A Manhattan Project historian comments on ‘Oppenheimer’

With any film about a historical event, one can expect portions of the movie will be accurate and others modified for theatrical purposes. Those who are familiar with the story of the Manhattan Project and of the life of its chief scientist, J. Robert Oppenheimer, will have a slightly different lens to view Christopher Nolan’s adaption of the Pulitzer Prize-winning book, American Prometheus, written by Kai Bird and Martin J. Sherwin. I leave it to professional critics to discuss the merits of the film, which overall I found excellent, and will give a slightly closer look at some technical details shown in the film.

Nolan walked the fine line of providing enough technical details to tell the story of the Manhattan Project, but not as much as to require a college degree in physics to understand what was happening. Some of the film’s simplifications were done by almost completely ignoring the work performed at other Manhattan Project’s sites—namely at Hanford, Washington, and Oak Ridge, Tennessee. Their only mention was in reference to their production of fissionable materials, as Oppenheimer drops representative marbles into glass bowls. From all my readings about the subject, this scene was purely fictional, but it did convey very well the challenge the project faced as it raced to produce enough materials for the weapons Oppenheimer and his fellow scientists were developing at the Los Alamos Laboratory. I think the sense of the scale of the Manhattan Project is probably not palpable from the film.

For many viewers, one of the “surprises” is probably the scene of Oppenheimer poisoning the apple for Patrick Blackett, his tutor at Cambridge. Unless you have a collection of books about Oppenheimer’s life on your bookshelf, this event is usually one that is not often told and certainly one that looked fictional. But, as surreal as it looks, this event did happen, and the only uncertainty was the exact poison that he used. Since Potassium Cyanide is a poison known to most moviegoers, Nolan made the choice to use that as a clear indicator of what was occurring. As to Oppenheimer being introduced to Niels Bohr by his mentor at Cambridge, Patrick Blackett, it is incorrect. That introduction was made via Ernest Rutherford, the head of the Cambridge Lab, in the spring of 1926. The conversation between them that follows, however, is factual.

Nolan’s film also tends to distort the Bohr-Heisenberg connection. For those unaware, there was a meeting in September 1941 in Copenhagen between the two scientists. What happened at the meeting is still debated to this day: Was Heisenberg warning Bohr that Germany believed it could make an atomic weapon? Or was he hoping that Bohr might prevent the United States from pursuing the development of an atomic bomb to be used against Germany? After Bohr’s dramatic escape (which is partially told in the film), he would have lent more insight to the key figures as to his understanding of the German program.

As for the accuracy of the film’s depiction of the Trinity test itself, Nolan decided early on that he would not use computer generated imagery (CGI) for the explosion, but rather practical effects. For too long, audiences have been conditioned to hear and see a nuclear explosion as one simultaneous event. But Nolan’s Trinity explosion is correct: A light “brighter than a thousand suns” flashes across the screen and, seconds later, the tremendous roar and blast wave reaches the observers. (To see the actual footage of the Trinity test and sound delay, I recommend watching the documentary, Trinity and Beyond.) However, I was expecting to see how the mushroom cloud form and grow, which is to experts a very familiar shape, but that did not occur in the film. For most viewers, though, this omission will go unnoticed. I did like the fact Nolan included initially moving the mattresses under the Gadget while it was first being lifted up the test tower. This was a nice factual detail for those who caught it.

A minor issue I had was with Donald Hornig and the kill switch. Hornig, a Harvard trained physicist, was the one who designed the high-voltage capacitors that were needed for the implosion to be triggered. I am not certain that this switch was actually a big red button, however perfect for the screen. I had read instead that he actually had his hand on the switch—not near it—as he was well aware of the fast reaction time he would need to stop the test.

Nolan did capture many of the events that actually occurred at Compania Hill (an observation point located about 20 miles northwest of ground zero), from Edward Teller applying sunscreen to Ernest Lawrence initially wanting to watch it from inside the car. (Richard Feynman remained in the car and was probably the only person to view the test directly.) I did find, however, the film’s over-emphasis on the atmospheric ignition debate a bit too much. I do not recall ever reading that Oppenheimer spoke with Einstein about this issue. First, that was not Einstein’s area of expertise. Second, that would have been a big security breach as well. It was Hans Bethe who first confirmed that the probabilities for an atomic bomb explosion to ignite the atmosphere and destroy the world were “near zero” (nothing is ever zero in quantum mechanics). The calculations were checked again by another physicist, Emil Konopinski, who would later suggest the use of tritium as a fuel for the hydrogen bomb.

The film skips back and forth through time as it weaves its story. This gets complicated when the film covers both Oppenheimer’s Atomic Energy Commission security hearing, which occurred in 1954, and Strauss’ congressional confirmation hearing in 1959. I suspect many viewers may have believe these events happened in parallel.

Another questionable scene was the ending of the post-war meeting between President Truman and Oppenheimer. In the film, we hear Truman telling Dean Acheson, his State Secretary, that he never wants to see this “crybaby” again. Truman actually made his comment about Oppenheimer almost a year after their meeting in a letter to Acheson. Truman’s reaction to Oppenheimer’s “blood on my hands” lament is also a bit murky, as the accounts of the meeting have changed over time. However, the intent of the response from Truman is correct.

The last comment I have on the film is more about how little was truly shown regarding the horrors of dropping the atomic bombs over Japan. Viewers only get one scene at Los Alamos, in which it looks like Robert Serber—who had gone to Hiroshima and Nagasaki to document the bombings—appears to present a slideshow of photographs to the scientists. But none of that imagery is shown to the viewers. Instead, we see Oppenheimer’s own reaction to those images—an obvious deliberate choice by the film director. The closest we get to seeing the reality of the atomic bombings is when, leaving the presentation, Oppenheimer steps into a charred corpse during a nightmarish sequence. For those familiar with the unclassified photos from Hiroshima, this corpse looked very close to one of those photos of a charred victim.

Nolan’s film cannot be considered technically accurate throughout. But for any Hollywood adaption, adjustments must be made. Overall, I think the film is close enough to the historical events, and most of the adjustments made were for understandable artistic reasons. I am sure other technical elements will pop up to my eyes—and those of other experts—after watching this immensely dense film again.