Forbidden History - Heisenberg and the Atomic Bomb

Episode Date: March 13, 2025

As one of their most controversial scientists, Heisenberg was key in the Nazis' efforts to develop an atomic bomb. But how close was he to succeeding? Cast List: Dr Gerhard Rammer: Deutsches Technikmuseum Shalina Patel: Historian  Guy Walters: Author and Historian  Dr. Mark Walker: Union College, New York  Nigel Jones: Author and Historian  Dr. Kathryn Olesko: Georgetown University Dr. Magnus Brechtken: Leibniz Institute for Contemporary History Gunhild Lurås: Norwegian Industrial Workers Museum  Dr Katherine Sharp Landdeck: Texas Woman’s University  Egidius Fechter: Atomkeller Museum Eric Meyers: Narrator  Learn more about your ad choices. Visit megaphone.fm/adchoices

Welcome to the Forbidden History Podcast. This program is presented solely for educational and entertainment purposes. It contains mature adult themes. Listener discretion is advised. Japan. August 1945. An event that changed the course of history. This doesn't look like a larger conventional weapon. It's something more heinous and something really to be feared.

In the culmination of a race for an atomic bomb, The USA had catapulted the world into the nuclear age. One of the greatest fears of the Allies during the war was that Nazi Germany would get its own nuclear weapon. The Nazis would absolutely have used this new weapon to win this war, and it doesn't bear thinking about, really does it? This was the American motivation for building the bombs in the first place. It was incredibly important to the Allies

to do whatever they could to try to. to stop the Nazis from progressing. The effort to build this weapon required the world's greatest minds. In Germany, one man stood out, Werner Heisenberg. He was a genius. He was a German scientist living at the top of his game in Nazi Germany. But the German attempt to become a nuclear power failed, leading to some questions about Heisenberg's role in the matter.

This really quite mysterious character, he's very hard to grasp. Is he a sympathizer of the Nazi state? Difficult to say. He never joined the Nazi party. But he was so loyal to Germany. He wanted Germany to win. 80 years on, his motives remain a mystery. So did he really try to slow things down, or was he trying to make atomic weapons for Germany?

In September 1941, most of Europe is under Nazi control. As the war raged across the continent, Werner Heisenberg, lead figure in the German atomic research program, traveled to occupied Denmark. One of the events in Heisenberg's life during the war that's had a lot of people debating it for 80 years was the meeting in Copenhagen with Neal's Bohr. Neil's Borr had won a Nobel Prize for physics and he had mentored Heisenberg and they'd become really close friends. They were two of the most influential physicists in the world, a German working for the Nazis and a Dane of Jewish heritage. And it seems like something was said during that meeting which potentially had wider repercussions on the whole outcome of the war. It's always been speculated what did they talk about? Their post-war accounts of the meeting differ, leaving many to question Heisenberg's true motive.

According to Heisenberg's own account, they take a walk in the park, you know, away from any prying ears. And what he cryptically tries to tell Boar is that Germany is working on a nuclear weapon. Now, this is a real risk, this is high treason. Have this been found out he could have been killed? Years later, Heisenberg claimed he was trying to enlist Boer to aid in his own efforts to prevent the creation of nuclear weapons. But this was not what Boer recalled. He claimed the meeting took place in his office and the intent behind it was radically different. Boer's response was, I don't remember any of that.

What I remember is you came and said, Germany is going to win the war. we needed to cooperate with the German authorities in Copenhagen. Whatever the truth of the matter, this meeting likely played a part in accelerating the USA's nuclear weapons program, the Manhattan Project. In 1943, Niels Bohr flees, Denmark ends up in the U.S. There, he tells his colleagues, the Germans are working in an atomic bomb, Heisenberg is working on it, And Boer tells them the message he thought he got from Heisenberg that Germany will win the war with nuclear weapons. In light of a groundbreaking discovery made in 1938 in Nazi Germany, this would have been no idle threat.

