by P. D. Smith
Together with his two brothers, Engelfield has founded a doomsday cult, the Ark of the Brotherhood, which has an unhealthy obsession with the Book of Revelation. ‘I have a chance of performing the last and greatest experiment known to science,’ Engelfield tells Hooker. ‘To release the earth’s energy to destroy – I hope in a flash – the life on it.’ This mad scientist believes that life is an accident: matter ‘has no business thinking and feeling. That’s the mistake.’ For this reason, man is ‘doomed from the start. He can’t possibly find a lasting place for himself in this universe.’ As rational beings, our greatest achievement, says the coldly logical Engelfield, is to understand our ‘own noble despair’ and to grasp the ultimate pointlessness of life. Our ‘one last triumphant stroke’ is to choose the time of our death, like Socrates committing suicide, ‘leaving the mindless cosmos to its own damned dance of blind energies, for ever’.38
Engelfield’s scientific nihilism is strikingly similar to Satan’s stance in Imre Mádach’s The Tragedy of Man, the Faustian work that so impressed the young Leo Szilard. Humankind might be smart enough to understand the laws of nature, but we can’t do anything to change them. Ultimately, gloats Satan, man is powerless. That was the kind of pessimism that really infuriated Szilard.
At first, George Hooker is sceptical about Professor Engelfield’s claim that atomic energy could destroy the world: ‘We’ve been splitting atoms for years,’ he says. ‘You don’t even get a Nobel prize for it any more.’39 But although he thwarts the physicist’s doomsday plans, Hooker was wrong on this last point. For in the same year that The Doomsday Men appeared, scientists split the uranium atom clean in two. Not only did it win them a Nobel prize, but it meant that Szilard’s idea of a chain reaction was no longer a pipe dream.
It was not just Leo Szilard who was intrigued by the discoveries of the neutron and artificial radioactivity. Scientists around the world had also grasped the revolutionary possibilities. Foremost among them was Enrico Fermi. Together with his team in Rome, Fermi began systematically bombarding all the known elements with neutrons. Leo Szilard described this as an essential but ‘rather boring task’ which, if he had the money, he would have hired somebody else to do.40 But the brilliant experimentalist Fermi – whom Wolfgang Pauli labelled the ‘quantum engineer’ – was the perfect man for this exacting empirical task.41 He and his team spent 1934 and 1935 patiently bombarding the elements (including uranium) with neutrons. Unfortunately, Fermi misunderstood the nature of the results. He was not the only one: the whole of the physics community was mistaken about what happened when heavy elements were bombarded with neutrons.
The conventional wisdom at the time was that uranium absorbed neutrons to form bigger, artificial elements, which Fermi called transuranic (or transuranium) elements. A German chemist, Ida Noddack, had the temerity to point out in September 1934 that Fermi and the physicists had got it all wrong. She suggested that the uranium atom had split in two, forming elements lower down the periodic table. But Fermi dismissed this idea, and chemists, including Noddack’s friend Otto Hahn, advised her not to pursue this line of argument as the physicists found it frankly absurd. This mistaken advice was in fact a blessing in disguise. If physicists had understood in the 1930s what was really happening to the bombarded nuclei, Germany might have been in a position to develop atomic weapons during World War II. As Emilio Segrè, Fermi’s colleague, said later, ‘God, for His own inscrutable reasons, made everyone blind at that time to the phenomenon of nuclear fission.’42
In Berlin, Lise Meitner and Otto Hahn had spent the three years before 1938 bombarding uranium with neutrons and analysing the resulting products. In March that year, German troops occupied Meitner’s homeland, Austria. Because she was Jewish she was finally forced to flee the country in which she had worked for three decades. Before she left for Stockholm, where she had been invited to work, Meitner and Hahn held one last meeting to discuss the puzzling results of their research. In particular, Meitner advised her chemist colleague not to publish his latest findings on the bombardment of uranium. These seemed to suggest that radium – a lighter element than uranium – had been formed. But it was simply unthinkable that light elements could be created from heavier ones. It had to be a mistake. Further experiments were needed.
