by P. D. Smith
Unknown to the scientists on the Manhattan Project, from an early stage both government and military planners shared General Groves’s view that the real purpose of the atomic bomb was to target Japan so as to intimidate the Soviets. ‘The target is and was always expected to be Japan,’ wrote Groves in a memo to Secretary of War Stimson on 23 April 1945.52 According to Rotblat, the Manhattan Project scientists never for one moment imagined that the bomb would be dropped on Japan: ‘All our concentration was on Germany.’53
The evidence that Japan was always the real target emerged as early as 5 May 1943, just a few months after Fermi and Szilard’s pile went critical. The high-level Military Policy Committee, of which Groves was a member, ruled out using an atomic bomb on Germany because of the risk of an unexploded bomb falling into the hands of Nazi scientists. They agreed that the ‘best point of use would be on a Japanese fleet concentration’.54 The idea that from such an early stage Germany was not considered to be the main target deeply shocked Hans Bethe and other scientists, who learned of these secret notes only in 1995.
For Leo Szilard and his fellow émigrés, the threat was unquestionably from Germany’s formidable scientists and industrial expertise. They wanted an atomic bomb to deter Hitler from using one first. They never considered the possibility that such a weapon would be used against a non-nuclear nation.
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One man who was determined that the atomic bomb should be used on Japan was James F. Byrnes, President Roosevelt’s director of the Office of War Mobilization. Byrnes had told Roosevelt in spring 1945 that the atomic bomb could be politically dangerous: ‘if the project proves a failure, it will then be subjected to relentless investigation and criticism’.55 When Roosevelt died, his successor, President Truman, appointed Byrnes to the so-called Interim Committee, which discussed targeting. As his biographer has said, Byrnes believed that the bomb should be used as soon as possible in order to ‘show results’.56 He also ruled out any warning or a demonstration on an unpopulated area. He was equally opposed to sharing research on the atomic bomb with the Soviet Union.
The historian Ferenc Szasz has rightly pointed out that ‘the scientists who opposed the combat use of the weapon before August, 1945, were a small, out-of-power minority’.57 Foremost among that minority was Leo Szilard. In the spring of 1945 he had convinced Einstein to write another letter to the President, and this time Einstein asked if Szilard could meet Roosevelt to air his concerns about the use of the bomb. Roosevelt died before the meeting could take place, and the new President directed him to James Byrnes.
They met at Byrnes’s home at Spartansburg, South Carolina, in May 1945. Szilard was accompanied by Harold Urey. Both scientists were deeply concerned about how the use of the atomic bomb would affect both America’s reputation and the political climate of the postwar world. Szilard had written a document, originally for Roosevelt, which discussed these issues and the future of atomic energy. In it he predicted that the use of atomic bombs against Japan would lead not to peace, but to preparations for a new and more terrible war: ‘the first bomb that is detonated over Japan will be spectacular enough to start a race in atomic armaments between us and other nations’.58
He also warned that America’s enemies might one day ‘smuggle’ atomic bombs into the country and ‘carry them by truck into our cities’. They would be ‘virtually impossible’ to detect and could be used to blackmail the government at times of tension. ‘Such bombs,’ he said, ‘may remain hidden in cellars of private houses in our cities for any number of years or they may remain hidden below the ground buried in gardens within our cities or buried in fields on the outskirts of our cities.’ In this nightmare future he had sketched for America’s new leaders, Szilard described how suddenly and without warning ‘all of our major cities might vanish within a few hours’.59
Szilard predicted that in the post-war world there would be a race between America and the Soviet Union to build bombs. In six years they would be able to threaten the United States with devastation: ‘most of our major cities might be completely destroyed in one single sudden attack and their populations might perish’.60 To counter this and the future threat from nuclear-armed missiles, Szilard proposed a number of ingenious methods for the international control of atomic energy and arms.
