If there was a single moment when an atomic bomb moved out of the realm of theory and became a practical option, then it occurred one night in early 1940, in Birmingham, England. The Blitz was in full spate, there were blackouts every night, when no lights were allowed, and at times Otto Frisch and Rudolf Peierls must have wondered whether they had made the right decision in emigrating to Britain.
Frisch was Lise Meitner’s nephew, and while she had gone into exile in Sweden in 1938, after the Anschluss, he had remained in Copenhagen with Niels Bohr. As war approached, Frisch grew more and more apprehensive. Should the Nazis invade Denmark, he might well be sent to the camps, however valuable he was as a scientist. Frisch was also an accomplished pianist, and his chief consolation was in being able to play. But then, in the summer of 1939, Mark Oliphant, joint inventor of the cavity magnetometer, who by now had become professor of physics at Birmingham, invited Frisch to Britain, ostensibly for discussions about physics. (After Rutherford’s death in 1937 at the age of fifty-six, from an infection following an operation, many from the Cavendish team had dispersed.) Frisch packed a couple of bags, as one would do for a weekend away. Once in England, however, Oliphant made it clear to Frisch he could stay if he wished; the professor had made no elaborate plans, but he could read the situation as well as anyone, and he realised that physical safety was what counted above all else. While Frisch was in Birmingham, war was declared, so he just stayed. All his possessions, including his beloved piano, were lost.1
Peierls was already in Birmingham, and had been for some time. A wealthy Berliner, he was one of the many brilliant physicists who had trained with Arnold Sommerfeld in Munich. Peierls had been in Britain in 1933, in Cambridge on a Rockefeller fellowship, when the purge of the German universities had begun. He could afford to stay away, so he did. He would become a naturalised citizen in Britain in February 1940, but for five months, from 3 September 1939 onward, he and Frisch were technically enemy aliens. They got round this ‘inconvenience’ in their conversations with Oliphant by pretending that they were only discussing theoretical problems.2
Until Frisch joined Peierls in Birmingham, the chief argument against an atomic bomb had been the amount of uranium needed to ‘go critical,’ start a chain reaction and cause an explosion. Estimates had varied hugely, from thirteen to forty-four tons and even to a hundred tons. Had this been true, it would have made the bomb far too heavy to be transported by aircraft and in any case would have taken as long as six years to assemble, by which time the war would surely have been long over. It was Frisch and Peierls, walking through the blacked-out streets of Birmingham, who first grasped that the previous calculations had been wildly inaccurate.3 Frisch worked out that, in fact, not much more than a kilogram of material was needed. Peierls’s reckoning confirmed how explosive the bomb was: this meant calculating the available time before the expanding material separated enough to stop the chain reaction proceeding. The figure Peierls came up with was about four millionths of a second, during which there would be eighty neutron generations (i.e., I would produce 2 would produce 4→8→16→32 … and so on). Peierls worked out that eighty generations would give temperatures as hot as the interior of the sun and ‘pressures greater than the centre of the earth where iron flows as a liquid.’4 A kilogram of uranium, which is a heavy metal, is about the size of a golf ball – surprisingly little. Frisch and Peierls rechecked their calculations, and did them again, with the same results. And so, as rare as U235 is in nature (in the proportions 1 : 139 of U238), they dared to hope that enough material might be separated out – for a bomb and a trial bomb – in a matter of months rather than years. They took their calculations to Oliphant. He, like them, recognised immediately that a threshold had been crossed. He had them prepare a report – just three pages – and took it personally to Henry Tizard in London.5 Oliphant’s foresight, in offering sanctuary to Frisch, had been repaid more quickly than he could ever have imagined.
Since 1932, when James Chadwick identified the neutron, atomic physics had been primarily devoted to obtaining two things: a deeper understanding of radioactivity, and a clearer picture of the structure of the atomic nucleus. In 1933 the Joliot-Curies, in France, had finally produced important work that won them the Nobel Prize. By bombarding medium-weight elements with alpha particles from polonium, they had found a way of making matter artificially radioactive. In other words, they could now transmute elements into other elements almost at will. As Rutherford had foreseen, the crucial particle here was the neutron, which interacted with the nucleus, forcing it to give up some of its energy in radioactive decay.
