Inside the Centre: The Life of J. Robert Oppenheimer (83 page)

Groves’s memo reached Potsdam on 21 July. By this time Churchill had already been told about Trinity, but Truman and his advisors were still unsure about how to play it with regard to the Russians. In a diary entry of 19 July, Stimson, reflecting on the repressiveness of Stalin’s regime and the contrast with ‘a nation whose system rests upon free speech and all the elements of freedom, as does ours’, recorded that he was ‘beginning to feel that our committee which met in Washington on this subject and was so set upon opening communications with the Russians on the subject may have been thinking in a vacuum’. When, two days later, Groves’s memo arrived, Stimson read it out in its entirety to Truman and Byrnes: ‘They were immensely pleased. Truman said it gave him an entirely new feeling of confidence. The memo was then shown to Churchill. The four of them, Stimson recorded in his diary, were ‘unanimous in thinking that it was advisable to tell the Russians at least that we were working on that subject, and intended to use it if and when it was successfully finished’.

^fn52
Thomas Powers (see
Heisenberg’s War
) believes that this drawing was given to Bohr by Heisenberg, but this was emphatically denied by Bohr’s son, which is why Bernstein developed the account that I have followed, which traces the origin of the drawing to Jensen’s visit to Bohr in 1943.

^fn53
The reason the word used in this context is ‘hydrodynamics’ rather than simply ‘dynamics’ is that, under the enormous pressure of implosion, the material used – uranium or plutonium – starts acting like a liquid rather than a solid.

^fn54
This was a more gradual process than Teller implies. The shift of focus from gun assembly to implosion, as I have tried to describe, was motivated by many different considerations and received many different impetuses, the visit to Los Alamos by John von Neumann being but one of them. The visit of Peierls was another. The really crucial development, however – the one that made it absolutely imperative to solve the problems of implosion – was the discovery in the spring of 1944 that it was impossible to build a gun-assembly bomb using reactor-generated plutonium.

^fn55
‘Hymne to God, My God, in My Sicknesse’.

^fn56
‘Holy Sonnet 14’.

^fn57
Given the experience of bombing up to that point, this is perhaps a natural assumption. However, as the ‘air raid’ in question would consist of a single aeroplane, there was little reason to suppose that the city’s occupants would realise they were about to be bombed. In fact, the inhabitants of Hiroshima did not pay much attention to the plane that dropped the bomb that destroyed their city, precisely because they did not – could not – imagine an air raid that did not involve a great number of aeroplanes.

^fn58
The date of the poll is a little uncertain because of a confusion in the record. The memo containing the results of the poll is dated 13 July 1945, but it gives the date of the poll as 18 July. Assuming that the memo was not, in fact, written five days before the events it describes, it seems most likely that the first date is an error and that the poll did indeed take place on 18 July.

^fn59
This was probably an exaggeration.

ON 23 JULY 1945,
barely a week after the Trinity test, the US Secretary of War, Henry L. Stimson, recorded in his diary a conversation he had had that day with George Marshall, the Army Chief of Staff, in which the two had agreed that ‘now with our new weapon we would not need the assistance of the Russians to conquer Japan’. The following day, Truman told Stalin about the atomic bomb. Or rather, as Truman later recalled it: ‘I casually mentioned to Stalin that we had a new weapon of unusual destructive force.’ To Truman’s great surprise, Stalin showed little interest. ‘All he said was that he was glad to hear it and hoped we would make “good use of it against the Japanese”.’ Stalin, of course, already knew a great deal about the Manhattan Project, and the Soviets had been told by Fuchs in May that a test of the bomb was being planned for July. What Truman and his advisors did not know was that the Soviet Union’s own atomic-bomb project was already well under way, accelerated by the information provided by Fuchs, Greenglass et al.

