by Sam Kean
However satisfying it was to watch Bothe flail, Joliot—and Irène, who’d rejoined him in Paris—were having a miserable war. Paris was growing gloomier every week, with widespread shortages of everything. In this greatest culinary city in the world, people resorted to eating stray cats to fill their bellies, despite the risk of catching plague from the rodents the cats ate. The Nazis also seized all available fuel for their munitions plants. As a result Irène and Joliot couldn’t afford to heat their home, where temperatures sometimes hovered in the low thirties; a glass of water left on the nightstand would nearly have frozen. The cold in turn exacerbated the family’s poor health. Hélène had rubella; little Pierre had both rubella and mumps; and Irène, already suffering from consumption, was knocked flat with bronchitis and anemia. Despite this misery, she gamely tried to continue her research, even if it meant lying down while working, and she spent months at a stretch in sanatoriums. Just like her mother, she was losing some of her most productive years to ill health.
But ill health didn’t stop Irène from fighting the Germans in her own way. As mentioned earlier, upon fleeing Paris in 1940 she’d carried a lead-lined case containing the $100,000 gram of radium she’d inherited from her mother. Knowing the Germans coveted radium, she’d decided to stash it somewhere, but didn’t want to use a vault or a safe—the first places the Nazis would look for loot. So she risked storing it in an ordinary cellar in a town near Bordeaux—hoping that, like Poe’s purloined letter, the Germans would overlook it.
However clever this seemed at the time, Irène became increasingly uneasy as the war progressed. If the Germans caught wind of the radium’s location, they would seize it for their own nuclear research. On top of that, this was her scientific inheritance, and as a Curie woman she wouldn’t stand for the Germans stealing it. So in June 1941 she set out to recover her birthright.
Under normal circumstances Joliot would have accompanied her, but the Nazis were watching him too closely. A woman, on the other hand, wasn’t worth their notice, and when Irène requested permission to visit Bordeaux and salvage some “lab equipment,” the Nazis waved her and two assistants through. Irène still had to be sly: to justify her cover story, she grabbed some scientific instruments and other supplies while there. But amid these errands, she managed to slip into the cellar and recover the 130-pound case without attracting notice. She then had to smuggle everything back home on the train, enduring every German checkpoint. Arriving back in Paris, she found no cars available at the station, so despite her exhaustion she had to load the radium case and other equipment onto a horse cart and start pushing. “It was thus,” she recalled laconically, “that the radium was returned to the laboratory.” The Germans never suspected a thing.
Irène showed her mettle again later that month. On the morning of June 29 the Gestapo arrested Joliot, taking him by surprise over breakfast and hauling him down to their headquarters, an imposing stone building. His interrogators accused him of several crimes, including being a communist and stirring up student unrest. Thinking quickly, Irène ran off to find Wolfgang Gentner, the former assistant now running Joliot’s lab. She begged him to intercede. Rather bravely—he easily could have landed himself in jail—Gentner marched downtown and demanded Joliot’s release. He claimed that Joliot was doing vital military research, and that officials in Berlin would be furious. This was complete garbage: Joliot was in fact sabotaging Nazi research, as Gentner well knew. But the Gestapo guards, trembling at the mention of Berlin, quickly released him.
Despite this attempt to intimidate him, Joliot did join an underground communist cell shortly afterward to aid the French resistance. At first he merely passed on bits of scientific intel. As part of the wartime blackout, the windows at his institute had been painted over, so at night he would sneak into the labs of Bothe and others and read their secret reports. Over time this snooping gave way to riskier jobs, as he became a courier between different cells. He and other agents would rendezvous in theater lobbies, in dentists’ waiting rooms, even amid the fossils of the National Museum of Natural History, and whisper messages back and forth.