Also in 1933 the Italian physicist Enrico Fermi had burst on the scene with his theory of beta decay (despite Nature turning down one of his papers).6 This too related to the way the nucleus gave up energy in the form of electrons, and it was in this theory that Fermi introduced the idea of the ‘weak interaction.’ This was a new type of force, bringing the number of basic forces known in nature to four: gravity and electromagnetism, operating at great distances, and the strong and weak forces, operating at the subatomic level. Although theoretical, Fermi’s paper was based on extensive research, which led him to show that although lighter elements, when bombarded, were transmuted to still lighter elements by the emission of either a proton or an alpha particle, heavier elements acted in the opposite way. That is to say, their stronger electrical barriers captured the incoming neutron, making them heavier. However, being now unstable, they decayed to an element with one more unit of atomic number. This raised a fascinating possibility. Uranium was the heaviest element known in nature, the top of the periodic table, with an atomic number of 92. If it was bombarded with neutrons and captured one, it should produce a heavier isotope: U238 should become U239. This should then decay to an element that was entirely new, never before seen on earth, with the atomic number 93.7
It would take a while to produce what would be called ‘transuranic’ elements, but when they did arrive, Fermi was awarded the 1938 Nobel Prize. The day that Fermi heard he had been awarded the ultimate honour was exciting in more ways than one. First there was a telephone call early in the morning; it was the local operator, to say they had been told to expect a call that evening at six o’clock, from Stockholm. Suspecting he had won the coveted award, Fermi and his family spent the day barely able to concentrate, and when the phone rang promptly at six, Fermi rushed to answer it. But it wasn’t Stockholm; it was a friend, asking them what they thought of the news.8 The Fermis had been so anxious about the phone call that they had forgotten to switch on the radio. Now they did. A friend later described what they heard: ‘Hard, emphatic, pitiless, the commentator’s voice read the … set of racial laws. The laws issued that day limited the activities and the civil status of the Jews [in Italy]. Their children were excluded from the public schools. Jewish teachers were dismissed. Jewish lawyers, physicians and other professionals could practise for Jewish clients only. Many Jewish firms were dissolved…. Jews were to be deprived of full citizenship rights, and their passports would be withdrawn.’9
Laura Fermi was Jewish.
That was not the only news. The evening before, in Germany itself, anti-Semitism had boiled over: mobs had torched synagogues across the country, pulled Jewish families into the streets, and beaten them. Jewish businesses and stores had been destroyed in their thousands, and so much glass had been shattered that the evening became infamous as Kristallnacht.
Eventually the call from Stockholm came through. Enrico had been awarded the Nobel Prize, ‘for your discovery of new radioactive substances belonging to the entire race of elements and for the discovery you made in the course of this work of the selective power of slow neutrons.’ Was that reference fortuitous? Or was it Swedish irony?
Until that moment, although some physicists talked about ‘nuclear energy,’ most of them didn’t really think it would ever happen. Physics was endlessly fascinating, but as a fundamental explanation of nature rather than anything else. Ernest Rutherford gave a public lecture in 1933 in which he specifically said that, exciting as the recent discoveries were, ‘the world was not to expect practical application, nothing like a new source of energy, such as once had been hoped for from the forces in the atom.’10
But in Berlin Otto Hahn spotted something available to any physicist but missed. The more common isotope of uranium, U238, is made up of 92 protons and 146 neutrons in its nucleus. If neutron bombardment were to create new, transuranic elements, they would have not only different weights but different chemical properties.11 He therefore set out to look for these new properties, always keeping in mind that if the neutrons were not being captured, but were chipping particles out of the nucleus, he ought to find radium. A uranium atom that lost two alpha particles (helium nuclei, atomic weight four for each) would become radium, R230. He didn’t find radium, and he didn’t find any new elements, either. What he did find, time and again when he repeated the experiments, was barium. Barium was much lighter: 56 protons and 82 neutrons, giving a total of 138, well below uranium’s 238. It made no sense. Puzzled, Hahn shared his results with Lise Meitner. Hahn and Meitner had always been very close, and he had helped protect her throughout the 1930s, because she was Jewish. She was kept employed because, technically speaking, she was Austrian, and therefore, technically speaking, the racial laws didn’t apply to her. After the Anschluss, however, in March 1938, when Austria became part of Germany, Meitner could no longer be protected, and she was forced to escape to Göteborg in Sweden. Hahn wrote to her just before Christmas 1938 describing his unusual results.12
As luck would have it, Meitner was visited that Christmas by her nephew Otto Frisch, then with Bohr in Copenhagen. The pair were very pleased to see each other – both were in exile – and they went lang-laufing in the nearby woods, which were covered in snow. Meitner told her nephew about Hahn’s letter, and they turned the barium problem over in their minds as they walked between the trees.13 They began to consider radical explanations for Hahn’s puzzling observation, in particular a theory of Bohr’s that the nucleus of an atom was like a drop of water, which is held together by the attraction that the molecules have for each other, just as the nucleus is held together by the nuclear force of its constituents. Until then, as mentioned earlier, physicists had considered that when the nucleus was bombarded, it was so stable that at most the odd particle could be chipped off.14 Now, huddled on a fallen tree in the Göteborg woods, Meitner and Frisch began to wonder whether the nucleus of uranium was like a drop of water in other ways, too.15 In particular they allowed the possibility that instead of being chipped away at by neutrons, a nucleus could in certain circumstances be cleaved in two. They had been in the woods, skiing and talking, for three hours. They were cold. Nonetheless, they did the calculations there and then before turning for home. What the arithmetic showed was that if the uranium atom did split, as they thought it might, it could produce barium (56 protons) and krypton (36) – 56+36=92. They were right, and when Frisch told Bohr, he saw it straight away. ‘Oh, what idiots we have all been,’ he cried. ‘This is just as it must be.’16 But that wasn’t all. As the news sank in around the world, people realised that, as the nucleus split apart, it released energy, as heat. If that energy was in the form of neutrons, and in sufficient quantity, then a chain reaction, and a bomb, might indeed be possible. Possible, but not easy. Uranium is very stable, with a half-life of 4.5 billion years; as Richard Rorty dryly remarks, if it was apt to give off energy that sparked chain reactions, few physics labs would have been around to tell the tale. It was Bohr who grasped the essential truth – that U238, the common isotope, was stable, but U235, the much less common form, was susceptible to nuclear fission (the brand-new term for what Hahn had observed and Meitner and Frisch had been the first to understand). Bring two quantities of U235 together to form a critical mass, and you had a bomb. But how much U235 was needed?
