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This is the BBC. This podcast is supported by advertising outside the UK. Sweaty palms. Even for one of America's leading economists, a meeting in the Oval Office with the president himself must be pretty scary.
The economist is called Alexander Sack's, a month ago, Sachs got a call from a fellow European economist in the United States asking for a favor.
No stranger to the Oval Office and certainly no stranger to Franklin Delano Roosevelt, Sax's less confident than usual. He's usually here to talk economics, but today he has another subject altogether to lay before the president. But the president has other things on his mind. Less than a fortnight ago, Germany invaded Poland, a war with unthinkable, destructive potential is underway in Europe, Sachs reads from a report by a little known immigrant Hungarian physicist by the name of Leo Salade that, if they're honest, doesn't really make much sense to either of them.
Roosevelt has other things to do. Today's topic of neutrons and atoms and energy falls on deaf ears. He ushers sacks along. It looks like nothing will come of this meeting. But then something changes as Sacks packs up his things and heads out of the door. The president, perhaps feeling he's been a little harsh on his old friend, invites him back for coffee the next morning. There are some moments that at the time seem totally inconsequential. But they go on to change the world.
This is one of those moments. My name is Emily Strasser from the BBC World Service. This is the bomb. Episode three, The Einstein Letter. Leo Szilard can't sleep in his mind's eye, he can see what the world will become. News from across the Atlantic has got him worried. In Nazi Germany, scientists he knows former colleagues have proved something. He spent six years trying to figure out. He knows what the consequences could be. He knows that nuclear war is no longer a fiction.
In his hotel room, dark and alone, Leo Szilard knows he has to do something. He knows he has to warn somebody. He knows he needs an ally now more than ever.
But he also knows that nobody will listen to him for the past few years, he struggled to have scientists, politicians and army commanders take him seriously. He needs a new plan. He needs a new ally.
This is Cynthia Kelley. The physicist world is electrified by the news of vision of the uranium 1939 January, the news that a group of scientists working in Germany have split an atom using neutrons. The process, called fission to scientists, come from Europe to the United States and announce the news to a conference of theoretical physicists at the George Washington University in Washington, D.C.. After hearing about a vision of uranium, a dozen physicists immediately go to the Carnegie Institution of Science to replicate the experiment.
Zijlaard was there half a decade ago.
Salade had imagined exactly this on a street corner in London. Now, before his eyes, he's seeing his vision come to life.
He had been worrying about this for so long, and it really caught the other scientists by surprise.
It's a lot has been proven right. The other scientists in the room had doubted that this was even possible. And disturbingly, the very people who proved it right are in Berlin. There is a lot Zijlaard does not know, but he fears that the Nazis may be further ahead in atomic research than anybody else.
A few weeks after the news of fission is announced in Washington, an article appears in The New York Times. Enrico Fermi, friend and colleague of Leo Szilard, is asked if the people of the world should be worried about this new scientific discovery. He dismisses it, nobody will be able to use vision, he says, for commercial or military purposes for at least 25 years, possibly even 50 years. And he really believes that it's far fetched.
The stuff, quite literally, of science fiction fiction splits an atom with neutrons, which releases energy. That's as far as it goes. William Kleinwort, what Leo Szilard thinks he can prove is that if you can get an unstable atom to fission, it would release more neutrons. Those neutrons would then split other unstable atoms, releasing more neutrons. And on and on it goes.
If Salade can get an unstable atom to fission, he thinks other unstable atoms around it will fission to those atoms will set one another off uncontrollably, a chain reaction that releases an unthinkable amount of energy.
Salade needs answers, so he heads back to the lab at Columbia University in the spring of 1939, salade teams up with Walter Zenn.
Salaat isn't a great experimentalist. He's clumsy and impatient. Walter Zendo is at home in a laboratory and an expert at rigging brand new and unlikely experiments.
ZENN sets everything up on campus. They have an oscilloscope that looks like a early TV and they're looking for flashes of light that will show neutrons are released of other neutrons bombard the uranium atom. They hook up their equipment and they start the neutron source. Nothing happens then then notices the monitor isn't plugged in, he plugs it in, they wait anxiously as the picture tube heats up and they can see the neutrons tracing across the screen.