But his words fell on deaf ears. It soon became clear that instead of negotiation, Byrnes preferred an aggressive foreign policy, similar to that described in Heinlein’s science fiction story ‘Solution Unsatisfactory’. Armed with the superweapon, he hoped to dictate a Pax Americana. The threat from the Soviet Union was uppermost in Byrnes’s mind. The war would be over in six months, he said, and Soviet troops were already in Szilard’s homeland, Hungary: ‘Russia might be more manageable if impressed by American military might’, he recalls Byrnes saying. ‘A demonstration of the bomb might impress Russia.’
Szilard was ‘completely flabbergasted’ by the idea that ‘rattling the bomb might make Russia more manageable’. The United States intended to intimidate the USSR. All Szilard could do was to try to impress upon the politician his fears that by using the bomb ‘we might start an atomic arms race between America and Russia which might end with the destruction of both countries’. Leo Szilard left the meeting more worried than when he arrived:
I was rarely as depressed as when we left Byrnes’ house and walked toward the station. I thought to myself how much better off the world might be had I been born in America and become influential in American politics, and had Byrnes been born in Hungary and studied physics. In all probability there would then have been no atomic bomb and no danger of an arms race between America and Russia.61
On his way back to Chicago, Szilard stopped off in Washington and met Oppenheimer, who was about to attend a meeting of the Interim Committee, set up that month to consider the use of the bomb. Szilard told him that he thought it would be a great mistake to drop the atomic bomb on Japan. Oppenheimer flatly disagreed.
‘The atomic bomb is shit,’ said the man who had built it.
Szilard was shocked. ‘What do you mean by that?’ he asked.
‘Well, this is a weapon which has no military significance,’ explained Oppenheimer, rather disingenuously. ‘It will make a big bang – a very big bang – but it is not a weapon which is useful in war.’62
Szilard could only shake his head in disbelief at Oppenheimer’s words. They served to further deepen his concerns. He did not place much hope in Oppenheimer and his three fellow scientists who had been appointed to advise the Interim Committee. Szilard was convinced that the committee itself had been carefully picked to include those in favour of using the bomb. The politicians wanted to frighten the Soviets, and the military wanted something to show for the $2 billion that had been spent on the atomic superweapon. And as far as Leo Szilard was concerned, the physicists advising the committee, including Fermi, were all ‘men who could be expected to play ball on this occasion’.63
General Groves was furious when he found out that Szilard had been to see Byrnes without asking permission. But ‘permission’ and ‘chain of command’ were alien concepts to Szilard. Once again, Arthur Compton – a member of the scientific advisory panel to the Interim Committee – stepped in as peacemaker. He attempted to mollify both sides by asking Szilard and his fellow Chicago scientists to set up their own committee to consider what should be done with the bomb and report back to the advisory panel. It was chaired by Met Lab physicist James Franck, who had worked on chemical weapons with Fritz Haber and Otto Hahn during World War I. Szilard and Eugene Rabinowitch were members of what became known as the Franck Committee. Its report (largely written by Szilard) proposed a demonstration of the bomb to ‘avoid mass slaughter but yet convince the Japanese of the destructive power of the bomb’. But, as Szilard later admitted, ‘what we did not discuss enough, was that Japan was defeated; the war could be ended by political means and need not be ended by military means’.64
When a demonstration of the atomic bomb over a
n uninhabited area was rejected by the Interim Committee, Szilard finally realized he was powerless to prevent its use against Japan. But he remained utterly convinced that this was the wrong decision and became even more determined that the voices of the dissenting scientists should be heard. At the very least, history should know that not every scientist agreed with the course of action adopted by Groves and Oppenheimer.