The pitiful irony of this predicament was that it was still only early 1939. Hitler’s aggression was growing, sensible people could see war coming, but the world was, technically, still at peace. The Hahn/Meitner/Frisch results were published openly in Nature, and thus read by physicists in Nazi Germany, in Soviet Russia, and in Japan, as well as in Britain, France, Italy, and the United States.17 Three problems now faced the physicists. How likely was a chain reaction? This could be judged only by finding out what energy was given off when fission occurred. How could U235 be separated from U238? And how long would it take? This third question involved the biggest drama. For even after war broke out in Europe, in September 1939, and the race for the bomb took on a sharper urgency, America, with the greatest resources, and now the home of many of the exiles, was a nonbelligerent. How could she be persuaded to act? In the summer of 1939 a handful of British physicists recommended that the government acquire the uranium in the Belgian Congo, if only to stop others.18 In America the three Hungarian refugees Leo Szilard, Eugene Wigner, and Edward Teller had the same idea and went to see Einstein, who knew the queen of Belgium, to ask her to set the ball rolling.19 In the end they decided to approach Roosevelt instead, judging that Einstein was so famous, he would be listened to.20 However, an intermediary was used, who took six weeks to get in to see the president. Even then, nothing happened. It was only after Frisch and Peierl’s calculations, and the three-page paper they wrote as a result, that movement began. By that stage the Joliot-Curies had produced another vital paper – showing that each bombardment of a U235 atom released, on average, 3.5 neutrons. That was nearly twice what Peierls had originally thought.21
The Frisch-Peierls memorandum was considered by a small subcommittee brought into being by Henry Tizard, which met for the first time in the offices of the Royal Society in April 1940. This committee came to the conclusion that the chances of making a bomb in time to have an impact on the war were good, and from then on the development of an atomic bomb became British policy. The job of persuading the Americans to join in fell to Mark Oliphant, Frisch and Peierls’s professor at Birmingham. Strapped by war, Britain did not have the funds for such a project, and any location, however secret, might be bombed.22 In America, a ‘Uranium Committee’ had been established, whose chairman was Vannevar Bush, a dual-doctorate engineer from MIT. Oliphant and John Cockroft travelled to America and persuaded Bush to convey some of the urgency they felt to Roosevelt. Roosevelt would not commit the United States to build a bomb, but he did agree to explore whether a bomb could be built. Without informing Congress, he found the necessary money ‘from a special source available for such an unusual purpose.’23
*
While Bush set to work to check on the British findings, Niels Bohr in Copenhagen received a visit from his former pupil, the creator of the Uncertainty Principle, Werner Heisenberg. Denmark had been invaded in April 1940. Bohr had refused a guarantee by the American embassy of safe passage to the United States and instead did what he could to protect more junior scholars who were Jewish. After much talk, Bohr and Heisenberg went for a walk through the brewery district of Copenhagen, near the Carlsberg factories. Heisenberg was one of those in charge of the German bomb project in Leipzig, and on that walk he raised the prospect of the military applications of atomic energy.24 He knew that Bohr had just been in America, and Bohr knew that he knew. At the meeting Heisenberg also passed to Bohr a diagram of the reactor he was planning to build – and this is what makes the meeting so puzzling and dramatic in retrospect. Was Heisenberg letting Bohr know how far the Germans had got, because he hated the Nazis? Or was he, as Bohr subsequently felt, using the diagram as a lure, to get Bohr to talk, so he would tell Heisenberg how far America and Britain had progressed? The real reason for this encounter has never been established, though its drama has not diminished as the years have passed.25
The National Academy of Sciences report, produced as a result of Bush’s October conversation with the president, was ready in a matter of weeks and was considered at a meeting chaired by Bush in Washington on Saturday, 6 December 1941. The report concluded that a bomb was possible and should be pursued. By this stage, American scientists had managed to produce two ‘transuranic’ elements, called neptunium and plutonium (because they were the next heavenly bodies beyond Uranus in the night sky), and which were by definition unstable. Plutonium in particular looked promising as an alternative source of chain-reaction neutrons to U235. Bush’s committee also decided which outfits in America would pursue the different methods of isotope separation – electromagnetic or by centrifuge. Once that was settled, the meeting broke up around lunchtime, the various participants agreeing to meet again in two weeks. The very next morning the Japanese attacked Pearl Harbor, and America, like Britain, was now at war. As Richard Rhodes put it, the lack of urgency in the United States was no longer a problem.26
The early months of 1942 were spent trying to calculate which method of U235 separation would work best, and in the summer a special study session of theoretical physicists, now known as the Manhattan Project, was called at Berkeley. The results of the deliberations showed that much more uranium would be needed than previous calculations had suggested, but that the bomb would also be far more powerful. Bush realised that university physics departments in big cities were no longer enough. A secret, isolated location, dedicated to the manufacture of an actual bomb, was needed.