The flashes are mesmerizing and they keep coming. Neutrons impacting atoms and releasing more neutrons. One step closer to what he did in the six years before in London, one step closer to a nuclear chain reaction the world Salade later wrote was headed for greif. I guess we haven't talked about heavy water yet. Nestled in the Norwegian mountains by a town called Vemork, cradled in a bluff by a powerful waterfall, is an electrochemical plant, but soon becomes clear to the scientists.
Trying to create a chain reaction is that neutrons being released from atoms are released way too fast. They find the atoms are more likely to absorb a neutron whizzing by if it's going slow. So how do you slow down neutrons, water? It turns out it works pretty well, a little too well, though. Water actually absorbs so many neutrons and makes it ineffective and a chain reaction. So how about changing water? Water is generally made from two hydrogen atoms and a single oxygenated H2O.
But instead of those hydrogen atoms, you use an isotope of hydrogen where each of its atoms contain an extra neutron. You make something similar but different.
That extra neutron makes it heavy water get it messing with something so fundamental to human life in order to create a bomb capable of wiping out human life on a massive scale.
There's an irony in that. Heavy water is tough to produce, the only way Germans can think to do it is to burn a lot of coal, but they can't do that in wartime. They simply don't have enough natural resources. So the Nazi government send representatives to Vemork, Norway. Here, they're producing heavy water as a byproduct of their normal work. The Germans offer to buy up all the existing supplies of heavy water at an impressive price, urging the plant to increase production.
But the Norwegians are suspicious. They refuse to sell and reject requests to increase production. They may not know what Hitler's plans are, but they have no interest in being part of them. Then a French Secret Service team approaches the plant and warns the Norwegians of the potential military purpose of their chemical byproduct. The Norwegians insist that the French take the entire stock without payment, but the Germans find out. Twenty six cans of heavy water are smuggled out of Vemork by the dark of night.
It's a tense operation. The Germans are primed for action, their fighter planes are ready and waiting, they target the aircraft. The French officers had been seen to board and pressure it, forcing it down for inspection. The Nazi officers board only to make a frustrating discovery. The plane is a decoy. There's no heavy water on board. The water is actually being transported by rail, the entire supply successfully makes it to Paris, where a scientific team urgently begins experiments.
I was born in Hiroshima and stayed there until I finished university. I lived during 15 years of war, so throughout my childhood that was the only thing I knew. There was some good times and happy times. Food was not so scarce. And with friends and relatives and families, we had dinner parties and going to the swimming, visiting among the friends and relatives. Actually, I have a lot of happy memories. All of a sudden everything became so limited and what I miss most was sugar.
We couldn't have the candy and that was hard for a young child growing up. And life got harsher and harder. Each month and toward the end, we were almost starving. When high school and the university boys were recruited into the army, I think personally, deep inside their heart, they were sad to leave their families and homes, but with a grin and a happy look. And they said, well, don't worry about me, I'll be back soon.
What they felt inside, what they acted as they were, two different things. People just couldn't raise questions. Yeah, that was the kind of life. I remember. In nineteen thirty nine, war is looming in the months since his neutron experiment, Salade has been working with Enrico Fermi and they've developed the plans for a working nuclear reactor. But they still need to slow those neutrons down. And the only heavy water in the world is still in a Norwegian electro chemical plant.
So instead of heavy water, they think they can use pure graphite to slow down the neutrons and cause a chain reaction.
If they're right, they have a solid chance to get ahead of the Nazis.
Salade fears, the bomb, but he fears a Nazi bomb. Or imagine the devastation. Imagine the oppression. What might it mean for people like him? A chain reaction is in motion. He believes there will be a bomb. And so he's come to a simple conclusion. The Americans must develop the bomb before the Germans. He must convince them to do it. He must offer them the ultimate power. So he thinks who is the one scientist that the most powerful people in the world will not ignore?
There's one obvious candidate.