On the same day that Truman had this strangely muted exchange with Stalin, a directive – drafted by Groves and approved by Marshall and Stimson – was issued to General Carl Spaatz, the new commander of the Strategic Air Forces, which would be responsible for delivering the bomb. The air force, the directive stated, ‘will deliver its first special bomb as soon as weather will permit visual bombing after about 3 August 1945 on one of the targets: Hiroshima, Kokura, Niigata and Nagasaki.’ Two days later, the Potsdam Declaration was issued, calling for the Japanese to surrender and defining the surrender terms acceptable to the US and the UK, which, on that very day, had a new Prime Minister, Clement Attlee having decisively beaten Churchill in the UK’s general election.

‘The prodigious land, sea and air forces of the United States, the British Empire and of China,’ the declaration announced, ‘are poised to strike the final blows upon Japan.’ And therefore: ‘We call upon the government
of Japan to proclaim now that unconditional surrender of all Japanese armed forces, and to provide proper and adequate assurances of their good faith in such action. The alternative for Japan is prompt and utter destruction.’ Truman instructed Stimson that the directive of 24 July, ordering General Spaatz to deliver the bomb as soon after 3 August as the weather permitted, ‘would stand unless I notified him that the Japanese reply to our ultimatum was acceptable’. On 28 July, Radio Tokyo announced that the Japanese government would continue to fight. The official Japanese response was ‘Mokusatsu’, the meaning of which has been much debated by historians. It was interpreted by the US to mean ‘ignore’, but it can also mean ‘treat with silent contempt’. Neither meaning, of course, would constitute a response that Truman was likely to regard as acceptable, and so Japan had now to face the ‘prompt and utter destruction’ promised by the Potsdam Declaration.

At Los Alamos by this time the euphoria of the Trinity test had given way to a sombre mood, as they went about the task of preparing the bomb. In the minds of many was the dreadful realisation that, as Sam Allison put it: ‘They’re going to take this thing and fry hundreds of Japanese!’ The
High Noon
strut that Rabi had seen in Oppenheimer immediately after Trinity was no longer in evidence. His secretary, Anne Wilson, recalls that he looked depressed rather than triumphant, as if he were thinking: ‘Oh God, what have we done! All this work, and people are going to die in the thousands.’ One day, noticing that Oppenheimer seemed particularly distressed, Wilson asked him what was wrong. He replied: ‘I just keep thinking about all those poor little people.’

On the day of the Trinity test, the Little Boy casing was shipped to Tinian, an island in the western Pacific, south of Japan, from where the US air force had decided the atomic bombing raids would be launched. Soon afterwards the enriched uranium to be placed in the casing was flown out, the final assembly of the bomb to be performed by a team of about sixty people from Los Alamos, including Deak Parsons, Luis Alvarez, Phil Morrison and Robert Serber. For this specific task the scientists were put in uniforms and given ranks: Serber was, to his great pride, made a colonel, Alvarez a lieutenant colonel and all the others captains. Two huts at the air-force base served as ‘laboratories’, one for Little Boy, one for Fat Man.

Which of the four Japanese cities mentioned in the directive to General Spaatz would be the first to be bombed was not decided until a few days before the raid. On 30 July, Spaatz cabled Washington to say that he had heard that Hiroshima was the only one of the four that did not have Allied prisoner-of-war camps. In reply, he received orders that ‘Hiroshima should be given first priority’. That day, the assembly of Little Boy was completed and General Farrell reported to Groves that the mission could
be flown the following day, 1 August. This, however, proved to be impossible because of the weather, a typhoon making flying impossible.

The man chosen to pilot the B-29 bomber that would deliver the bomb was Colonel Paul Tibbets, who, on 4 August, after three days of anxious weather-watching, called a briefing for the crews of the seven planes that would be used during the mission (one for the bomb, three for a cloud-cover assessment the day before the drop, two to photograph and observe the bombing, and a seventh as a spare in case the first malfunctioned). The crewmen were astonished when they arrived at the meeting to find the briefing hut surrounded by military policemen armed with rifles. They were even more astonished when Tibbets introduced Deak Parsons, who told them that the bomb they were about to drop was the most destructive weapon ever made. When Parsons had finished, Tibbets took over to tell the men how honoured he and they were to be taking part in a raid that would ‘shorten the war by at least six months’.

