What Oppenheimer Leaves Out From the True Story of the Manhattan Project

Christopher Nolan's Oppenheimer is a sweeping historical epic, but even that movie excludes some crucial details about its biggest characters and moments.

Cillian Murphy as Oppenheimer and flag main
Photo: Universal Pictures

This Oppenheimer article contains spoilers.

Oppenheimer is more than just 2024’s apparent Best Picture favorite and one-half of the “Barbenheimer” movement that shattered modern box office expectations. It’s a sweeping examination of the life of J. Robert Oppenheimer and how his work on the atomic bomb reshaped the course of human history.

Of course, even the most thorough examinations of significant real-life figures and events can’t quite cover everything you need to know about the true stories they try to tell. More importantly, many of those movies often intentionally alter or exclude certain details for the sake of storytelling. Understanding how complicated the filmmaking process can be is the key to understanding how such decisions are ultimately made.

Even a film as thorough as Oppenheimer can’t capture all of the real-life story it endeavors to bring to the big screen. Here are just a few of the more notable facts about the Manhattan Project, Los Alamos, and, of course, J. Robert Oppenheimer that you won’t find in Christopher Nolan’s epic.

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John von Neumann’s Crucial Role in the Manhattan Project

While Oppenheimer largely focuses on the personal life and works of its titular lead character, the movie does find time to at least introduce us to many of the other scientists working at Los Alamos. Yet, the film doesn’t even reference one of the most significant real-life contributors to the Manhattan Project: John von Neumann.

At the risk of oversimplifying his legacy and accomplishments, Neumann is widely considered one of the most influential and intelligent mathematicians ever. In terms of the Manhattan Project, he sometimes served as the mathematical counterpart to Oppenheimer’s role (a necessary structural dynamic that the film references). In that position, Neumann came up with (or directly contributed to) many of the structural elements of the atomic bomb that ultimately made it work.

From a policy perspective, Neumann was also on the committee that chose the initial bombing sites and was a pioneer of what would eventually become the theory of mutually assured destruction. Perhaps more importantly, he was a long-time friend of (and frequent political/professional rival to) Oppenheimer himself. The two had known each other since college, and Neumann would later have a lot to say both in defense and critique of Oppenheimer when his colleague’s work and views were being heavily scrutinized during the later parts of his life.

So why isn’t Neumann in the movie? There is no official answer to that question, but it’s easy to assume that it was a simple matter of logistics. For as important as Neumann was to the Los Alamos project, he wasn’t stationed at Los Alamos full-time, which means he wouldn’t have been present quite as much as some of the other characters. The extent of his contributions may have also been much more difficult to convey in a movie that has so much more ground to cover. Nolan also seems to have decided to focus on Albert Einstein as the “other” notable genius of that era, which makes sense when you consider the cultural weight that Einstein brings into the picture with little explanation needed.

Arthur Compton’s Advice to Oppenheimer Regarding World Destruction

Much like John von Neumann, Arthur Compton was a vital contributor to the Manhattan Project who is not directly featured in Oppenheimer. What’s particularly interesting about Compton is how the movie so clearly replaces him with another historical figure in ways that ripple throughout the film.

Not only was Compton partially responsible for some of the vital research that preceded the start of the Manhattan Project, but he was essentially the person who assigned Oppenheimer to that project in the first place. In fact, the two were so close that Oppenheimer later visited Compton to get Compton’s advice on a theory that suggested the detonation of the atomic bomb could trigger an atmospheric chain reaction that may eventually destroy the world. Though that theory is prominently referenced in Oppenheimer, the movie suggests that Oppenheimer doesn’t visit Compton for advice regarding his fears but rather goes to see Albert Einstein. It’s another example of the movie essentially using Einstein as a surrogate for multiple outside advisors to expedite both the narrative and the dramatic impact of those moments.

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It’s also worth noting that the movie arguably overplays the initial significance of that theory due to its dramatic value and how it relates to the broader themes of the film. For instance, Hans Bethe (the head of the theory team at Los Alamos) later expressed doubt that the theory of global destruction in that context was ever a viable concern and that it may have been based on some inaccurate calculations in the first place.

The Nuclear Fallout of the Trinity Test

In Oppenheimer, much is made of the location of the Los Alamos project, both in terms of its personal significance to Oppenheimer himself and the necessity of utilizing such an isolated location for the test detonation. However, the real-life location of that test may not have been quite as isolated as the movie would lead you to believe.

The test bomb was actually detonated a couple of hundred miles away from the main Los Alamos base camp at a location that was actually surprisingly close to some towns, camps, and other pockets of civilization. To this day, there is some debate as to how close civilians were to the blast, but the explosion could reportedly be heard and felt up to over 100 miles away. It’s even been suggested that the full fallout of the blast may have reached most of the U.S. in some way and even parts of Canada.

