Leo Szilard, H. G. Wells, and What Oppenheimer Left Out
Or, Can an Artsy-Fartsy Novelist Make Sense of Nuclear Physics?
When I went to see Oppenheimer last week, the theater was mostly filled with dudes approaching middle age. It was the sort of audience that likely has strong opinions on Hoka vs. New Balance sneakers, Roth vs traditional IRAs, Wilco vs The National sad dad rock. My people, in other words.
The Oppenheimer Think Piece Industrial Complex is in full tilt, so I won’t talk too much about the movie. However, I’m delighted by the attention American Prometheus, Christopher Nolan’s source material, has received in recent weeks. Seeing a dense biography of a physicist atop the New York Times bestseller list is wonderful.
But if you pick up just one nuclear physicist biography this summer, may I recommend Genius in the Shadows: A Biography of Leo Szilard, the Man Behind the Bomb by William Lanouette. Like its subject, Lanouette’s 1992 biography has been unjustly overlooked. So who was Leo Szilard, why was he important, and what does H. G. Wells have to do with it?
Leo Szilard was a Hungarian Jewish refugee physicist who, as Lanouette writes, “did the most among scientists of his generation to help forestall, then create, then control the atom bomb.” He is portrayed in Oppenheimer, but the part is so small you may not remember him.
It’s a shame because Szilard is a more compelling figure than Oppenheimer. His ideas were more important to the success of the Manhattan Project, and he grappled more fully with what that terrible success meant. He was an ethical thinker who, in his spare time, did things like revise the Ten Commandments to help calibrate his moral compass. He understood that technological achievement and moral catastrophe were inextricably bound in the Manhattan Project. And, rather incredibly, an H. G. Wells novel plays an important part in all this.
Throughout the war, he clashed bitterly with Gen. Leslie Groves (played by Matt Damon in Oppenheimer). It isn’t depicted in the movie—presumably because it would undercut Damon’s portrayal of Groves as a gruff-yet-affable general—but Groves repeatedly tried to have Szilard arrested and interned as an “enemy alien” for lobbying against the use of the bomb on Japan.
This is all the more remarkable given that the Manhattan Project began with Leo Szilard.
Searching for Einstein
The road to Hiroshima begins, of all places, in the Belgian Congo. In 1938, Leo Szilard was alarmed to learn that German scientists had split the uranium atom. Five years earlier, he had developed the idea of nuclear chain reactions. The discovery of nuclear fission made his theoretic pipe dream a genuine possibility. Uranium was the only chemical element known to fission, and much of the world’s uranium lay in the Congo River basin. At the time, this region was a colony of Belgium, and Szilard could read a map: if Germany occupied Belgium and its territories, it would have access to the most productive uranium mines on earth. This, to Szilard, was unthinkable.
Szilard had recently arrived in New York and felt obligated to warn the Belgium ambassador. However, he faced a problem: no one knew who the hell he was. He was an obscure academic. I live in a college town where Obscure Academic is the median demographic. Let me tell you, few of them could get the Belgium ambassador on the horn in a pinch.
Though Szilard had conducted important research on nuclear chain reactions, he published little of it out of concern that his research might help Hitler’s scientists. While living in London he came up with the first nuclear reactor design, but convinced the British government to classify his patent as a military secret. Now he wondered if his insistence on secrecy robbed him of prominence when he most needed it. He did, however, have one thing going for him: he knew Albert Einstein.
So in July 1939, Szilard and another Hungarian physicist, Eugene Wigner, drove from Manhattan to Long Island in search of Einstein. For a trip with such a serious purpose, it was a bit of a farce. First, they drove to the wrong side of Long Island. When they finally arrived at the right town, they couldn’t find the right address. They must have been quite a sight: two Hungarian brainiacs wandering around the beach, asking random sunbathers where Einstein lived. Eventually, a child directed them to Einstein’s house.
Szilard’s insights deeply troubled Einstein. As Lanouette points out, the atomic bomb was an extension of Einstein’s own revolutionary E=mc², which recognized that mass is energy. But Einstein hadn’t followed his own equation to its natural conclusion until Szilard showed up on his doorstep. After listening to Szilard and Wigner, he agreed that they needed to warn the Belgians.
Wigner, the most pragmatic of the three, suggested giving the US government a heads up before alerting Belgium. The initial plan was to furnish US officials with a draft of the letter intended for the Belgian ambassador. But again, Szilard didn’t know who in the US government to approach. Through a series of intermediaries he found someone who did: Alexander Sachs, an executive at Lehman Brothers—yes, that Lehman Brothers—who had developed FDR’s response to the Great Depression.
Sachs told Szilard to forget the Belgians: FDR needed to hear this. Szilard would write two letters to Roosevelt and Einstein would sign both. Einstein receives credit for alerting FDR to the potential of a German atomic bomb, but what he really did was lend Szilard his name.