The following day, Tibbets named the plane he had chosen to fly after his mother –
Enola Gay
– and hurriedly found a sign-writer to paint the name in foot-high letters immediately below the pilot’s window. A few hours later, at 2.45 a.m. on 6 August, the newly named
Enola Gay
set off from Tinian on its way to Hiroshima. Mid-flight, Tibbets announced to the crew that the weapon they were carrying was in fact an atomic bomb. The journey took more than six hours. At 9.14 Tinian time (8.14 a.m. local time), the bomb was dropped over Hiroshima. ‘Fellows,’ Tibbets announced on the
Enola Gay
’s intercom, ‘you have just dropped the first atomic bomb in history.’ What the crewmen experienced was a blinding glare, followed by two shock waves so intense they thought they had been hit by heavy guns. After the second shock wave, Tibbets has recalled: ‘We turned back to look at Hiroshima. The city was hidden by that awful cloud . . . boiling up, mushrooming, terrible and incredibly tall.’

As they looked back, the crewmen were awestruck to see that where, two minutes earlier there had been a city, there was now what one of them likened to ‘a pot of boiling black oil’. The tail gunner, Robert Caron, had the best view:

With a yield of 12,500 tons of TNT, the Hiroshima bomb was a good deal less powerful than the Fat Man tested at Trinity. To the people of Hiroshima, however, it was a destructive force the like of which none of them could previously have imagined. The temperature at the hypercentre of the explosion was an inconceivable 5,400ºF, enough to inflict primary burns on everybody within a two-mile radius. But it was not only the heat and power of the blast that terrified and confused the population of the city (estimated to have been about 255,000), but also the instantaneous suddenness of that power. ‘I just could not understand,’ one witness later said, ‘why our surroundings had changed so greatly in one instant.’ The appalling horror experienced by the inhabitants of Hiroshima was conveyed with searing intensity and vividness by the writer John Hersey in a long article, based on eyewitness accounts, that was published in the
New Yorker
in August 1946. Indeed, the magazine devoted its entire issue to the piece, something it had never done before and has never done since. It did so on this occasion, the editors explained, ‘in the conviction that few of us have yet comprehended the all but incredible destructive power of this weapon, and that everyone might well take time to consider the terrible implications of its use’.

The article was a publishing sensation. The issue sold out within hours of publication, the entire text was broadcast on the radio and a book version was rushed out, which became a best-seller. To some extent, Hersey’s account of Hiroshima was a fulfilment of the hope that Bohr had instilled in Oppenheimer and which became, in the absence of a genuine possibility that the Germans would build an atom bomb first, Oppenheimer’s rationale for building the bomb and recommending its use on civilians: the hope, that is, that the shock of seeing just how powerful the bomb was would be so great that the people and governments of the world would demand international cooperation to end war.

Certainly few things could be more shocking than the scenes described, with a restraint that makes them even more powerful, in Hersey’s article. Rather than attempting a synoptic overview of the destruction, Hersey concentrates on the stories of particular individuals, such as the Reverend Mr Kiyoshi Tanimoto, who, at the time of the explosion, was helping a friend to move some belongings to a house two miles out of town, where they would be safe from the bombing raids that they, like everyone in Hiroshima, feared and expected to come soon (Hiroshima being the only important city, other than Kyoto, that had thus far not been heavily bombed). Along the way, the two men heard the air siren that warned of the approach of American planes, and then the all-clear that was sounded when it was realised that only three planes were approaching. Then, just outside the house (so about two miles from the centre of the explosion), they saw a tremendous flash of light. Mr Tanimoto dived to the floor.
When he stood up again, he saw that his friend’s house had collapsed. He ran into town, thinking he could help people. As he approached the city centre, he passed hundreds of badly burned people fleeing in the opposite direction. There were collapsed buildings, fires and desperate, wounded people everywhere he looked. Wanting to rescue people trapped on sandspits in the river, he took a boat, which had been surrounded by a group of five nearly naked and badly burned men, and began to ferry the wounded away from the fires. At one sandspit Tanimoto saw a group of about twenty men and women, and, writes Hersey: