderers who had slaughtered millions of ‘our people’!
For the only time traceable in all Einstein’s correspondence, his magnanimity, kindness, even his courtesy deserted him. He had once said that he had no ties at all, not to a nationality, a state, an institution, even a group of friends or family. He was a solitary and all he belonged to was the human race. In old age there was an exception, but one which was discernible much earlier. It is necessary to repeat he wasn’t a believing Jew. He had no God except perhaps Spinoza’s impersonal God of the cosmos: but in some sense deeper than reason he had come to belong to his people, that is the Jewish people.
Born was upset by the tone of those letters, since he revered Einstein above all men. Einstein would not relent. Nothing in this life, or in the space-time of the universe, would make him forget or forgive the ‘final solution’.
It was in his old humane spirit that he issued his warning about world peril, and went on working at his equations the day before he died. (He had an aneurysm, had known for years that death was imminent and thought nothing of it – what was mortality in this universe?)
Others, not so far above the battle as Einstein, accepted more passionately that he was right about the H-bomb. Science had made it possible for the human race to commit suicide. How wide this feeling of fatality spread, no one really knew. But it was there.