Those closest to the blast certainly witnessed the most obvious immediate consequences of the occurrence, though. In fact, some people living in the nearby Ruidoso, New Mexico camp later reported that children were playing in the snowfall-like debris that the blast caused. Much of that confusion was the result of the U.S. government’s desire to keep the nature of the test a secret. U.S. officials later tried to publicly explain that the event was the result of a munitions explosion. Their desire for secrecy also meant that they crucially chose not to evacuate the relatively nearby area ahead of the test.

In the years and decades that followed, some of those who lived downwind of the explosion reported various negative effects that ranged from polluted water to a significant increase in infant mortality rates and cancer diagnosss. While the U.S. government would later pass the Radiation Exposure Compensation Act to help compensate the so-called “Downwinders” (and others impacted by nuclear test programs), the exact fallout of the test has long been a point of political and historical contention. It’s difficult to properly determine both the extent of the event and how aware those involved with the project may have been regarding the short and long-term negative effects of their tests.

The complex consequences combined with the fact that many of those consequences didn’t become a bigger talking point until years after most of the events portrayed in Oppenheimer is likely the biggest reason why this topic isn’t explicitly discussed in the movie. Still, while the film acknowledges the horrific long-term effects of these weapons in its own ways, understanding the aftermath of that “test” is an important part of understanding just how much harm it caused and what was sacrificed along the way.

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The Murder Conspiracy Behind Jean Tatlock’s Death

As we’ve discussed elsewhere, Oppenheimer fails to devote enough time to the women who helped shape the film’s story. Many of those women were not only fascinating historical figures but there were significant events in their lives that enhance our understanding of many of the movie’s bigger events and themes. Few of those events may be more fascinating than the suspected murder of Jean Tatlock.

As noted in the movie, Tatlock’s relationship with Oppenheimer and outspoken political views eventually “inspired” the FBI to put her under active surveillance. She was allegedly still under surveillance when she died on January 4, 1944, as the result of an apparent suicide. However, the specific events of Tatlock’s death have long been debated. Not only do some of the events that immediately preceded her death not quite align with a typical suicide attempt, but the curious presence of chloral hydrate in her blood could never entirely be explained. Such details inspired a compelling theory that Tatlock was murdered by government officials due to her potential knowledge regarding Los Alamos and Oppenheimer and how her political beliefs may have caused her to leak that knowledge to communist governments. Indeed, American Prometheus (the book that Oppenheimer largely draws from) contains a statement from a doctor that refers to chloral hydrate as a potentially effective tool for a discrete assassination.

To be clear, Tatlock had a documented history of clinical depression (at least as it was understood at the time) and there are certainly numerous pieces of evidence surrounding the events of her death that support the initial suicide ruling. Furthermore, there are theories regarding how chloral hydrate may have gotten into her blood that do not involve an assassination attempt. Though Oppenheimer does hint at the possibility that Tatlock was murdered in a brief dreamlike scene that shows a black glove pushing Tatlock’s head underwater, the movie simply doesn’t choose to devote more time to the horrifying possibility that Tatlock’s associations with Oppenheimer may have directly contributed to her tragic death.

Ted Hall Was Los Alamos’ Other Spy

Oppenheimer not only discusses the spy who infiltrated Los Alamos but it grants a fair amount of screen time to the person who the movie would later identify as that spy: physicist Klaus Fuchs. What the movie doesn’t tell you is that there was another prominent spy at Los Alamos named Theodore Hall whose story is honestly worthy of its own movie.

Theodore Hall began working on the Manhattan Project when he was only 18. Despite his incredibly young age, Hall was such a respected physicist that he was eventually put in charge of the team that was responsible for implementing and designing the atomic bomb’s implosion device. Fairly early into the process, though, Hall joined those Los Alamos scientists who expressed concerns that the bomb would not be used on Germany as was originally suspected and would ultimately put the United States in a potentially dangerous position of power. Those concerns reportedly fueled his decision to eventually start relaying information about the project to Soviet officials.

Remarkably, Hall wasn’t publicly identified as a spy until many years later despite evidence of his espionage being discovered as early as 1950. Why? Well, one of the more popular theories suggests that the US did not want to reveal the codebreaking technology they had used to uncover Hall’s deception by prosecuting him as an informant. A later investigation into the matter theorized that J. Edgar Hoover and others may have also been concerned about prosecuting scientists who would later go on to play vital roles in subsequent military projects. The idea seemed to be that their ongoing contributions were more valuable than the act of ousting and arresting them.

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Though this is another historical topic that Oppenheimer simply decided to expedite a bit rather than cover in greater depth, those who are interested in learning more about Ted Hall’s life should consider checking out the excellent 2022 documentary A Compassionate Spy which discusses and investigates much of Hall’s life.

Oppenheimer is streaming now on Peacock.