A nucleus of uranium 235 or plutonium absorbs the neutron. It then distorts like a liquid drop. Eventually, it splits into two or three additional neutrons. These are new elements and a great deal of energy. So one fission can become two, four, sixteen, two fifty six. Now if you slow this process down, you can produce heat and electricity. But if you don't slow it down and you have enough of a critical mass, this is the heart of an atomic bomb.

of this discovery spread like wildfire across the international scientific community. This was a groundbreaking discovery because when it became known, many physicists understood that this immense source of energy could be used as a weapon, because the destruction they reckoned would be absolutely colossal. After the discovery of nuclear fission, isolated scientists wrote to German officials saying there's a potential for a new weapon here. The same was happening in America. Albert Einstein, who had fled Nazi Germany, wrote to President Roosevelt to warn him

about the potential of a nuclear bomb. By the summer of 1939 in Germany, all research reports were classified. Army officials started recruiting the top scientists to work on military applications of nuclear fission. At this point, Werner Heisenberg became a crucial player in the Nazi war effort. He was a genius. He was a German scientist living at the top of his game in Nazi Germany.

He was well respected. He was constantly being invited to conferences. He was publishing papers. He was really immersed in the word of physics, and eventually politics kind of pulled him out of that. Born in 1901, into a family of academics, Werner Heisenberg's potential was clear to see from a young age. Heisenberg excelled in science and maths and even music from the word go as a child. And what he does is to constantly compete against his brother, who's only a year older than him. There is one part which is also kind of a constant in Heisenberg's life, just being competitive.

So he's often trying to be the best. At the age of 26, while at Gerdingen University, he revolutionized the world of physics with his principle of uncertainty. He later received a Nobel Prize. Heisenberg's life during the 1920s must have been incredibly intellectually stimulating. During his time here, he met Einstein and walked with Einstein. through the streets of the town. He met Niels Bohr

and established a lifelong friendship with him. He's an absolutely sort of focal point, a reference, if you like, in the world of science and physics during what is now known as the Golden Age of Physics in Germany. It's this time at the beginning of the 20th century where there were these huge scientific leaps forward.

But outside the world of physics, Germany was troubled, and a new radical party was right. rising to power, the National Socialist German Workers Party, led by Hitler. I think people of Heisenberg's generation, those born in very early years of the 20th century, were ripe for indoctrination by Nazism. I don't think Werner Heisenberg personally was. I think he was, if anything, a pure scientist. He was utterly absorbed in his work. Heisenberg was apolitical. He was not concerned with.

politics. He did not pay much attention to the Nazis until they came into power and started doing extreme things. Almost immediately, Hitler began introducing laws targeting Jewish people, and Heisenberg saw the devastation this wrought on the physics community. In total, 20% to 25% of the academic staff was dismissed. of them in the first period of 1933. This is devastating for the physics community. What had been an incredible momentum in atomic physics

is halted almost by the immigration of these physicists to other parts of the world. As Jewish professors left Germany one by one, Heisenberg pleaded with them to stay, arguing that the situation would get better. get better. Now, we now know that this was a very naive reaction, but it shows that Heisenberg was deeply affected by it, personally affected by it, but also that he really didn't believe that Jews would have to leave Germany forever. He thought this was just a wave of unpleasantness

that would settle down. But as things progressed for the worse, the German scientific community began to spread across the world, and those who were once friends would say, soon be working for enemy states. The beneficiaries of that were countries like France, England, the United States. This decimated the physics community. Heisenberg sees that happening. Heisenberg was powerless, and it wasn't long before he, too, became a target of Nazi ideological oppression.

An article from Das Schwarzakor, which is an organ of the SS, entitled Viseu, the Uden in Dervesenschaft, white Jews in the sciences. Written by an older physicist named Johannes Stark, it was a violent attack spurred on by jealousy of Heisenberg's career. The article is a diatribe against Werner Heisenberg, and it's devastating for him. The article explains that being Jewish is not only those who are of the Jewish religion or of the Jewish descent, but also individuals

who promulgate Jewish theories such as relativity theory by Albert Einstein or who have within their company Jewish citizens, of which Heisenberg is one. This was a masterpiece of character assassination in the Nazi regime. Stark, in addition here, calls Verna Heisenberg

not only a white Jew, but what he calls de Ossetsky de Physique. Now, Kaffin Ossetsky was a journalist who everyone knew was imprisoned in a concentration camp. So to be called the Ossetsky of physics was essentially saying Heisenberg belongs in a concentration camp. In Hitler's fanatical regime, such accusations could have grave consequences.