It would take the deaths of several colleagues to push Joliot into active resistance. One was a sixty-one-year-old physicist and longtime friend of Marie Curie. Like Joliot, he worked for an underground communist cell and had been helping to sneak downed British pilots into neutral Spain. (If shot down in France, British pilots were instructed to seek out either communists or Catholic priests, the most trustworthy foes of the Nazis.) The Gestapo eventually infiltrated the group, and the physicist was arrested and beaten to death the day before Christmas. When his widow claimed his body, his clothes were torn and covered with feces, and he had broken bones and scald marks on his skin—signs he’d been tortured. Joliot and Irène were horrified.
Then, in May 1942, four more scientist-communists, one of whom was publishing an anti-Nazi newspaper, were swept up and shot without trial. Jolted again, Joliot officially joined the French communist party and committed himself to resisting Nazi rule. Given that he had a family, this was not an easy decision. And although they’d always shared everything with each other before, he and Irène decided that he would tell her nothing of his resistance work, to protect her when the inevitable crackdown came.
In the meantime Joliot set about the work of an underground agent. For example, he helped stage a fake car accident involving Marie Curie’s former lover, Paul Langevin, who’d been in and out of Nazi prisons despite his advanced age. Joliot then swaddled Langevin in bandages to conceal his identity and got him across the border into Switzerland. Joliot also secured fake identity cards for Jews in hiding, passed along tips about impending raids, and, perhaps most importantly, smuggled weapons. A former assistant now worked in a police unit that investigated French sabotage against the Reich. His job involved impounding radios and guns and bomb parts seized in raids, for the purpose of destroying them. In reality, he packed everything into suitcases and smuggled it to Joliot, who redistributed the goods to the freedom fighters. Thanks to this recycling program the underground in Paris never lacked for arms or equipment.
More gravely, Joliot helped settle the score for his and Irène’s murdered colleagues. When the French underground caught traitors—double agents secretly working for the Nazis—Joliot reportedly made the final decision about whether to execute them. Just eight years earlier, he’d danced around his laboratory after discovering a new secret of nature. Now he was killing men after uncovering theirs. War had made a hard man of this once cheerful physicist.
CHAPTER 17
The Fire Heard ’Round the World
While nuclear science limped along in Allied nations, things in Germany were hopping by June 1942, when Werner Heisenberg ran the most sophisticated nuclear fission experiment the world had ever seen. Over the previous few months, Heisenberg had built three different Uranium Machines in Leipzig, each more powerful than the last. Most of them used a “sandwich” design with alternating layers of heavy water and uranium ore (which the Germans code-named “Preparation 38,” based on its chemical formula, U3O8). But for his newest reactor, L-IV, Heisenberg changed things up. Instead of flat layers, L-IV used four spherical shells, each one nested inside another. In addition, instead of using uranium ore, he swapped in pure, powdered uranium metal. (This powdered metal was kept separate from the heavy water by thin shells of aluminum, for reasons that will soon be clear.) Although just thirty-two inches across, the apparatus weighed three-quarters of a ton, and it generated so much heat that technicians kept it immersed in a tank of (normal) water at all times.
The L-IV experiment began when someone dropped a ball of radium and beryllium through a chimney into the innermost shell of heavy water. Radium emits alpha particles, which struck the beryllium atoms and dislodged neutrons. These neutrons plowed into the heavy water, slowed down, and induced fission reactions when they reached the first layer of uranium. These fissions released more neutrons, which again slowed down as they moved
outward and encountered the next layer of heavy water. Which of course caused still more fissions in the outermost layer of uranium. Because Heisenberg’s team knew roughly how many neutrons the radium-beryllium ball at the center released each second, they could measure the neutrons escaping the sphere’s surface and calculate a “neutron multiplication” factor, a measure of how many extra neutrons the setup produced. In June 1942 they got a multiplication of 13 percent—the first positive neutron production in history, and step one in a chain reaction. Shortly after this, Heisenberg reported the results of his experiment to several Nazi leaders, including Albert Speer.
