by P. D. Smith
On 1 November 1952, the darkness of the tropical night was rent by an artificial sun whose heat burnt the skin of sailors watching from thirty miles away. In an instant a small Pacific island called Elugelab was vaporized, leaving a crater more than a mile across. The fireball created by the hydrogen bomb was three miles wide, and a cloud of lethal radioactive by-products soared high into the stratosphere. Its awesome energy came from the same processes that fuel the sun – the fusing together of hydrogen atoms.
But the scientists had got their sums wrong. The thermonuclear explosion was more than twice as powerful as they had expected. The ‘Mike’ H-bomb test was the largest non-natural explosion the world had yet seen, equivalent to more than ten million tons of conventional high explosive. The Hiroshima bomb had the explosive power of a mere 12,500 tons of explosive. Even though it was a thousand times less powerful, it was enough to incinerate more than a hundred thousand Japanese, and fatally injure tens of thousands more.
Nobody has discovered a more powerful explosive than the hydrogen bomb – at least not yet. A year and a half after the Mike test, America exploded a bomb equivalent to 15 million tons of TNT (15 megatons in nukespeak). This test, at Bikini Atoll, remains the largest bomb ever detonated by the United States. But in the deadly game of one-upmanship that was the cold war, the Soviets had to go one step further. In 1961 they detonated a thermonuclear monster of about 60 megatons. It could have been bigger. The bomb’s yield had been limited for the test; the device was capable of 100 megatons.
The decision to develop the next generation of nuclear weapons in America had been made by President Truman in 1950. Even before his decision was announced, on 1 February, the New Statesman had declared that ‘the whole future of civilisation’ was at stake. The British journal argued that these ‘new weapons of mass destruction’ would make a Third World War ‘inevitable’. It would be a war fought by ‘methods of mass murder which would outstrip the wildest dreams of the SS and Himmler’.4
President Truman turned a deaf ear to such warnings and to the misgivings voiced by many leading scientists. Men such as James Conant and Robert Oppenheimer, who had played key roles in the Manhattan Project, as the atomic bomb project was code-named, left him in no doubt what they thought. In their official advice to the President they said the new bomb ‘represents a threat to the future of the human race which is intolerable’: it was a ‘weapon of genocide’. They also declared themselves ‘alarmed’ at the ‘possible global effects of the radioactivity’ from H-bomb explosions.
Enrico Fermi and his Nobel prizewinning colleague Isidor Rabi were also appalled by the prospect of working on the new bomb. They told the President: ‘The fact that no limits exist to the destructiveness of this weapon makes its very existence and the knowledge of its construction a danger to humanity as a whole. It is necessarily an evil thing considered in any light.’5
But when Truman convened the fateful meeting in the Oval Office of the White House on 31 January, their voices were not heard. The only one at the table who argued against the bomb (known as the ‘Super’) was David E. Lilienthal, the former head of the Atomic Energy Commission and a man with a mission to promote the brave new world of atomic energy. It was like saying ‘no to a steamroller,’ he said later.6
The sign on Harry S Truman’s desk read THE BUCK STOPS HERE. The no-nonsense President had made up his mind some days before the meeting. Four months earlier, the Soviets had shocked the world by testing their first atomic device. America was no longer the only atomic power in the world. In the words of one reporter, whether America liked it or not she was now a competitor in an ‘atomic rat race’.7 Time magazine, which regularly carried full-page advertisements for Boeing bombers (‘Potent weapons for world peace’8), spoke for the President in its editorial of 30 January: ‘The simple fact, unpleasant though it might be, was that if the Russians are likely to build an H-bomb, the US will have to build it, too.’9
For 42-year-old Edward Teller, the so-called father of the H-bomb, it was a personal triumph. Like Leo Szilard, the fiercely anti-Communist Teller was a Hungarian émigré. Even while Szilard and Enrico Fermi were designing and building the first atomic pile in 1942, Teller had been working on the calculations that would make the hydrogen bomb a reality. After the Soviet atomic bomb test, he campaigned tirelessly for the green light from the politicians. When Szilard heard that Truman had approved the H-bomb, he told a friend that ‘now Teller will know what it is to feel guilty’.10 As the man who had first urged President Roosevelt to build the atomic bomb, Leo Szilard was no stranger to guilt.