He couldn't sleep. He had dreams that, SS officers come to his slatter. How does Heisenberg respond? He went on the offensive to defend himself. And here, chance enters the history. Heisenberg was really quite lucky. His mother was an acquaintance of Himmler's mother. And that connection probably saved Heisenberg.

Himmler is in 1938, one of the three, four, five central figures of Nazi Germany. The most important is, of course, Adolfs, Hitler, and then when you look around a power system at this stage, can argue that Heinrich Himmler is, so to speak, a third of this group of four. Heisenberg had the opportunity to appeal directly to the head of the SS. Eisenberg gave the letter to his mother. His mother gave it to Himmler's mother. This was not timid. This was not meek. This was a demand. I refused to let people. call me this way. Himmler ordered an investigation into the matter. Heisenberg repeatedly traveled to

the Gestapo headquarters in Berlin for long interrogations. This was extremely stressful and distressing. His prestige worldwide meant he had the opportunity to flee abroad. Yet despite the attacks against him, he chose to stay and sided with the Nazis. Why on earth is he not taking the opportunity to leave? Heisenberg was constantly compromising his own position in the Reich in order to remain in Germany. He loved Germany. He did not want to leave.

Eventually, after a year-long investigation, Himmler cleared Heisenberg of the allegations. The SS leader had spotted Heisenberg's potential. With the war on the horizon, Germany could not lose. its top physicist. Hitler uses this phrase, which in German says, literally, we can't afford to kill this man. He wants to work with us.

We need him. September 1939, Germany has invaded Poland. The war in Europe has begun. Hitler's ambition was clear. He wanted to dominate the continent. To do this, he'd need powerful weapons. Army officials immediately created the Uranvarine, the Uranium Club. The Uranvarine or Uranium Club was the beginning of Germany's nuclear program.

Physicists assembled in order to begin the work of seeing whether fission could work for a nuclear bomb. Heisenberg was quickly recruited to take on a leading role in the role of the military Heisenberg was quickly recruited to take on a leading role in Germany's nuclear research. Essentially, he goes from being this kind of pariah to being the most important man in German science. Heisenberg's invitation to work on the nuclear project was for him a way to ensure the relevance of nuclear physics to the Reich. So far as I can see, there was very little introspection of creating weapons for the Reich. Heisenberg's first contribution to the uranium project was he works out the possibilities of controlling chain reactions in what he called a uranium machine, what today we'd call a nuclear reactor.

But to build Heisenberg's working reactor, they needed a substance vital to the process, heavy water, and there was only one place it could be sourced. The main supplier of heavy water in the world, but it was on the order a tiny amounts, was a power plant complex in Norway, called the Norse Kedro. The German was not interested in power plant itself, but they were interested in these cells. This is the eye concentration cells, which was used in the last steps of the heavy water production. Discovered a few years earlier, heavy water is found in normal water. but only in microscopic quantities.

And the process of extracting it is extremely difficult. They used brute force and massive amounts of electricity, essentially repeatedly boiling the water to separate the heavy water from regular water. Heavy water looks like, tastes like, and smells like ordinary water, but it's 10% heavier. And that is because it contains heavy hydrogen instead of common hydrogen. common hydrogen. If you water a flower with heavy water instead of normal water,

it will grow slower. Heavy water could slow down the neutrons produced by nuclear fission and thereby control the chain reaction. And it became crucial to Germany's nuclear research program. After Norway was invaded in 1940, the Nazis had complete control over the world's main source. The fact that the Germans are interested in heavy water, which has no other obvious military application, it very much frightened allied officials and allied scientists. It's essentially saying we are working on an atomic bomb. In time, the Allies would have to react. So Vermeck becomes this center of intrigue and the center of, okay, we don't know exactly what's going on in there, but whatever is going on, we need to destroy it.

Back in Germany, Heisenberg and his team of scientists were progressing on their secret research. He's certainly participating in advancing the use of nuclear fission to create what he called a uranium machine. But when you look at what Heisenberg was doing during the period 1939 to 1945, he is not devoting all of his energy to this project. He is still maintaining his activities at the university. Beginning again in 1940, he begins to receive many different invitations to travel abroad and give popular lectures on science. Heisenberg was renowned internationally. As such, he was sent across Nazi territories to promote German culture abroad. Heisenberg was supposed to give talks, have a couple of conference and the scientists at Niels Bohr's Institute were invited.