Lise Meitner spent Christmas 1938 in the small Swedish town of Kungälv, near Gothenburg. She invited her nephew, Otto Frisch, who was working at Niels Bohr’s Copenhagen Institute, to stay with her. It was, he later said, ‘the most momentous visit of my whole life’.43
When he arrived, Frisch found his aunt poring over a letter from Hahn. The content was ‘startling’.44 Hahn had written the letter late at night on 19 December. Working with his colleague Fritz Strassmann, he had now found that not radium but barium seemed to be produced when uranium was bombarded by neutrons. Barium, element 56 in the periodic table, is just over half the weight of uranium (number 92). Neither Hahn nor Strassmann could explain how this might come about. Hahn wrote in desperation to his exiled physicist colleague in the hope that she could come up with a suitably ‘fantastic explanation’.45 Lise Meitner did not disappoint them.
Otto Frisch simply couldn’t believe what Hahn had written.
‘Is it just a mistake?’ he asked.
‘No,’ replied his aunt without hesitation. ‘Hahn is too good a chemist for that.’46
The result of the experiment was so extraordinary that aunt and nephew decided to go for a brisk walk in the Swedish snow to see if they could work out exactly what had happened. Was it possible, they speculated, that the atomic nucleus was not a hard solid, like a rock, but had a soft, elastic structure, rather like a drop of liquid? Both George Gamow and Niels Bohr had already argued as much. Was this the evidence to support their hypothesis?
After Meitner and Frisch had been walking for some time, they sat down on a fallen tree trunk in the snowy landscape and began calculating whether the known electrical forces within an atom were consistent with such a structure. They concluded that the ‘uranium nucleus might indeed resemble a very wobbly, unstable drop, ready to divide itself at the slightest provocation, such as the impact of a single neutron’.47 And if the uranium nucleus had divided, as Frisch and Meitner were beginning to suspect, then as well as barium Hahn could also expect to discover krypton.48
But this was not all. Meitner calculated that the two nuclei created by the division of the uranium atom would possess a huge amount of energy, about 200 million electronvolts (MeV). The energy change in a chemical reaction is typically just a few electronvolts. At first the two physicists were puzzled about the source of this energy. Then they realized that a small amount of mass would be lost in the process of division, which Frisch later termed fission, after the process whereby two biological cells divide. About one-fifth the mass of a proton would be lost. Suddenly – thanks to Albert Einstein and relativity – all was clear. As Frisch explained, ‘whenever mass disappears energy is created, according to Einstein’s formula E = mc2, and one-fifth of a proton mass was just equivalent to 200 MeV… it all fitted!’49
On 3 January 1939 Frisch returned to Copenhagen, barely able to contain his excitement. When he broke the news to Niels Bohr, the Danish physicist struck his head with his hand in astonishment. ‘Oh what idiots we all have been!’ said Bohr. It was ‘wonderful’ news.50 Immediately Frisch and Meitner began writing up their explanation of this momentous discovery. As Meitner had now returned to Stockholm, they worked long-distance over the telephone. In the meantime, Bohr left on a prearranged visit to the United States and promised not to discuss the matter until Frisch and Meitner’s paper appeared.
Meitner immediately wrote to Otto Hahn telling him the remarkable news that she was ‘fairly certain’ that the uranium atom had split in two. ‘You now have a beautiful, wide field of work ahead of you,’ she promised. Poignantly, the exiled Meitner added that ‘even though I stand here with very empty hands, I am nevertheless happy for these wondrous findings’.51
; On 21 December 1938, the same day that Meitner received Otto Hahn’s extraordinary letter, Leo Szilard finally admitted defeat. He was now living in New York, at the King’s Crown Hotel, near Columbia University. His brother Bela and Trude Weiss had finally heeded his warnings about Hitler and had also moved to New York. But no one would listen to Szilard when it came to atomic energy.