When Colonel Leslie Groves, commander of the Corps of Engineers, was offered the job of finding the site, he was standing in a corridor of the House of Representatives Office Building in Washington, D.C. He exploded. The job offer meant staying in Washington, there was a war on, he’d only ever had ‘desk’ commands, and he wanted some foreign travel.27 When he found that as part of the package he was to be promoted to brigadier, his attitude started to change. He quickly saw that if a bomb was produced, and it did decide the war, here was a chance for him to play a far more important role than in any assignment overseas. Accepting the challenge, he immediately went off on a tour of the project’s laboratories. When he returned to Washington, he singled out Major John Dudley as the man to find what was at first called Site Y. Dudley’s instructions were very specific: the site had to accommodate 265 people; it should be west of the Mississippi, and at least 200 miles from the Mexican or Canadian border; it should have some buildings already, and be in a natural bowl. Dudley came up with, first, Oak City, Utah. Too many people needed evicting. Then he produced Jemez Spring, New Mexico, but its canyon was too confining. Farther up the canyon, however, on the top of the mesa, was a boys’ school on a piece of land that looked ideal. It was called Los Alamos.28
As the first moves to convert Los Alamos were being made, Enrico Fermi was taking the initial step toward the nuclear age in a disused squash court in Chicago (he had emigrated in 1938). By now, no one had any doubt that a bomb could be made, but it was still necessary to confirm Leo Szilard’s original idea of a nuclear chain reaction. Throughout November 1942, therefore, Fermi assembled what he called a ‘pile’ in the squash court. This consisted of six tons of uranium, fifty tons of uranium oxide, and four hundred tons of graphite blocks. The material was built up in an approximate sphere shape in fifty-seven layers and in all was about twenty-four feet wide and nearly as high. This virtually filled the squash court, and Fermi and his colleagues had to use the viewing gallery as their office.
The day of the experiment, 2 December, was bitterly cold, below zero.29 That morning the first news had been received about 2 million Jews who had perished in Europe, with millions more in danger. Fermi and his colleagues gathered in the gallery of the squash court, wearing their grey lab coats, ‘now black with graphite.’30 The gallery was filled with machines to measure the neutron emission and devices to drop safety rods into the pile in case of emergency (these rods would rapidly absorb neutrons and kill the reactions). The crucial part of the experiment began around ten as, one by one, the cadmium absorption rods were pulled out, six inches at a time. With each movement, the clicking of the neutron records increased and then levelled off, in sync and exactly on cue. This went on all through the morning and early afternoon, with a short break for lunch. Just after a quarter to four Fermi ordered the rods pulled out enough for the pile to go critical. This time the clicks on the neutron counter did not level off but rose in pitch to a roar, at which point Fermi switched to a chart recorder. Even then they had to keep changing the scale of the recorder, to accommodate the increasing intensity of the neutrons. At 3:53 P.M., Fermi ordered the rods put back in: the pile had been self-sustaining for more than four minutes. He raised his hand and said, ‘The pile has gone critical.’31
Intellectually, the central job of Los Alamos was to work on three processes designed to produce enough fissile material for a bomb.32 Two of these concerned uranium, one plutonium. The first uranium method was known as gaseous diffusion. Metal uranium reacts with fluorine to produce a gas, uranium hexafluoride. This is composed of two kinds of molecule, one with U238 and another with U235. The heavier molecule, U238, is slightly slower than its half-sister, so when it is passed through a filter, U235 tends to go first, and gas on the far side of the filter is richer in that isotope. When the process is repeated (several thousand times), the mixture is even richer; repeat it often enough, and the 90 percent level the Los Alamos people needed is obtained. It was an arduous process, but it worked. The other method involved stripping uranium atoms of their electrons in a vacuum and then giving them an electrical charge that made them susceptible to outside fields. These were then passed in a beam that curved within an electrical field so that the heavy isotope would take a wider course than the lighter form, and become separated. In plutonium production, the more common isotope, U238, was bombarded with neutrons, to create a new, transuranic element, plutonium-239, which did indeed prove fissile, as the theoreticians had predicted.33
At its height, 50,000 people were employed at Los Alamos on the Manhattan Project, and it was costing $2 billion a year, the largest research project in history.34 The aim was to produce one uranium and one plutonium bomb by late summer 1945.