And it would have been open public collaboration with the Germans in Copenhagen. And Bohr and his colleagues refused to go. Heisenberg urged Danish colleagues, you should cooperate with the Germans. This disturbed Boer very much. Denmark was under occupation, but Heisenberg couldn't recognize the position that left him in. Whatever his feelings on the matter, he appeared as the scientific face of the regime. And this brought the attention of the Allies. These foreign lectures were ambivalent because outside of Germany, everyone perceived him

as a representative of Nazism. This was inevitable. He may have made a distinction in his own mind, I'm representing Germany not Nazi But his colleagues in occupied countries could not see that distinction. Heisenberg invariably said things that disturbed them. He invariably repeated the propaganda line of the German government. He defended the German war effort and he said, Germany should win the war.

But he never indults in anti-Semitism. And that's striking because it was so easy to to opportunistically use this language for one's benefit in the Third Reich. But in the end, Heisenberg got on well with leading Nazis because he was willing to work with them on things they considered important. His complex relationship to the state was difficult to understand for his foreign colleagues. But within the context of the war, Boer was convinced Heisenberg was committed to the Nazi effort. And it was a worrying state of affairs for the Allies.

Fear of a German atomic bomb was mounting. By 1943, the United States believed that Germany was making some progress on atomic science and perhaps building their own bomb. Determined to beat the Germans to it, the U.S. government created the top secret Manhattan Project. The race had begun. It was a massive international project. The three main centers in the United States were Oak Ridge, Tennessee, Los Alamos, New Mexico, and the Hanford, Washington.

They knew of the potential of nuclear power. They recruited scientists from all over Europe as well as America itself to work on this secret project. They had basically a blank check from Congress. They needed money. Congress was not allowed to ask what for. They just had to give it to them. Over 120,000 to 130,000 people worked on this project. There is awareness that the first people to create this new kind of weapon, they are going to have an absolute advantage in this war.

And so it was incredibly important to the Allies to do whatever they could to try to stop the Nazis from progressing. The Allies targeted key locations, and Vermeork was crucial to the German atomic program. But two years of aerial bombing missions had failed to have a significant impact on heavy water production. In the winter of 1943, Allied leaders decided on a new approach. They find out that actually just trying to kind of bomb the outside of the plant

is actually not going to help very much, because what they figure out is where a lot of the heavy water is being dealt with is actually underground. The only solution was to destroy the plant from the inside. The Nazis are then very aware of the fact that actually this is a place of interest for the Allies, which directly feeds into how difficult that final sabotage mission is going to be. In February 1943, Operation Gunnorside was launched. Nine saboteurs were parachuted into the Norwegian Mountains.

Their mission was to infiltrate the plant. They managed to make their way into the building without being seen by the United. the patrolling guards. They crawled over the pipes and jumped down on the floor in the room beneath where the heavy water cells were placed. The mission was to place charges on each the cells and blow them up. Working against the clock, detonators were placed on the 18 heavy water cells. By the time the Nazi guards rushed to the site of the explosion, the saboteurs were gone.

and the heavy water cells had been destroyed. To what extent did it actually stop the Nazi atomic program? It certainly slowed down the progress of the program at that particular time. This was a setback for Heisenberg and his team of scientists in Berlin. But the Allies were not just targeting production facilities. They were also targeting key individuals. The United States were determined to stop. those German scientists, either go and find them, capture them, or kill them if necessary.

Their main focus was Heisenberg. Now, according to some accounts, they got some intelligence. Heisenberg was giving a lecture in Zurich. So what they did is that they sent a spy, someone who could speak German. The name of the spy was Mo Berg, a former baseball star, with a knack for languages and an interest in physics. On the 18th of December, 1944, Berg actually goes to that lecture, and in his pocket, he's got a pistol. And he had very specific orders. If there was an indication that the Nazis were close to building a nuclear weapon, he was to shoot Heisenberg.

