Professor Gareth Williams on why Christopher Nolan’s new blockbuster film Oppenheimer perpetuates a myth that the atomic bombs dropped on Japan in August 1945 were all-American inventions. Here he explains the British contribution to the story… <\/p>
I\u2019ve just seen Christopher Nolan\u2019s Oppenheimer<\/em><\/a>, which fully deserves its five-star rating. I also won a bet \u2013 that Nolan would perpetuate the pervasive myth that the atomic bombs dropped on Japan in August 1945 were all-American inventions.<\/p>\n We all know the story. Albert Einstein<\/a> writes a letter to President Roosevelt,<\/a> urging America to build an atomic bomb before the Nazis can.<\/p>\n Roosevelt sets up the Manhattan Project<\/a> under physicist Robert Oppenheimer and military engineer General Leslie Groves. Oppenheimer assembles a brilliant American team at Los Alamos, which designs and constructs the bombs. These destroy Hiroshima<\/a> and Nagasaki, precipitating the Japanese surrender and ending the Second World War.<\/p>\n I believed it too, until one morning in May 2017 when I was digging into the archives at Churchill College, Cambridge.<\/p>\n By accident, I came across top-secret documents, recently declassified, which painted a completely different picture. It was like stepping into a parallel universe, with names I didn\u2019t recognise \u2013 Frisch, Peierls, Oliphant, M.A.U.D. and Tube Alloys \u2013 and no mention of Oppenheimer, Manhattan or Los Alamos.<\/p>\n Then I realised that this was all happening in 1940, two and a half years before Manhattan was born, and decided to find out more.<\/p>\n The real story of the bomb began in Birmingham with two young physicists, Otto Frisch and Rudolf (Rudi) Peierls, both hounded out of Nazi Germany because they were Jewish.<\/p>\n When war was declared, the Home Office classified them as \u2018aliens\u2019 and barred them from the secret war project (radar) which swallowed up all their colleagues.<\/p>\n They therefore turned their attention to the extraordinary ability of a single neutron to crack the massive nucleus of uranium in two. Soon after the phenomenon was discovered in Berlin over Christmas 1938, Frisch coined the name \u2018fission\u2019 and showed that it released a huge blast of energy, a million times greater than detonating high explosive.<\/p>\n Days before the war began, Danish physicist Niels Bohr suggested that fission only occurred in a rare form of uranium, the isotope U-235, which constitutes less than one per cent of the natural element.<\/p>\n This made Frisch wonder what would happen if neutrons were fired into a mass of pure U-235. His calculations predicted a massive, explosive nuclear chain reaction.<\/p>\n He and Peierls estimated that a \u2018super-bomb\u2019 containing a few kilos of U-235 would explode with the force of tens of thousands of tons of TNT, and could devastate a city centre. They convinced their boss, Professor Mark Oliphant, who told them to write up their findings.<\/p>\n The Frisch-Peierls memorandum of April 1940 transformed the atomic bomb from fantasy into a series of technological challenges. In 1914, HG Wells invented the \u2018atomic bomb\u2019 for his novel, The World Set Free<\/em>, but the notion hadn\u2019t progressed beyond science fiction; the 40-ton \u2018explosive uranium device\u2019 in a 1939 French patent couldn\u2019t have worked.<\/p>\n A top-secret expert committee, including Nobel Prize winners, was set up in March 1940 to consider the Frisch-Peierls memorandum. It was cryptically named \u2018M.A.U.D.\u2019, from a garbled telegram about an old friend of Niels Bohr.<\/p>\n Being \u2018aliens\u2019, Frisch and Peierls were excluded and relegated to a technical subcommittee. In June 1941, the M.A.U.D. Committee\u2019s final report concluded that the U-235 super-bomb was entirely feasible and could be ready in two years, and that work must begin immediately to design the weapon and an industrial-scale process to extract U-235 from natural uranium.<\/p>\n But there was a catch: war-locked Britain lacked money and manpower, and was being pounded by the Luftwaffe. The super-bomb could only be built in collaboration with the Americans, and using a U-235 separation factory on American soil.<\/p>\n The M.A.U.D report was approved by the War Cabinet and forwarded to Winston Churchill<\/a>, and a copy was sent to the secret Uranium Committee in Washington. Its work done, M.A.U.D was dissolved and replaced by the Directorate of Tube Alloys, a consortium of British atomic researchers and industrialists, notably from Imperial Chemical Industries (ICI).