After five years of research, even Szilard had to reluctantly admit that his dream seemed to be little more than what Lord Rutherford had always said it was – moonshine. Even Einstein laughed at the idea. He had recently told the New York Times science journalist, William Laurence, that no one would find the secret of atomic energy by bombarding the nucleus. ‘We are poor marksmen,’ said Einstein with a wry smile, ‘shooting at birds in the dark in a country where there are very few birds’.52 The day that Frisch and Meitner were learning of the discovery that would make his dream of a chain reaction reality, Szilard sat down and wrote a terse note to the British Admiralty asking them to withdraw his patent. It must have been a desperately hard thing to do.
On 16 January 1939, Niels Bohr arrived in New York on board the SS Drottningholm. On the pier to greet him were Enrico Fermi and his wife Laura. They had themselves arrived just the previous month, having emigrated from fascist Italy and its newly passed anti-Semitic laws, stopping off in Stockholm to pick up Enrico’s Nobel Prize in Physics. Laura Fermi thought that Bohr had aged: ‘He stooped like a man carrying a heavy burden. His gaze, troubled and insecure, shifted from the one to the other of us, but stopped on none.’53 Perhaps he had aged under the weight of the news he was carrying to the New World.
At first Bohr refused to discuss the discovery publicly, to allow Frisch and Meitner time to publish their paper and to claim priority. Hahn and Strassmann’s paper describing their experiment had appeared in Germany on 7 January but would not arrive in the United States until almost two weeks later. In the meantime, Leo Szilard remained in the dark.
During the transatlantic voyage, Bohr had discussed this revolution in the understanding of the atom with the Belgian physicist Léon Rosenfeld. Once in America, Rosenfeld went to Princeton where, knowing nothing of Bohr’s promise to Frisch, he began to spread the extraordinary news. A few days later, Leo Szilard happened to be in Princeton visiting Eugene Wigner, who was in hospital suffering from jaundice. Szilard was staying in his friend’s apartment and visiting each day to, as Wigner recalled, ‘raise my spirits with gentle Hungarian conversation’.54
It was at Princeton that Szilard heard about fission. It must have been an extraordinary revelation. Like Fermi and the rest of the physics community, he had believed that the heavy uranium nucleus was absorbing neutrons to create new, larger elements, or transuranics. Indeed, the Italian experimentalist had won his Nobel prize for ‘discovering’ these elements. Now that explanation had been overturned. Suddenly, Leo Szilard realized that the vision of a self-sustaining neutron chain reaction was within reach: ‘I saw immediately that these fragments, being heavier than corresponds to their charge, must emit neutrons, and if enough neutrons are emitted in this fission process, then it should be, of course, possible to sustain a chain reaction. All the things which H. G. Wells predicted appeared suddenly real to me.’55
In the course of their excited discussions in the Princeton infirmary, Wigner recalled that he and Szilard ‘developed all of the essential points of fission theory’. In the coming weeks, as physicists such as Bohr and John Wheeler began publishing papers on fission, Wigner was ‘pleased to see that… Szilard and I had seen farther… at several points’.56
Within days of learning about the fission of uranium, Szilard was writing to the financier Lewis L. Strauss (who would later chair the AEC), telling him about the ‘very sensational new development in nuclear physics’. Szilard still had no official position at a university and he was always on the look-out for a potential source of funding.
It was ‘exciting news for the average physicist’, he told Strauss. ‘The Dept of Physics at Princeton, where I spent the last few days, was like a stirred-up ant heap’. As ever, Szilard had his eye on future applications: fission might, he said, ‘lead to a large-scale production of energy and radioactive elements, unfortunately also perhaps to atomic bombs’.