Television was the must-have consumer product in 1950. The year before there had been a million seven-inch black and white sets in America. Now there were ten times that number. Two weeks after what the press called President Truman’s ‘cosmic’ decision, the most famous scientist in the world made an appearance on television.11
A film crew descended on 112 Mercer Street, the picturesque weatherboarded house in the sleepy university town of Princeton that had been Albert Einstein’s home for the last fifteen years. It was the premiere of a new weekly discussion programme hosted by Eleanor Roosevelt. Seated at his desk dressed in what the New York Times described as ‘a sweater jacket and tieless, open-collared shirt’, Einstein declared that the world now stood on the brink of ‘annihilation’.12
With his famously unkempt hair and deeply furrowed brow, Einstein gave the impression of having grown weary of the world’s folly. In truth his health was failing. ‘I look like a spectre’, he told quantum physicist Erwin Schrödinger.13 But Einstein still cared passionately about promoting world peace. Now he genuinely feared that in its search for ‘the means to mass destruction’, science might endanger the world. If the project to build the hydrogen bomb was successful, he warned, then ‘radioactive poisoning of the atmosphere and hence annihilation of any life on earth has been brought within the range of technical possibilities’.14
In the studio discussion after Einstein’s filmed statement, David Lilienthal, Robert Oppenheimer and physicist Hans Bethe added their voices to the growing chorus of concern about the atomic arms race. But Lilienthal also tried to give atomic energy a positive gloss. He held up a two-pound chunk of uranium to the TV cameras and, as he had done many times before, boasted that it contained ‘the energy equivalent of thousands of tons of coal’. It was, he said, a ‘whole new source of energy to do man’s work’.15
Lilienthal declared that the future was atomic. But people had heard promises of unlimited energy before, and many were starting to wonder if they had a future at all in a thermonuclear world. When novelist William Faulkner had first met Einstein, he was so overawed by the great physicist that the wordsmith couldn’t speak. But in his Nobel acceptance speech in 1950, Faulkner captured the mood of atomic anxiety perfectly: ‘there are no longer problems of the spirit. There is only the question: When will I be blown up?’16
In the week before his appearance on Eleanor Roosevelt’s programme, Hans Bethe had tried to make the world a safer place. Together with eleven other leading scientists, Bethe, who had been a key figure in the Manhattan Project, made front-page news when he asked the United States Government to pledge that it would never be the first to use the hydrogen bomb. In 1938, the German-born Bethe had explained how the fusion of hydrogen into helium gave the sun its immense energy. Now he was being asked to build a bomb that would unleash that same energy on men, women and children. As the press pointed out even before the Mike test, when the H-bomb explodes ‘a little bit of the searing sun will have hit the earth’.17 Such a bomb, said Hans Bethe, was ‘no longer a weapon of war, but a means of extermination of whole populations. Its use would be a betrayal of all standards of morality and of Christian civilization itself.’18
But the fear of Soviet aggression was a powerful argument in favour of developing the hydrogen bomb, even for Bethe and his colleagues, who declared themselves willing to work on the project while condemning it as immoral. Harold C. Urey,
the man who won a Nobel prize in 1934 for discovering the H-bomb’s fuel, heavy hydrogen, spoke for many people when he said, ‘I value my liberties more than I do my life.’19
In Europe, where the after-effects of the last world war still scarred cities and people alike, the absurd logic of such statements (can you have liberty without life?) caused widespread alarm. Einstein’s apocalyptic warning was splashed across nearly every front page. In France the paper Aurore printed a startling headline across three columns: WHEREVER IT FALLS THE H-BOMB WILL OBLITERATE ALL HUMAN LIFE FOR A THOUSAND YEARS.20 You didn’t need Einstein’s brain to work out that Europe would be the battlefield of World War III. As the New Statesman put it, ‘the British people know perfectly well that, even if America and Russia might survive an atomic war, Britain and Western Europe would not.’21
These concerns were also being expressed in popular culture. The classic Boulting brothers film Seven Days to Noon, released in the year of the H-bomb decision, reveals both the growing anxieties about atomic war and a feeling that scientists had betrayed the ideals of their discipline. Professor Willingdon, a British scientist who worked on the Manhattan Project, disappears from his government research establishment together with an atomic bomb. Conveniently, the device fits neatly into the professor’s Gladstone bag – the first briefcase nuke. Willingdon threatens that, unless the British prime minister agrees to stop building atomic weapons, he will destroy twelve square miles of central London.