Heisenberg doesn't say anything about a bomb, doesn't say anything about building a weapon. Moberg then gets himself invited to a dinner party, where he gets to sit at a bomb. and listen and ask more questions. He did such a good job of playing his role that Heisenberg actually thought he was an SS spy, checking to make sure he wasn't telling any state secrets. Heisenberg was unaware he'd had a lucky escape. And for now, the Allies remained in the dark

about the progress of the German nuclear program. In early 1945, the end was near for nine. Nazi Germany. From the West, despite some harrowing battles and the harsh winter conditions, the Allies progressed further into Germany. From the East, the Soviets were closing in on Hitler and his army. But as the Allies gained territory, the focus was shifting. This understanding that there's going to be tension or conflict between the United States and the Soviet Union really intensifies the need to control German technology. So all of a sudden you have a race to see who can acquire the most territory and who can save the most scientists for their own side.

As part of the Manhattan Project, a scientific intelligence gathering mission called the Alsos mission was created and followed immediately behind the advancing allied armies. Their tasks searched for evidence of a German atomic bomb project and if necessary neutralize it. After making their way across Europe, the Alsos mission progressed into Germany, capturing scientists and nuclear material along the way. But they were after a bigger prize. The Alsace mission considered Werner Heisenberg prisoner number one. He absolutely had to be gotten in order to find out what the Germans had done, how far they had worked on their atomic bomb project.

He had to move from place to place. The scientists in Germany were not secure in the work that they did. They had bombing, they had invasions, they had the actual war was in their space. Secret Reports located him near a place called Heigrlach. Heigurlach is a small town in southern Germany. It's in a valley with a river running through it. And it's got cliffs all around it. So it's very secure and very safe.

hard to get into. The Alsos people entered Hegeloch from Hoab over the hill. The Alsos team consisted of maybe 30 to 40 people. It was a very small team with trucks and jeeps, no tanks or big weapons. In a hidden beer cellar carved into the side of a cliff, they found what they were after. secret nuclear laboratory. Research here at Hegeloff began only at the beginning of 1945, when work was carried out on a nuclear reactor. The goal was to prove that a chain reaction in a nuclear reactor was possible.

They worked here with a total of over 600 uranium belts. The uranium belts were embedded in the inner area. the inner area, then heavy water was poured in as a moderator. This was supposed to start a chain reaction. When the Alsos mission arrived, it appeared as if the lab had been raided. What they found was just a covered cauldron, with only the outer part of the reactor inside. Just days before, the German scientists had dismantled the reactor to keep their work secret from the enemy. The Americans could not risk leaving empty-handed.

They searched the area to identify and round up the remaining scientists who cooperated. With the help of the German scientists, they found the buried uranium, the hidden heavy water, they found the scientific reports. But what they essentially found was that this was an incomparably small, smaller, tinier scale than the American Manhattan Project, that it was simply not comparable. And so the idea that there could be any threat of a German atomic bomb was absurd. They had these ideas and these fears

that this great German scientist was making these very threatening advances, and it was just so underwhelming to find this very small reactor. While the fear of the Nazis gaining access to an atomic bomb had driven the Allies' own efforts, the reality was that Hitler had missed his opportunity a few years before. If you want to compare the German and the American atomic bomb projects, the turning point is summer-fall of 1942. Late spring, in 1942, you could make the case that the two sides are pretty comparable.

Hitler's failed military operations in the East had weakened Germany. The change in fortunes of the war had a profound immediate effect on the uranium project. Army ordinance asked the scientists, when can we expect these weapons? The scientists responded, nuclear weapons are feasible. It's unlikely that it can be done during the war. As a result, funding for the project was capped. And despite the fears of the Allies, it never went further than a theoretical program. Very many leading Nazis all spoke about these fantastic new weapons that would turn the tide,

win the war for Germany. The irony is that about the only wonder weapon that Hitler didn't talk about and didn't really pay any attention to was the atomic bomb. If I somebody had said to Hitler, my infurer, I have, of course, got the power to unleash the forces of nature in a nuclear blast. With this weapon, we can win the war. If he had been that sort of man, then the war might have had a completely different outcome. But he wasn't, fortunately. The threat of a German bomb was gone.

But the Allies still needed to locate their prime target. Heisenberg, in quite dramatic fashion, in the last days of the war, rides on his bicycle across war-torn southern Bavaria. to be with his family. He manages to reach his family. And he's only there a day or two. And suddenly American soldiers burst into his house. At the same time, there are SS men outside his house,

and there's a firefighter. Eventually, the Americans dispersed the German soldiers and got their hands on Heisenberg. He had to be arrested because they were afraid that the Russians would get him. Heisenberg and nine other scientists were brought to England and imprisoned in a safe house called Farm Hall. They had three square meals a day. They were allowed to play chess.