<\/p>\n Meanwhile, British Intelligence reported that the Nazis had established a \u2018Uranium Club of top nuclear physicists before the war started, and were making progress towards making an atomic bomb.<\/p>\n The Americans were told this and had been sent copies of all M.A.U.D documents, but they didn\u2019t respond \u2013 and they ignored the final M.A.U.D report endorsing the U-235 super-bomb that could only be built in collaboration with the US. Their silence caused great concern and frustration in Britain.<\/p>\n In summer 1941, Oliphant flew to the US to advise on radar, and decided to find out why the Americans hadn\u2019t replied about the bomb. He was shocked by what he discovered.<\/p>\n The Advisory Committee on Uranium set up by Roosevelt in response to Einstein\u2019s letter was dysfunctional and populated by people incapable of understanding the bomb: military men who insisted that it took two wars to introduce a new weapon; physicists who were fixated on Enrico Fermi\u2019s nuclear reactor in Chicago and had written off the atomic bomb as too difficult and speculative; and a chairman, completely ignorant of nuclear physics, who locked the M.A.U.D report in his safe because he couldn\u2019t understand it, without showing it to his committee.<\/p>\n Oliphant was furious and went to argue the case for the bomb with an old friend, Nobel Prize winner Ernest Lawrence in Berkeley. Previously sceptical, Lawrence was converted by Oliphant into a fervent bomb believer, and in turn convinced key people above him that the British super-bomb must be taken seriously.<\/p>\n At last, the boulder began to roll. In October 1941, Roosevelt approved full Anglo-American collaboration to build the atomic bomb, and informed Churchill.<\/p>\n The collaboration made a slow start. At first, Churchill covertly stalled negotiations (he didn\u2019t want the Americans to get ahead technologically), which made the Americans lose trust in the British. The American bomb project gained momentum without the British, culminating in September 1942 with General Groves\u2019s appointment to run the top secret, $2-billion Manhattan Project.<\/p>\n This vast enterprise included the bomb-making base at Los Alamos, a huge U-235 separating factory in Tennessee, and a separate plant in Washington State to make plutonium, a man-made element created in Fermi\u2019s nuclear reactor which was even more explosive than U-235.<\/p>\n In October 1942, Groves appointed Oppenheimer to direct the scientists at Los Alamos. Oppenheimer soon realised that he needed British input and expertise, and against opposition from Groves, the \u2018British Mission to Los Alamos\u2019 was set up under James Chadwick, Nobel Prize winner for discovering the neutron.<\/p>\n The British made up fewer than one per cent of those at Los Alamos but punched far above their weight. U-235 would not have been ready for the Hiroshima bomb (Little Boy) without the theoretical input of Rudi Peierls and Klaus Fuchs<\/a>, together with a British-made nickel membrane that was crucial to the U-235 separation process.<\/p>\n Otto Frisch also calculated how much U-235 was needed from a terrifying experiment (likened to \u201ctickling the tail of a sleeping dragon\u201d) which came \u201cas close as we could possibly go towards starting an atomic explosion without actually being blown up\u201d.<\/p>\n The plutonium inside the bomb destined for Nagasaki (Fat Man) had to be imploded \u2013 crushed by conventional high explosives. The work of Peierls, Fuchs and James Tuck was vital in designing explosive \u2018lenses\u2019 to focus the shockwave, while British physicist Ernest Titterton devised the electronic firing signal that triggered the complicated detonation circuit.<\/p>\n Their impact? Without the British Mission, neither Little Boy nor Fat Man could have been built by August 1945 \u2013 or even by November that year, when America was set to invade the Japanese homeland if Japan didn\u2019t surrender.<\/p>\n And without Mark Oliphant\u2019s dramatic intervention in late summer 1942, the Manhattan Project would never have been set up, because nobody in America would challenge the assumption that an atomic bomb couldn\u2019t be made in time to play any role in the War.<\/p>\n