Szilard drafted a petition to put the scientists’ views on record. Fifty-three Chicago scientists signed the first version. All the leading physicists put their names to it, as did most of the biologists. But Szilard noticed that none of the chemists had. ‘This was so striking that I went over to the chemistry department to discover what the trouble was,’ he wrote later:
What I discovered was rather disturbing: the chemists argued that what we must determine was solely whether more lives would be saved by using the bomb or by continuing the war without using the bomb. This was a utilitarian argument with which I was very familiar through my previous experiences in Germany. That some other issue might be involved in dropping a bomb on an inhabited city and killing men, women, and children did not occur to any of the chemists with whom I spoke.65
Szilard also wrote to Edward Teller at Los Alamos asking him to circulate a petition, allowing those scientists who wished to register ‘their opposition on moral grounds to the use of these bombs in the present phase of the war’ to do so.66 Teller turned to Oppenheimer for advice. He was shocked by Oppenheimer’s ‘impatience and vehemence’ when it came to Szilard’s views. Oppenheimer argued that the use of the bomb was a matter solely for politicians and the military, not for scientists. What he didn’t reveal to Teller was that he – a scientist – was already advising the government on the use of the bomb. And his advice was to go ahead and drop it on a Japanese city.
Edward Teller’s reply to Szilard, dated 2 July 1945, is a remarkably revealing statement by a scientist justifying his fascination with superweapons and absolving himself of responsibility for their use. He told his friend that he had decided not to circulate the petition. ‘I have no hope of clearing my conscience,’ he said. ‘The things we are working on are so terrible that no amount of protesting or fiddling with politics will save our souls.’ Teller claimed to have worked on the bomb not from a sense of duty or pleasure, but ‘because the problems interested me’. He also cast doubt on Szilard’s stand against dropping the bomb. ‘I do not feel that there is any chance to outlaw any one weapon.’
In a clear reflection of Oppenheimer’s view, Teller says that ‘The accident that we worked out this dreadful thing should not give us the responsibility of having a voice in how it is to be used.’ He argued that secrecy must be lifted so that this responsibility can be ‘shifted to the people as a whole’. Having absolved scientists of responsibility for the use of their lethal handiwork, Teller placed his hopes on the distant prospect of world peace: ‘If we have a slim chance of survival, it lies in the possibility to get rid of wars.’ People needed to be convinced ‘that the next war would be fatal’. He concluded his letter thus: ‘I feel that I should do the wrong thing if I tried to say how to tie the little toe of the ghost to the bottle from which we just helped it to escape.’67
Despite this setback, Szilard did send copies of the petition to Los Alamos. But he didn’t hold out much hope that Teller’s colleagues would sign. Indeed, unknown to Szilard, one of them had even proposed dropping a dozen atomic bombs simultaneously on Japan. ‘Of course, you will find only a few people on your project who are willing to sign such a petition,’ admitted Szilard in his covering letter, ‘and I am sure you will find many boys confused as to what kind of a thing a moral issue is.’68 But the atomic scientists on the Hill were never given the opportunity to find out what a moral issue really was. Oppenheimer refused to allow the petition to be circulated.
The final draft of Szilard’s petition was written the day before the first atomic bomb was detonated in the New Mexico desert, creating for an instant a man-made sun on earth. The petition predicted that this ‘new means of destruction’ was just the first step on the road to an even more terrible weapon: ‘there is almost no limit to the destructive power which will become available in the course of their future development’. It also warned that the ‘nation which sets the precedent of using these newly liberated forces of nature for purposes of destruction may have to bear the responsibility of opening the door to an era of devastation on an unimaginable scale’.69 Here was a clear anticipation of the hydrogen bomb.
Eventually, 68 scientists registered their moral objections by signing. On 24 July, Compton, in his letter to Groves forwarding the petition, mentioned that a poll he had conducted of 150 scientists found a majority in favour of a demonstration of the weapon and a new offer to the Japanese to surrender. The petition never reached the President. By the time Groves sent it to Stimson, Truman had already attended the Potsdam Conference with James Byrnes, and was awaiting news of the superweapon’s use against the enemy.
Hiroshima, 6 August 1945 – the day on which the dreams of a scientific superweapon became reality. Jack London and H. G. Wells had imagined this day in fiction, and sown the seed in the collective consciousness. Humankind had been beguiled by terrible dreams of a weapon so awesome that a city filled with men, women and children could be destroyed by a single bomb dropped by a lone aircraft high up in the sky. Scientists such as Fritz Haber and Shiro Ishii had applied their specialist knowledge to realize this vision of a superweapon, but with only limited success. Leo Szilard knew that only physics could create such a weapon, but he had long dreaded the day when it became a reality. He feared that it might lead to war on an apocalyptic scale.