Genius in the Shadows depicts the absurdity of the scene through the perspective of Janet Coatesworth, a stenographer Szilard worked with at Columbia University:
As Szilard began to dictate, in his crisp Hungarian-German accent, a letter to “F.D. Roosevelt, President of the United States,” Coatesworth glanced up in disbelief. And when Szilard mentioned “extremely powerful bombs,” she recalled, “that convinced me! I was sure I was working for a ‘nutcase.’” Amused by her reaction, Szilard dictated more and more dramatically, his face beaming with mischief and merriment. He took special glee in closing the letter “Yours very truly, Albert Einstein.” That convinced her that Szilard was deranged, a judgement he confirmed by dictating a second, even longer letter. To Roosevelt. From Einstein. Only years later did Coatesworth learn the truth about this historic session.
Blackmailing Roosvelt
While the physics of nuclear fission are complex, the actual process is easily described. The University of Chicago—home of the first working nuclear reactor, which Szilard built with Enrico Fermi during the war—explains the process succinctly:
Some elements, like uranium, naturally throw off particles called neutrons as time goes by. The way a nuclear reactor works is by arranging uranium in just the right positions to encourage neutrons from uranium to hit other uranium atoms and cause them to split and throw off more neutrons, which split other atoms. This is why it’s called a chain reaction. But everything has to be positioned at just the right angles to keep the reaction going.
To keep the reaction going, Szilard knew he needed to slow its speed. At slower speeds, the neutrons shed from a uranium atom have a higher likelihood of hitting the nuclei of other uranium atoms, thus maintaining the chain reaction. The problem was finding a material that would moderate the speed of the chain reaction without absorbing the very neutrons necessary to sustain it. If you saw Oppenheimer, you might recall talk of “heavy water.” This is water formed with heavier hydrogen isotopes that slow the speed of neutrons. Another moderator, one that Szilard used, is graphite. (And if you saw Chernobyl, you’ll remember the role graphite plays in nuclear reactors).
Roosevelt took the 1939 Einstein-Szilard letter seriously, and his administration agreed to supply Szilard with the uranium and graphite necessary to determine if sustained nuclear chain reactions were even possible. But Washington moves at its own pace. Months passed. The uranium and graphite Szilard was promised did not arrive. Eventually, he decided he had no choice but to force Washington into action.
For the last several years, Szilard had browbeat, threatened, and cajoled his colleagues to refrain from publishing any research on atomic physics that might assist Nazi Germany. Now, he used what scant leverage he had: what he knew. He informed the Roosevelt administration that if he didn’t receive government assistance, he would publish a paper on nuclear chain reaction in an academic journal where friend and foe alike could read it.
As Lanouette notes, the first source Szilard cited in his paper was not the work of Einstein or Bohr or Heisenberg. It was a minor novel by a major author: The World Set Free by H. G. Wells.
Did H. G. Wells inspire the atomic bomb?
H. G. Wells might be second only to Shakespeare in his influence on popular culture. Consider what Netflix would look like without time travel or invading aliens. All you’d have left is the cooking shows. Over the course of his career, Wells predicted both the technology that dominates our world today and the tropes we use to make sense of it. Smithsonian Magazine made a handy list with just some of the technologies Wells’ fiction predicted: email, TV, cell phones, audio books, genetic engineering, lasers, space travel, and atomic bombs.
In 1913, H. G. Wells published The World Set Free, the novel Szilard credits as being one of the great influences on his life. This was the same year British radiochemist Frederick Soddy discovered the existence of isotopes. An element’s isotopes share the same number of protons but a different number of neutrons. For example, the vast majority of uranium is uranium-238, which has 92 protons and 146 neutrons. Uranium-235, the radioactive isotope necessary to make an atomic bomb, has 92 protons and 143 neutrons. If you were to chisel a hunk of uranium in the Congo River basin, it would be nearly all uranium-238. Enriching uranium—represented in Oppenheimer by the fishbowl of marbles—is the process of separating uranium-235 atoms from uranium-238.
Wells had long followed Soddy’s work (The World Set Free is dedicated to Soddy and his study on radium). He’d come to Wells’ attention following a series of experiments on radioactive decay with Ernest Rutherford.1 What particularly interested Wells, and what formed the basis for his novel, was the idea of “tapping the internal energy of atoms.”
The atomic bombs in The World Set Free are nothing like those depicted in Oppenheimer. Instead of a massive detonation, Wells imagined the blast of an atomic bomb as “a blazing continual explosion” that persists for years. What’s remarkable about this depiction, written twenty years before the neutron was even discovered, is its prophetic understanding of the long-term effects of nuclear radiation:
As with all radio-active substances this Carolinum [Wells’ fictional uranium-like element], though every seventeen days its power is halved, though constantly it diminishes toward the imperceptible, [it] is never entirely exhausted, and to this day the battle-fields and bomb fields of that frantic time in human history are sprinkled with radiant matter, and so centres of inconvenient rays.