The conditions at Farm Hall were pretty cushy in comparison to prison camp. For months, the captives were unaware that the house was bugged. All of their conversations were recorded in the hope of uncovering more secrets about the Nazi nuclear project. The United States was keen to learn where the Germans were at because this was the American motivation for building the bombs in the first place. The Allies were also intrigued to see the scientists' response to the news of the Hiroshima bombing. Their reaction was unexpected. They were shocked. In fact, they were awed at the production of a bomb. Perhaps the Germans suddenly realized something they hadn't before.

They had been in a race against the Americans to build a nuclear weapon, and they had lost. I think if you study Heisenberg, if you read about him, and you read about what other scientists said about him, he was very smart. He was very competitive, too, and I think a bit arrogant is how he comes across. Heisenberg and the other scientists at Farm Hall were now faced with a dilemma. They had worked on a weapon of mass destruction for the perpetrator. of the Holocaust, and they needed to protect their reputations, both at home and abroad. That's not a particularly comfortable situation to be in.

So how do you handle this issue? You can't just say we sabotage the work, that would be betraying Germany. As a patriot, Heisenberg was unwilling to be seen as a traitor, which created another dilemma. You can't just say, well, we're in a traitor. well, we couldn't figure it out. That makes you look incompetent.

So by looking at the future like that, they begin to construct a narrative, a moral narrative, an outrageous one in most people's view. You begin with an accurate statement. It was not possible for Germany to make nuclear weapons during the war. You then bring in the legend of Copenhagen. and say that we traveled to Denmark in order to enlist the help of Niels Bohr

so that we could forestall the creation of all nuclear weapons. We wanted to save the world from nuclear weapons, not just stop the German ones. That's malarkey. That's complete malarkey. I mean, they're trying to save their post-war lives. For me, what's really interesting with Heisenberg is that he, he's always forced to find a way through a complicated situation. And he was very successful in not being too clear and too open.

I think he just lost and it's much easier to admit that you were actually the good guy trying to save the world than it is to admit that the other side won. After months in captivity, the scientists were finally released, and Heisenberg returned to Göttingen. He and his colleagues author what is known as the Göttingen Manifesto. They commit themselves to never working on nuclear weapons again. He's finally coming to terms with some of the moral questions that he should have raised during his time with the German atomic bomb project.

Perhaps Heisenberg was aware that he has helped to set the wheels in motion. The race to build the atomic bomb absolutely shaped the history of the world after this war. The atom bomb actually was the beginning of a race to develop deadlier and deadlier and deadlier weapons.

To this day, the United States of America is the only country to have used nuclear weapons in war. but the latent threat has been ongoing for decades across the world. The nuclear legacy of the Second World War is a war where we're in possession of the means of the destruction of humanity. We still have 14,000 nuclear weapons on the face of the earth, most of them in the hands of the United States and Russia.

Remember, the five permanent members of the Security Council of the UN are the original five possessors of nuclear weapons. They have a privileged position within the United Nations. Germany never developed atomic weapons. Although they hadn't built a working nuclear reactor in time for the war, Heisenberg and his colleagues had actively participated in driving the world into the nuclear era. Without the German-Ewanian project, There's no American atomic bomb, there's no nuclear arms race right after 1945.

The world would have been a very different place. Unexplored catacombs buried beneath the city, a crumbling castle perched on a mountain peak, a top secret government bunker, a cursed mansion cloaked in legend. I'm Sasha Auerbach. Join me in Tom Ward every Wednesday and Sunday as we reveal the mysteries and histories behind these abandoned places and ask, where did everyone go? We'll hear from Sasha, who knows the history the best. In fact, there's a very famous book by a chap named Marcus Rediker called The Many-Headed Hydra,

and he talks about pirate ships as an experiment in radical democracy. And me, who knows nothing, aeronautical scientists can't quite explain it. And they say, we don't actually know how it gets up there. How it stays up? You're just not good at a science. No, there are explanations? There are explanations. It's just plain physics.

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