In 1950 Dr. John Wheeler took leave of Princeton University to work on the development of the H bomb at Los Alamos. He brought with him a handful of students: one them was Kenneth Ford, the author of the book under review. The next year they joined Project Matterhorn which played an integral role in the development of Mike, the 10 megaton device that obliterated an entire Island of the Enewetak Atoll in the Marshall Islands. Before the test there were forty-one islands in the Atoll. Then there were forty.
This book is a weave of personal reminiscences of that two year period, portrayals of the personalities and rivalries of the central figures involved (John Wheeler, Robert Oppenheimer, Edward Teller, Stan Ulam and others), and simple explications of the physics of fission, fusion and the design of Mike.
There were fewer than fifty short years between the discovery of radioactivity in 1896 and the first wartime use of atom bombs against the Japanese in 1945. These early bombs were fission (as opposed to fusion) devices. It was easier to split a heavy, unstable nucleus and release its energy, than to fuse two lighter nuclei, releasing their binding energy. Nuclei consist of positively charged protons and neutral neutrons. So nuclei repel one another. To get two nuclei close enough together to fuse, one would have to overcome their electrical repulsion. Many physicists thought this was too great a difficulty to overcome with the technology of the time.
As late as 1949 Robert Oppenheimer argued against research into the design of fusion bombs because their construction would be technically infeasible and the their use would be immoral. However, by 1951 Teller and Ulam presented a “technically sweet” solution to the problem. Oppenheimer changed his mind and endorsed the project. Nevertheless, in 1954, the Committee on Un-American Activities questioned whether he still thought it was immoral to build and use such a bomb. He testified, “...when you see something that is technically sweet, you go ahead and do it and you argue about what to do about it only after you have had your technical success. That is the way it was with the atomic bomb.”
So why the term “H Bomb?” The ‘H’ is for hydrogen. The detonation of an ordinary, uranium fueled fission bomb is used to heat and compress a chamber of liquid hydrogen so compactly and energetically it fuses into helium. The hot neutrons ejected by the fusion process slam into an outer casing of uranium splitting its nuclei and ignite a second fission explosion. Mike and all later bombs are fission-fusion hybrids in this sense. A fission bomb is used to trigger a fusion bomb which, for good measure, ignites a second fission bomb. So the ‘H’ may as well stand for hybrid.
Matterhorn’s job was to calculate the yield of Mike. Ken worked many many nights writing and running programs on what today would be regarded as primitive computing machines. The equations he simulated were complex and given the limitations on computational power, they had to be somewhat crudely approximated. It turns out Mike, at 10 megatons (the energy one would release upon igniting 10 megatons of TNT), was nearly twice as powerful as the team predicted.
In 1954 a hybrid device known as Shrimp was tested in the Marshall Islands producing a yield of 15 megatons (1000 times the yield of the Hiroshima bomb). The shifting winds blew the fallout over several inhabited islands that had to be quickly evacuated. The crew of a downwind Japanese fishing vessel was exposed to radiation and one man died of radiation sickness. In 1958 doctors noticed milk was being contaminated by radioactive Strontium 90 as a result of nuclear weapons testing. These and other incidences sparked the drive toward test ban treaties. The first limited test ban treaty wasn’t signed until 1963.
Mike was Ken Ford’s last foray into the world of bomb making. At the time he argued that if the Soviets were developing H bombs, it would be best for the U.S. to develop one first. He doesn’t regret his work, but his attitude has been changed, beginning, he says, with America’s inexplicable involvement in Vietnam. He now questions whether any nation is sufficiently trustworthy or sufficiently moral to wield such weapons. He lends his voice to the cause of disarmament, “Zero is indeed the correct target number. Perhaps in your lifetime young reader. Not mine.”