Szilard was moved and troubled by The World Set Free when he read it in 1932, and he always credited it as what got him thinking about the dangers of atomic weapons. However, it wasn’t Wells but rather Soddy’s former collaborator, Ernest Rutherford, who more directly inspired the sequence of discoveries that resulted in the Manhattan Project.
Szilard was living in London in 1933 when he read a story in The Times that quoted Rutherford saying that “anyone who looked for a source of power in the transformation of the atoms is talking moonshine.” This annoyed Szilard, who thought that those who predict what can’t be done are usually shown to be fools. And, in this case, Szilard would do the showing. While walking down the street a few days later, he had his eureka moment. As quoted in Genius in the Shadows:
As the light changed to green and I crossed the street, it suddenly occurred to me that if we could find an element which is split by neutrons and which would emit two neutrons when it absorbed one neutron, such an element, if assembled in sufficiently large mass, could sustain a nuclear chain reaction.
That element, of course, would be uranium-235.
The influence of The World Set Free was more directly felt in the secrecy Szilard brought to his work. Over the coming years, he urged colleagues to hold back from publishing any research that Nazi scientists could use to develop an atomic weapon. By 1940, no one alive better appreciated the importance of atomic secrecy. And so when he threatened to publish his investigations into nuclear chain reactions, he may well have been bluffing. But the Roosevelt administration didn’t know that.
Nuclear Fallout
When the White House learned that Szilard would publish his research if he didn’t get the support he was promised, the uranium and graphite arrived promptly. The graphite was so heavy that the Columbia University football team was brought in to schlep it around.
After Pearl Harbor, Szilard moved to Chicago, where he worked with Enrico Fermi to create the world’s first nuclear reactor. Three years after Sachs’ presented his letter to FDR, nine years after he first conceived of the possibility of a nuclear chain reaction, Szilard’s hypothesis became reality.
As the war progressed, Szilard was increasingly marginalized within the Manhattan Project. This had nothing to do with his abilities as a physicist. Mostly, it was because he was a pain in the ass. Naturally distrustful of authority, he refused to submit to the chain of command. It seems the only English he never learned were the words yes and sir. Gen. Leslie Groves had him tailed by a half dozen undercover agents in an effort to gather enough compromising material to have Szilard arrested. To Groves’ dismay, there was nothing to find.
It’s a bit silly to graft mythological archetypes on recent historical figures, but if anyone involved in the Manhattan Project deserves comparison to Prometheus, it’s probably Szilard. His ideas were instrumental to the creation of the atomic bomb, but—unlike Oppenheimer—he was more interested in the atom as a creative rather than destructive energy source. Once he concluded that the Allies could win without the bomb, he risked his own freedom in a campaign to stop its deployment, displaying a moral courage absent in Oppenheimer. Again, from Genius in the Shadows:
Oppenheimer criticized the Chicago scientists in general and Szilard by name. Scientists had no right to use their prestige to influence political decisions, Oppenheimer complained. In fact, while denying Szilard the right to influence policy…Oppenheimer had advocated immediate bombing and had won the concurrence of his three reluctant colleagues by asserting his own status as lab director.
Perhaps the most notable difference between the two scientists is their political engagement. While Oppenheimer was persecuted for his leftist politics during the McCarthy era, Szilard had a deeper, more thoughtful understanding of the feedback loop between politics and technology. This awareness is what gives Szilard’s life its tragic dimensions: he tried to stuff the genie back into the bottle with one hand while releasing it with the other.
And it’s this—Szilard’s appreciation for how technology shapes politics even as politics shape technology—that makes him so relevant in an era dominated by the perils of AI and social media. It wasn’t just the nuclear age that Leo Szilard’s failures foretold.
I don’t know if Szilard ever reread The World Set Free after WWII, but if he did, there’s one passage that would have made him appreciate, once again, just how far over the horizon H. G. Wells could see:
The atomic bombs had dwarfed the international issues to complete insignificance. When our minds wandered from the preoccupations of our immediate needs, we speculated upon the possibility of stopping the use of these frightful explosives before the world was utterly destroyed. For to us it seemed quite plain that these bombs and the still greater power of destruction of which they were the precursors might quite easily shatter every relationship and institution of mankind.
Note: In addition to Genius in the Shadows and The World Set Free, I drew from Richard Rhodes’s excellent The Making of the Atomic Bomb for this post.
This work would eventually lead Rutherford to his model of the atom. He revealed his model in Manchester in 1911. As Richard Rhodes reports in The Making of the Atomic Bomb, “The first item on the agenda was a Manchester fruit importer’s report that he had found a rare snake in a consignment of Jamaican bananas. He exhibited the snake. Then it was Rutherford’s turn.” Thus the unveiling of the atom, one of the most consequential discoveries in history, received second billing to a weird snake.