One can share Szilard’s elation as he tells Strauss that the discovery has revived his high hopes of 1934, ‘which I have as good as abandoned in the course of the last two years’.57 The next day, despite developing a high temperature and a severe cold, Szilard made his way to the Broadway office of Western Union and cabled the British Admiralty:
REFERRING TO CP 10 PATENTS 8142/36 KINDLY DISREGARD MY RECENT LETTER STOP WRITING LEO SZILARD.58
As Leo Szilard was cabling London, Bohr and Fermi were discussing fission publicly for the first time, at a conference at George Washington University organized by George Gamow. Across America, researchers hurried to their laboratories to duplicate Hahn and Strassmann’s experiment. The media were quick to spot a good science story. POWER OF NEW ATOMIC BLAST GREATEST ACHIEVED ON EARTH, shouted the Washington Evening Star’s headlines; VAST ENERGY FREED BY URANIUM ATOM cried the New York Times at the end of January.59 Science Service, a leading news agency, sent a journalist to interview Bohr. His report tried to calm public fears of a new superweapon with apocalyptic potential:
First of all, the physicists are anxious that there be no public alarm over the possibility of the world being blown to bits by their experiments. Writers and dramatists (H. G. Wells’s scientific fantasies, the play Wings over Europe and J. B. Priestley’s current novel, Doomsday Men) have over-emphasized this idea. While they are proceeding with their experiments with proper caution, they feel that there is no real danger except perhaps in their own laboratories.
Science Service also played down the idea of ‘atom-motors’, and that ‘atomic energy may be used as some super-explosive, or as a military weapon’.60 Indeed, until 1943 Bohr remained sceptical about exploiting the power of the atom. That was the year in which he escaped from Nazi Europe and finally saw with his own eyes the astonishing scientific and industrial achievement of the Manhattan Project. Only then did he acknowledge that the atomic bomb was not just science fiction. In contrast, Szilard never needed convincing. ‘You know what fission means,’ he told Edward Teller in Washington that month. ‘It means bombs.’61
The American physicist Luis Alvarez was having his hair cut when he read the headlines about fission. With his hair only half-cut, he leapt from the barber’s chair and rushed to tell his colleagues at the University of California, Berkeley. One of them, Glenn Seaborg, said that the discovery of fission ‘seemed beautifully obvious’.62 Around the world, other physicists reacted similarly. In Warsaw the young Polish physicist and future winner of a Nobel Peace Prize, Joseph Rotblat, repeated Hahn and Strassmann’s experiment as soon as he heard about it. In April he travelled to England to work with neutron-discoverer James Chadwick. Within six months he was conducting feasibility studies on an atomic bomb.
Rotblat had ‘always believed that science should be used in the service of mankind. The notion of utilizing my knowledge to produce an awesome weapon of destruction was abhorrent to me.’ But an article by German scientist Siegfried Flügge on atomic explosives, published that summer in the renowned science journal Die Naturwissenschaften, raised the appalling possibility that Hitler’s scientists might build the bomb first. ‘The only way to stop the Germans from using it against us’, reasoned Rotblat, ‘would be if we too had the bomb and threatened to retaliate.’ It was the logic of deterrence, the rationale that would push the world to the brink of nuclear Armageddon during the second half of the twentieth century. But Rotblat later rejected deterrence because ‘a psychopath’ like Hitler would use atomic weapons even when faced with the threat of annihilation.63 As Szilard said in 1950, such a leader might even press the button of a doomsday machine.
Around the world, atomic physicists were quick to realize both the promise and the threat of the new discover
y. In Paris, Frédéric Joliot-Curie and his team immediately began exploring the possibility of a neutron chain reaction. But on 2 February 1939 they received a letter from Leo Szilard with a request that astonished them. He asked them to refrain from publishing anything on fission. Szilard had not made this extraordinary request lightly. A discussion with Enrico Fermi had left him deeply troubled. Isidor Rabi, at New York’s Columbia University, had told him that when he had raised the possibility that fission could lead to a bomb, Fermi’s response was ‘Nuts!’ Unfortunately, neither Rabi’s nor Szilard’s grasp of American slang was advanced enough to translate this expression. So they paid Fermi a visit.
When they tackled the Italian physicist about the chances of building an atomic bomb, Fermi reluctantly admitted, ‘well there is a remote possibility that neutrons may be emitted in the fission of uranium and then of course a chain reaction can be made’.
Rabi pressed him. ‘What do you mean by “remote possibility”?’
‘Well, ten per cent,’ said Fermi, grudgingly.
‘Ten per cent is not a remote possibility if it means that we may die of it,’ replied Rabi. ‘If I have pneumonia and the doctor tells me that there is a remote possibility that I might die, and it’s ten per cent, I get excited about it!’