In early 1943 Niels Bohr received a visit from a captain in the Danish army. They took tea and then retired to Bohr’s greenhouse, which they thought more secure. The captain said he had a message from the British via the underground, to say that Bohr would shortly receive some keys. Minute holes had been drilled in these keys, in which had been hidden a microdot, and the holes then filled in with fresh metal. He could find the microdot by slowly filing the keys at a certain point: ‘The message can then be extracted or floated out on to a microslide.’35 The captain offered the army’s help with the technical parts, and when the keys arrived, the message was from James Chadwick, inviting Bohr to England to work ‘on scientific matters.’ Bohr guessed what that meant, but as a patriot he didn’t immediately take up the offer. The Danes had managed to do a deal with the Nazis, so that in return for providing the Reich with food, Danish Jews would go unmolested. Though the arrangement worked for a while, strikes and sabotage were growing, especially after the German surrender at Stalingrad, when many people sensed that the course of the war was decisively changing. Finally, sabotage became so bad in Denmark that on 29 August 1943 the Nazis reoccupied the country, immediately arresting certain prominent Jews. Bohr was warned that he was on the list of those to be arrested, and at the end of September, with the help of the underground, he escaped, taking a small boat through the minefields of the Öresund and flying from Sweden to Scotland. He soon moved on from Britain to Los Alamos. There, although he took an interest in technical matters and made suggestions, his very presence was what mattered, giving the younger scientists a boost: he was a symbol for those scientists who felt that the weapon they were building was so terrible that all attempts should be made to avoid using it; that the enemy should be shown what it was capable of and given the chance to surrender. There were those who went further, who said that the technical information should be shared, that the moral authority this would bring would ensure there would never be an arms race. A plan was therefore mounted for Bohr to see Roosevelt to put forward this view. Bohr got as far as Felix Frankfurter, the president’s aide, who spent an hour and a half discussing the matter with Roosevelt. Bohr was told that the president was sympathetic but wanted the Dane to see Churchill first. So Bohr recrossed the Atlantic, where the British prime minister kept him waiting for several weeks. When they finally did meet, it was a disaster. Churchill cut short the meeting and in effect told Bohr to stop meddling in politics. Bohr said later that Churchill treated him like a schoolboy.36
Churchill was understandably worried (and he was frantically planning the Normandy invasions at the time). How could they know that the Germans, or the Japanese, or the Russians were not ahead of them? With the benefit of hindsight, no one was anywhere near the Allies on this matter.37 In Germany, Fritz Houtermans had concentrated since about 1939 on making element 94, and the Germans – in the ‘U-PROJECT,’ as it was called – had thus neglected isotope separation. Bohr had been given that diagram of a heavy-water reactor and, drawing their own conclusions, the British had bombed the Vemork factory in Norway, the only establishment that manufactured such a product.38 But that had been rebuilt. Fresh attempts to blow it up were unsuccessful, and so a different plan was called for when, via the underground, it was learned that the heavy water was to be transferred to Germany in late February 1944. According to intelligence, the water was to be taken by train to Tinnsjö, then across the sea by ferry. On the twentieth of the month, a team of Norwegian commandos blew up the ferry, the Hydro, with the loss of twenty-six of the fifty-three people on board. At the same time, thirty-nine drums containing 162 gallons of heavy water went to the bottom of the sea. The Germans later conceded that ‘the main factor in our failure to achieve a self-sustaining atomic reactor before the war ended’ was due to their inability to increase their stocks of heavy water, thanks to the attacks on Vemork and the Hydro.39 This was almost certainly the most significant of the many underground acts of sabotage during the war.