The professor, played by Barry Jones, is tormented by the thought that atomic war will mean the ‘total destruction of mankind’. People, he says, are ‘moving like sleepwalkers to annihilation’. Willingdon speaks for many real-life scientists at this time when he admits that he has ‘lost faith in the value of his work’. He had accepted the necessity of building an atomic bomb before the Nazis, but now he has been told to design an even more terrible weapon: ‘When I was a young man I saw in science a way of serving God and my fellow men. Now I see my life’s work used only for destruction. My dream has become a nightmare.’22 Leo Szilard was about to bring that nightmare one step closer to reality.
In homes right across America, people tuned in to the NBC radio network each Sunday afternoon to listen to the country’s most popular discussion programme – the University of Chicago Round Table. Broadcast since the 1930s, it had become a national institution. Even today the University of Chicago still proudly displays the actual table around which such opinion-formers as John F. Kennedy, Jawaharlal Nehru and Adlai Stevenson discussed the issues of the day. At a time when most programmes were scripted and predictable, the Chicago Round Table had a reputation for lively debates. Listeners who tuned in on 26 February 1950 were not disappointed.
Around the table that day were four scientists who had contributed to the Manhattan Project. Leading the debate was a dynamic, youthful-looking geochemist, Harrison Brown. One of his guests – Frederick Seitz – would later become a much respected president of the US National Academy of Sciences. Another – Hans Bethe – would win a Nobel for stealing the secret of the sun’s energy. The other participant that day was Leo Szilard, about whom a colleague once quipped that he was the greatest scientist never to have won a Nobel prize. Einstein was tieless for his appearance on national television. By contrast, the four scientists who faced each other on 26 February across the famous round table opted for dark suit and tie, even though it was a radio broadcast.
The University of Chicago Round Table, 26 February 1950. Around the table are (from the left), Harrison Brown, Frederick Seitz, Hans Bethe and Leo Szilard.
On the table stood a world globe, the kind that children love to spin. In front of each participant was an angled lectern for their notes. All four men knew each other well. Szilard, Brown and Seitz met every month or so at Einstein’s Princeton home, together with chemist Linus Pauling and biologist Hermann Muller, to discuss the political and social implications of atomic energy. This informal gathering of concerned scientists was known as the Einstein Committee.
It was Professor Bethe of Cornell University who initially took the lead in the Round Table discussion. He was an insider on the H-bomb project and a close friend of Edward Teller, the driving force behind the new bomb. Bethe pointed out that for now the H-bomb – or ‘Hell Bomb’ as it was known in the press23 – existed only in the minds of its would-be creators. But, he added cautiously, ‘it is possible that we can make this bomb’.24 It would use the energy of an atomic bomb to trigger a fusion reaction, which would be fuelled by heavy hydrogen. When it exploded, for a fleeting instant it would be as though a fragment of the sun itself blazed upon the surface of the earth.
Hans Bethe was ‘the living picture of the thinker’, the descendant of a long line of German university professors, recalled Laura Fermi.25 No one knew more about fusion than this dignified academic mandarin. In a soft but precise voice, Bethe explained that if it were built, the H-bomb would ‘certainly be very large,’ perhaps a thousand times as powerful as the Hiroshima bomb. In the future, he predicted, even the biggest cities, such as New York, could be destroyed with a single bomb.