Unfortunately for Heisenberg, a series of accidents soon destroyed the L-IV apparatus. Powdered uranium is pyrophoric, meaning it can react with the oxygen in the air and ignite spontaneously. (It’s a chemical reaction, mind you, not nuclear, but it’s still a doozy.) Heisenberg’s lab had learned this fact the hard way a few months earlier. An assistant had been spooning powdered uranium into a funnel to fill one of the shells. He suddenly heard a “dull thud.” He paused to listen, and a twelve-foot flame exploded out of the funnel, knocking him backward and scorching his hands. He tried smothering the fire with his coat, but a nearby box of uranium powder caught fire as well, and another assistant had to rush it outside and smother it with sand before evacuating the room. To the researchers’ horror, the metal was still smoldering a day later, so they dumped the box in a bucket of water—which quenched the fire, but taught them an unfortunate lesson.
The second accident unfolded more slowly, but the pyrotechnics proved even more spectacular. Heisenberg’s team normally kept the sphere in a tank of cool water, and one afternoon in late June an assistant noticed a stream of bubbles in the tank. He captured some and determined that they were hydrogen, a bad sign. Apparently a leak had developed in the sphere, and the uranium inside was stripping the H2 off the O and producing explosive gas. Around 3:15 p.m. the bubbles stopped, so they winched the sphere up to take a peek inside. The fellow assigned to remove the cover was the same hapless assistant who’d burned his hands before, and he had no better luck this time. As he unscrewed the cover he heard a hissing noise, an inrush of air. Two seconds of ominous silence followed—then another volcano, with burning uranium playing the part of lava. The poor fellow covered his head and ran.
The fun wasn’t over. Remembering the lesson from the first incident, the team decided to douse the burning uranium with water. This would cut off the flames’ oxygen supply and put the fire out. Unfortunately, while uranium powder can ignite in air, it can also react explosively with water. (It’s fun stuff.) Unaware of this, the assistants dunked the apparatus back into the tank and waited.
At this point Heisenberg ducked his head into the lab. Everything okay, boys? Yeah, chief, great. The place couldn’t have smelled good—burning metal has a distinct odor—but Heisenberg said okey-doke, and wandered off to teach an evening seminar.
In the middle of the seminar, around 6 p.m., an assistant interrupted with a knock. You might want to take a look at this, chief. Heisenberg ran back to find the tank of water seething with bubbles. Two assistants stood next to it, staring, wondering what to do. Suddenly the sphere shuddered, visibly bucking. Without even wasting time to yell, everyone dove for the hallway.
The sphere exploded with such force that a hundred metal rivets holding the aluminum shells together were ripped apart, shattering completely. The flames reached twenty feet high this time, licking the ceiling. The scientists ran for their lives, and the local fire brigade came roaring up a few minutes later. Despite their best efforts, the firefighters couldn’t put the inferno out, only confine it. The sphere continued to smolder for two full days afterward, forming what one witness called a “gurgling swamp” of singed metal and polluted water.
Still, because no one had died, the firefighters had a good laugh about the whole thing. One of them who knew Heisenberg slapped the physicist on the back and congratulated him on finally producing an “atomic explosion.”
Heisenberg had plans to transfer his lab to Berlin after the L-IV experiments, so the mishap provided a convenient stopping point. But no one could deny what he’d achieved in Leipzig: the first positive neutron multiplication in history, and arguably the first real, if small-scale, nuclear chain reaction.
Rumors of the accomplishment spread to other members of the Uranium Club, then throughout Germany. Scientists in neutral countries like Switzerland heard next, and they in turn told colleagues across the world. You can imagine what happened then. However precise they strive to be in their work, scientists are no less prone than laypeople to embellish hot gossip. And before long, several nuclear scientists were conflating the 13 percent neutron multiplication with the later reactor fire, as if some sort of atomic explosion really had taken place. Similarly, a few burned hands and some singed clothing metamorphosed into grave injuries.
By the time the scuttlebutt reached the United States, Werner Heisenberg had achieved a full-scale nuclear reaction in his lab, with the resulting deaths of several brilliant young physicists. And because the United States lacked any sort of scientific espionage program, officials had no way of determining the truth of this; as a result, they believed the falsehoods. One top scientist in Chicago, after sitting down and plotting out Germany’s apparent rate of progress, calculated that Hitler could have an atomic bomb in hand in six months. If nothing else, he reasoned, a working nuclear reactor would allow the Reich to mass-produce radioactive species for dirty bombs to attack European cities.