The Japanese never really got to grips with the problem. Their scientists had looked at the possibility, but the special naval committee set up to oversee the research had concluded that a bomb would need a hundred tons of uranium, half the Japanese output of copper and, most daunting of all, consume 10 percent of the county’s electricity supply. The physicists turned their attention instead to the development of radar. The Russians were more canny. Two of their scientists had published a paper in Physical Review in June 1940, making certain new observations about uranium.40 This paper brought no response from American physicists, the Russians thus concluding (and maybe this was the real point of their paper) that the lack of a follow-through implied that the Western Allies were already embarked on their own bomb project, which was secret. The Russians also noticed what the Germans and the Japanese must have noticed as well, that the famous physicists of the West were no longer submitting original papers to the scientific journals; obviously they were busy doing something else. In 1939, therefore, the Russians started looking hard at a bomb, though work was stopped after Hitler invaded (again radar research and mine detection occupied the physicists, while the labs and materials were moved east, for safety). After Stalingrad, the program was resuscitated, and scientists were recalled from forward units. What was called ‘Laboratory Number Two,’ located in a derelict farm on the Moscow River, was the Russian equivalent of Los Alamos. But the lab only ever housed about twenty-five scientists and conducted mainly theoretical work regarding the chain reaction and isotope separation. The Russians were on the right lines, but years behind – for the time being.41
On 12 April 1945 President Roosevelt died of a massive cerebral haemorrhage. Within twenty-four hours his successor, Harry Truman, had been told about the atomic bomb.42 Inside a month, on 8 May, the war in Europe was at an end. But the Japanese hung on, and Truman, a newcomer to office, was faced with the prospect of being the man to issue the instruction to use the awesome weapon. By V-E Day, the target researchers for the atomic bombs had selected Hiroshima and Nagasaki, the delivery system had been perfected, the crews chosen, and the aeronautical procedure for actually dropping the mechanism tried out and improved. Critical amounts of plutonium and uranium became available after 31 May, and a test explosion was set for 05.50 hours on 16 July in the desert at Alamogordo, near the Rio Grande, the border with Mexico, in an area known locally as Jornada del Muerto, ‘the journey of death’.43
The test explosion went exactly according to plan. Robert Oppenheimer, the scientific director of Los Alamos, watched with his brother Frank as the clouds turned ‘brilliant purple’ and the echo of the explosion went on, and on, and on.44 The scientists were still split among themselves as to whether the Russians should be told, whether the Japanese should be warned, and whether the first bomb should be dropped in the sea nearby. In the end total secrecy was maintained, one important reason for doing so being the fear that the Japanese might move thousands of captured American servicemen into any potential target area as a deterrent.45
The U235 bomb was dropped on Hiroshima shortly before 9:00 A.M. local time, on 6 August. In the time it took for the bomb to fall, the Enola Gay, the plane it had been carried in, was eleven and a half miles away.46 Even so, the light of the explosion filled the cockpit, and the aircraft’s frame ‘crackled and crinkled’ with the blast.47 The plutonium version fell on Nagasaki three days later. Six days after that the emperor announced Japan’s surrender. In that sense, the bombs worked.
The world reacted with relief that the war was over and with horror at the means used to achieve that result. It was the end of one era and the beginning of another, and for once there was no exaggeration in those words. In physics it was a terrible culmination of the greatest intellectual adventure in what has traditionally been called ‘the beautiful science.’ But a culmination is just that: physics would never again be quite so heroic, but it wasn’t over.
Four long years of fighting the Japanese had given the rest of the world, especially the Americans, an abiding reason for being interested in the enemy, who – with their kamikaze pilots, their seemingly gratuitous and baffling cruelty, and their unswerving devotion to the emperor – seemed so different from Westerners. By 1944 many of these differences had become obvious, so much so that it was felt important in the military hierarchy in America to commission a study of the Japanese in order fully to understand what the nation was – and was not – capable of, how it might react and behave in certain circumstances. (In particular, of course – though no one was allowed to say this – the military authorities wanted to know how Japan would behave when faced with an atomic bomb, should one be prepared. By then it was already clear that many Japanese soldiers and units fought to the bitter end, even against overwhelming odds, rather than surrender, as Allied or German troops would do in similar circumstances. Would the Japanese surrender in the face of one or more atomic bombs? If they didn’t, how many were the Allies prepared to explode to bring about surrender? How many was it safe to explode?)