Frederick Seitz, aged 39, had just become professor of physics at Illinois University. In the 1930s he’d been Eugene Wigner’s first graduate student at Princeton. This balding and rather grave-looking man was one of the eleven physicists who had supported Bethe’s call for America to rule out first use of the H-bomb. This afternoon he contributed a frightening figure to the debate.
The ‘flash effect’ of a hydrogen bomb would, he said, cover at least twenty miles. In other words, even that far from the explosion you would receive severe, life-threatening burns. At Hiroshima, where so many thousands of people were horrifically burned, the flash effect extended for less than a mile. The casualties from an H-bomb would be numbered in the millions, but no one around the table appeared visibly shocked. The figures they dealt with in their daily work were faceless.
Harrison Brown glanced down at his notes, and then turned to Hans Bethe, saying, ‘One sees in the press, from time to time, statements concerning destruction by another source – namely, radioactivity.’ This was the new possibility Einstein had raised on Eleanor Roosevelt’s programme. Today, Bethe confirmed Einstein’s worst fears about the invisible killer, radioactivity. He explained how the neutrons produced by the exploding hydrogen bomb would create radioactive carbon-14 in the atmosphere: ‘This isotope of carbon has a life of 5,000 years. So if H-bombs are exploded in some number, then the air will be poisoned… for 5,000 years.’ Almost as an afterthought, he added: ‘It may well be that the number of H-bombs will be so large that this will make life impossible.’
Leo Szilard was listening intently to Bethe, who was seated to his right. The German physicist was eight years younger than Szilard, who had just turned 52. The two scientists had very different characters. Bethe was a brilliant theorist as well as a good team player, an increasingly vital skill in the post-war era of so-called big science. Szilard thought teams belonged on football pitches. Science, for Szilard, was a personal battle of wits between him and nature. Einstein, who had been his friend for thirty years, shared this view. For both men, nature was a mysterious and sublime realm, a source of unending challenge and inspiration. Neither man liked the new corporate science that had grown out of the Manhattan Project, with its big budgets and bureaucratic procedures.
As Bethe finished speaking, Szilard’s eyes sparked with a sudden intensity. He had been waiting for this moment. He began by disagreeing with Bethe’s view of the threat from radioactivity. ‘It would take a very large number of bombs’, said Szilard, ‘before life would be in danger from ordinary H-bombs.’ But, he continued, ‘it is very easy to rig an H-bomb, on purpose, so that it should produce very dangerous radioactivity.’ He then proceeded to give his listeners, both around the table and in their homes across America, a lesson on how to construct a doomsday bomb.
First he explained how an atomic explosion creates dangerous radioactive elements. ‘Most o
f the naturally occurring elements become radioactive when they absorb neutrons,’ he said. ‘All that you have to do is to pick a suitable element and arrange it so that the element captures all the neutrons. Then you have a very dangerous situation. I have made a calculation in this connection. Let us assume that we make a radioactive element which will live for five years and that we just let it go into the air. During the following years it will gradually settle out and cover the whole earth with dust. I have asked myself: How many neutrons or how much heavy hydrogen do we have to detonate to kill everybody on earth by this particular method?’
Szilard paused and looked around the table as if expecting a reply. ‘I come up with about 50 tons of neutrons as being plenty to kill everybody, which means about 500 tons of heavy hydrogen.’
Harrison Brown watched Szilard intently, trying to absorb the implications of what he was saying. His head was large, almost imposing, but with chubby, boyish features. Swept back from a high forehead was a mane of thick dark hair through which ran a flash of grey. After his death, a friend would memorably describe Szilard’s boyish face as being like that of a ‘sad, gentle, mischievous cherub’.26
‘You mean, Szilard,’ said Brown, ‘that if you exploded 500 tons of heavy hydrogen and then permitted those neutrons to be absorbed by another element to produce a radioactive substance, all people on earth could be killed…?’
Szilard replied, ‘If this is a long-lived element which gradually settles out, as it will in a few years, forming a dust layer on the surface of the earth, everyone would be killed.’