It's been nearly 20 years since Leo Szilard first met Albert Einstein in a lecture theater in Berlin. It's been 15 years since they would regularly walk home together at the end of each day, sharing ideas about physics, philosophy and politics. Now, they're both exiles in America and they live just a few miles apart. Along with his friend, colleague and fellow Hungarian Eugene Vikner, Salade decides to go and see Einstein.
Yeah, well, Salade knew that Einstein was most of the time in Princeton, but when they called his office said, oh, no, the professor is out on Long Island at the college of a friend.
So that's where Salade goes to. Hungarians drive from New York City to visit him in the little village of Peconic. It is July 12th, 1939.
Cynthia Kelly, president and founder of the Atomic Heritage Foundation.
And you imagine the two of them define the village and no idea where the cottage is.
The cottage is up the hill from the water and it's is surrounded by trees.
Einstein doesn't know they're coming, but welcomed them in nonetheless.
And so they're three men set, three scientists talking about nuclear physics, politics and a discovery that is about to change the world. One salade explains a nuclear chain reaction to Einstein and explains that he and Fermi have been designing and conducting experiments. Einstein is amazed and alarmed. I haven't thought of that at all, is his first answer.
The science is exciting to Einstein. Fission is equals. Mzee squared in action, being a refugee from Nazi Germany and being a committed pacifist and being a politically aware person. He sees right away the potential for nuclear weapons in the hands of Germans.
Einstein agrees that the situation is urgent. With Germany poised for war, he agrees to sign a letter to Roosevelt to warn him about the German progress in later life.
Einstein calls his vocal support for salade that day the one great mistake of his life. But whether they like it or not, they're on a quiet summer's day in a modest American house. In a typical American town, three men have changed the course of human history. And so, with the Einstein letter in hand, Leo Szilard sets off back to New York City. Now all they've got to do is get the letter to the president. And that leads us back to Alexander Sack's.
Salade is the consummate networker after he finished his Ph.D. in physics in Berlin. He wanted to study economics. He knew an economist from Berlin who knew Alexander Sachs.
Who was a rather famous economist, a Wall Street banker and an adviser to President Franklin Roosevelt. He approached Sachs to say, would you deliver a message to the president?
Sachs's first meeting with the president did not go well. He bewildered the president with all the talk of science and energy and government involvement.
But he got an invite to breakfast the next morning and now he has a second chance to get the most powerful man in the world to understand the looming danger.
Several times he left the hotel in the middle of the night to walk around the nearby park. Finally, he came up with a plan.
SAC's walks in and greets Roosevelt, who's sitting at the breakfast table in his wheelchair. Salade has stressed to SAC's just how important the message he's carrying. Is he stressed or the consequences might be if he fails. But Sachs knows from their last encounter that science won't be the way to win this president around. So he tells them a story. It's in the middle of the Napoleonic wars, a young American inventor comes to Napoleon and offers to build a fleet of steamships that he said would let him land in England, whatever the winds were, ships without sails.
This seemed so impossible that Napoleon sent Robert Fulton, the inventor, away, as well as a steamboat.
Felton was the man who built the first submarine and the earliest torpedoes. The president remained silent for several minutes. Then he ordered his servant to fetch a bottle of old French brandy from Napoleon's time.
Reminder, it's breakfast time. Alex, what you are after is to see that the Nazis don't blow us up. Precisely. Roosevelt gets it. The story of Fulton and Napoleon might be what got the president's attention, but it was Albert Einstein's letter authored by Leo Zijlaard that persuades Franklin Delano Roosevelt. So this is it.
The moment when the most powerful person in the world takes Leo Szilard seriously and everything changes. The bomb from the BBC World Service is hashtag the bomb on social media, the show was presented by me.
Emily Strasser, the producer is Glenn Tansley. Our writer was Acey Smith and our scripts were edited by James Robinson. Title music was composed especially for us by Trevor Gorecki's. Our sound design is by Richard Gould at Skywalker Sound. The program was mixed by Lyndon Jones with additional sound elements by Eloise Wetmore, the production team is William Richards, Amelia Parker, Alice McKee and Amy Will. Our series editor is Martin Smith and are commissioning editor at the BBC World Service is Simon Pitts.
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