In June 1944 the anthropologist Ruth Benedict, who had spent the previous months in the Foreign Morale Division of the Office of War Information, was given the task of exploring Japanese culture and psychology.48 She was known for her fieldwork, and of course that was out of the question in this case. She got round the problem as best she could by interviewing as many Japanese as possible, Japanese who had emigrated to America before the war and Japanese prisoners of war. She also studied captured propaganda films, regular movies, novels, and the few other political or sociological books that had been published about Japan in English. As it happened, her study wasn’t completed until 1946, but when it did appear, published as The Chrysanthemum and the Sword, and despite the fact that it was aimed at policy makers, it created a sensation.49 There were still half a million American servicemen in Japan, as part of the occupying force, and this once terrifying enemy had accepted the foreign troops with a gentleness and courtesy that was as widespread as it was surprising. The Japanese were no less baffling in peacetime than they had been in war, and this helped account for the reception of Benedict’s book, which became much better known than her earlier fieldwork studies.50
Benedict set herself the task of explaining the paradox of the Japanese, ‘a people who could be so polite and yet insolent, so rigid and yet so adaptable to innovations, so submissive and yet so difficult to control from above, so loyal and yet so capable of treachery, so disciplined and yet occasionally insubordinate, so ready to die by the sword and yet so concerned with the beauty of the chrysanthemum.’51 Her greatest contribution was to identify Japanese life as a system of interlocking obligations, from which all else stemmed. In Japanese society, she found, there is a strict hierarchy of such obligations, each with its associated way of behaving. On is the name for the obligations one receives from the world around – from the emperor, from one’s parents, from one’s teacher, all contacts in the course of a lifetime.52 These obligations impose on the individual a series of reciprocal duties: chu is the duty to the emperor, ko to one’s parents – and these are subsets of Gimu, debts that can only ever be repaid partially but for which there is no time limit. In contrast, there is Giri, debts regarded as having to be repaid ‘with mathematical equivalence to the favour received’ and to which there are time limits. There is Giri-to-the-world, for example (aunts, uncles), and Giri-to-one’s-name, clearing one’s reputation of insult or the imputation of failure. Benedict explained that in Japanese psychology there is no sense of sin, as Westerners would understand the concept, which means that drama in life comes instead from dilemmas over conflicting obligations. Japanese society is based not on guilt but on shame, and from this much else derives.53 For example, failure is much more personally traumatic in Japanese society than in Western society, being felt as an insult, with the result that great attempts are made to avoid competition. In school, records are kept not of performance but of attendance only. Insults suffered at school can be harboured for years and may not be ‘repaid’ until adult life and even though the ‘recipient’ is never aware that ‘repayment’ is being made. Children are allowed great freedom until about nine, Benedict says, much more so than in the West, but at around that age they begin to enter the adult world of obligations. One result, she says, is that they never forget this golden period, and this accounts for many of the problems among Japanese – heaven is something they have lost before they are even aware of it.54 Another crucial aspect of Japanese psychology is that the absence of guilt means that they can consciously and carefully enjoy the pleasures of life. Benedict explored these – in particular, baths, food, alcohol, and sex. Each of these, she found, was pursued assiduously by the Japanese, without the attendant frustrations and guilt of the Westerner. Food, for example, is consumed in huge, long meals, each course very small, savoured endlessly, and the appearance of the food is as important as the taste. Alcohol, rarely consumed with food, often results in intoxication, but again without any feelings of remorse. Since marriages are arranged, husbands feel free to visit geishas and prostitutes. Sex outside marriage is not available to women in quite the same way, but Benedict reports that masturbation is available to the wife; here too no guilt attaches, and she found that Japanese wives often had elaborate collections of antique devices to aid masturbation. More important than any of these pleasures, per se, however, was the more widespread Japanese attitude that these aspects of life were minor. The earthly pleasures were there to be enjoyed, savoured even, but what was central for the Japanese was the interlocking system of obligations, mostly involving the family, such obligations to be met with a firm self-discipline.55
Benedict’s study quickly established itself as a classic at a time when such international cross-cultural comparisons were thin on the ground (a situation very different from now). It was thorough, jargon-free, and did not smack of intellectualism: the generals liked it.56 It certainly helped explain what many in the occupying forces had found: that despite the ferocity with which the Japanese had fought the war, the Americans could travel the length and breadth of the country without weapons, being welcomed wherever they went. The important point, as Benedict discovered, was that the Japanese had been allowed to keep their emperor, and he had given the order for surrender. Though there was shame attached to military defeat, the obligations of chu meant that the emperor’s order was accepted without question. It also enabled the conquered people the freedom to emulate those who had conquered them – this, too, was a natural consequence of the Japanese psychology.57 There were no hints in Benedict’s study of the remarkable commercial success that the Japanese would later enjoy, but with hindsight, they were there. Under Japanese ways of thinking, as Benedict concluded, militarism was ‘a light that failed,’ and therefore Japan had now to earn respect in the world by ‘a New Art and New Culture.’58 That involved emulating her victor, the United States.