For the people of Hiroshima on the morning of 6 August, it was the beginning of just another humid, summer’s day. Across the city, people were heading off to work on bicycles and trams. In the parade grounds around the sixteenth-century castle, soldiers were stripped to the waist, exercising in the pale morning sunlight. There was scarcely a cloud in the sky, and the temperature was already edging up towards a sultry 30°C.
Some eight thousand schoolchildren were busy in the centre of the city, clearing firebreaks. In March, tens of thousands had died in firestorms unleashed by an incendiary attack on the capital. Hiroshima was the headquarters of the Japanese 2nd Army, home to over 40,000 troops. Their city was a target. But for some reason unknown to its people, Hiroshima had been spared the firebombs that had devastated other towns and cities in the Land of the Rising Sun. Soon the inhabitants of Hiroshima would understand why.
An air-raid warning had sounded just after seven o’clock, followed twenty minutes later by the all-clear. At 8.15 the drone of three B – 29 bombers caused some people to pause and look up anxiously. But what could a couple of planes do against a whole city? Thousands of feet above them in the blue sky, the big planes seemed like harmless, fragile silver insects. This time there would be no air-raid warning.
One minute later a new kind of bomb exploded 1,900 feet above the city of Hiroshima. The ferocity of the energies released – heat, light, nuclear radiation and pressure – was without parallel on the surface of the earth. A slug of the rare uranium isotope uranium– 235 had been fired into a sphere of uranium– 235 to create a critical mass. A little over 1 per cent of the uranium in the bomb (less than 2 lb) fissioned, instantly converting a tiny amount of mass into pure energy.70 But it was enough to blast the heart out of the sprawling Japanese city.
When the atomic bomb exploded it created a fireball. Its initial temperature was several million degrees centigrade, and its pressure several hundred thousand bars. On the ground immediately beneath the fireball – the point known as the hypocentre – the pressure ‘was estimated to be [between] 4.5 and 6.7 tons per square meter’.71 For a split second, the temperature on the ground soared to around 3,000 to 4,000°C; no element, including carbon, remains solid at 4000°C.
The thermal energy of an atomic bomb, a searing flash of electromagnetic radiation,
travels at the speed of light – 186,000 miles per second. People up to half a mile away were instantly burned to carbon, their internal organs evaporated, their charred and shrunken bodies locked in the precise position they were in at the moment of the explosion. Even a mile away, the temperature of exposed surfaces such as skin rose to a blistering 540°C.
As the fireball rapidly expanded, it created a destructive shock wave and a wall of air travelling at supersonic speed. Windows fragmented into a hail of lethal projectiles, driven by hurricane-force winds that tore clothing from bodies and lacerated flesh. Buildings were pulled apart like toys and set ablaze, casting a dense pall of dust and smoke over the city. A bright summer’s morning instantly became night.
The definitive Japanese account of the bombing describes what happened in those terrible moments immediately following the explosion:
With a violent flash that ripped the sky apart and a thunderous sound that shook the earth to its foundation, Hiroshima was pounded to the ground in an instant. Then, from where a whole city once was, a huge column of fire bounded straight up toward heaven. A dense cloud of smoke rose and spread out, covering and darkening the whole sky. The earth below became shrouded in heavy darkness. The dead and wounded lay fallen, piled up, everywhere: the carnage was like a scene in hell. Then, fires broke out all over and soon merged into a huge conflagration, which grew in intensity moment by moment. As a fierce whirlwind blew, half-naked and stark naked bodies, darkly soiled and covered with blood, began moving; in clustered groups resembling departed spirits, they staggered away in bewildered flight from the inferno. One after another fell down and died. Countless others lay trapped under fallen debris and were burned alive; their pathetic voices calling for family members, and for help, could be heard within the wildly dancing flames…