A Physics Café talk given at Explore Booksellers, Aspen, Aug. 28, 2023
Thank you all for coming here today. I imagine that a good number of you have seen the movie, Oppenheimer, which focusses on the remarkable character of J. Robert Oppenheimer, and especially on the confrontations at the 1954 Atomic Energy Commission hearings on his future security clearance. Only hinted at in the movie is the amazing effort to develop atomic bombs, primarily at Los Alamos – the secret town in northern New Mexico – but also at other secret laboratories including Oak Ridge in Tennessee, and Hanford in Washington State, all part of what was euphemistically called the Manhattan Project. What I would like to do in this hour is to give you a flavor of the history of the full development of what the historian Richard Rhodes, author of the monumental book, The Making of the Atomic Bomb, called, “arguably the single most important historic development of the 20th century.”
The movie and indeed the whole history raises many many questions that I will not get into today. The movie has been roundly criticized for what it did not show. To physicists it focusses too heavily on the 1954 hearings rather than the larger story. And more seriously, it does not get into whether dropping bombs on Japan made sense, or could have been avoided. It does not show any victims of the bombing of Hiroshima and Nagasaki. It also does not mention the people in the nearby Tularosa Basin in New Mexico who were irradiated by the Trinity test. And it does not deal significantly with postwar efforts to control atomic weapons. These are points I will also not discuss in this narrative, nor will I discuss the hydrogen bomb.
I have, as a practicing physicist, always been fascinated by the history, and in the mid-80’s took part, as a scientific consultant, in the writing of a technical history of the making of the bomb at Los Alamos. The history is published in a wonderful book called Critical Assembly, issued by Cambridge University Press in 1993. The title has several meanings, including the assembly of the bomb parts and the assembly of the people there. Over the years I got to know many of the principals involved, but not Oppenheimer, who died in 1967.
I also worked rather closely on nuclear and astrophysics with the great Hans Bethe, who appears in the movie, and who was the head of the theoretical physics division at Los Alamos. Bethe is the person who explained in 1938 how stars like the sun generate their energy through nuclear reactions – the process of nuclear fusion, in which hydrogen gets converted to helium, releasing lots and lots of energy. He also played an important role in the early days of the Aspen Center for Physics, where he gave part of his 1967 Nobel Prize money to build the Bethe Hall, appropriately named.

Hans Bethe and Gordon Baym, ca. 1985