The rumors about the L-IV fire had two effects on the Allied nuclear community. First, American physicists looked at their own, so-far feeble attempts to build a bomb and grimaced. They simply couldn’t dillydally any longer. So in a scientific declaration of war, they founded the Manhattan Project on December 6, 1941—just hours before the raid on Pearl Harbor pulled the rest of the country into war. Second, officials began scheming about ways to strangle the Nazi atomic bomb program. One obvious way involved Werner Heisenberg: remove him from the project, and it would surely stumble. Another chokepoint was heavy water. The Nazis required it for their research, and there was only one firm in the world producing it at the time. A plan quickly emerged to reduce that number to zero.
CHAPTER 18
Off to War
Although he didn’t know it at the time, Joe Kennedy’s life took a deadly turn on May 15, 1942. That afternoon a British Spitfire returning from a reconnaissance run over the Baltic Sea passed by a small island off northern Germany. A photographer in the plane happened to glance down as they were crossing a cape called Peenemünde on the northern tip, and he noticed some circular embankments there. They seemed awfully large, so he snapped several pictures. A few days later, those pictures landed on the desks of British intelligence agents. The name Peenemünde was not unfamiliar to them: the Allied underground had recently passed along rumors that the Nazis were shipping expensive, high-end vacuum tubes there. But the circular embankments baffled the agents. They decided to expand surveillance of Peenemünde to figure out what was going on there.
If the British had only listened, a spy in Berlin had already told them exactly what was going on—and it was ominous indeed. In late September 1939, an aerodynamics expert named Wernher von Braun had gathered dozens of top scientists and engineers in Peenemünde for a conference. Von Braun would go on to become a legendary rocket scientist in the United States, the architect of the Apollo moon mission. Back then, he was just an ambitious twenty-seven-year-old Nazi engineer, and at the three-day conference—jokingly titled Der Tag der Weisheit (The Day of Wisdom)—he and his colleagues swapped ideas about several revolutionary new weapons.
The Day(s) of Wisdom were top secret, of course, but word of them soon trickled out to Paul Rosbaud, the publisher who’d rushed the first uranium fission paper into print to warn the Allies. Since then, he’d adopted a nom de guerre, the Griffin, and had become the top scientific spy in Axis territory. He channeled information about
all manner of topics to Allied agents, often by encoding messages in books whose printing he oversaw. After hearing about von Braun’s little conference, Rosbaud began gathering string about it. He was something of a scientific bon vivant, and would invite colleagues to lavish dinners with lovely wines. None had any idea they were betraying secrets. They didn’t even know their friend traded in secrets. They simply enjoyed his company and were happy to pass along bits of gossip about von Braun and the new rocket weapons at Peenemünde. Everyone agreed that the British were in for a hell of a surprise.
In a huge gamble, Rosbaud eventually snuck up to Peenemünde to poke around. Geographically, Peenemünde sits on an island near the present-day border between Germany and Poland. Part of it was once a beach resort; the rocket-testing grounds occupied the northern half. Although modest in size (around ten square miles), its shape stood out ominously on a map: it looked like the bald head of a wraith, its mouth gaping wide, screaming straight at London.
For ten days the Griffin haunted the woods around Peenemünde, watching and listening. The Nazis had restricted access to the island, but locals had seen strange vapor trails arching across the sky, followed by sudden explosions. Unbeknownst to them, they were watching the birth of the dreaded Vergeltungswaffen, or vengeance weapons, the V-1s and V-2s that would so terrorize London. At the end of World War I, the Treaty of Versailles had forbidden Germany from stockpiling certain weapons, and in a topsy-turvy way, the ban benefitted the German military in the long run, since it forced them to innovate and invent new ones. The V-weapons grew directly out of such programs. The V-1 was essentially a 2½-ton, 27-foot-long drone airplane packed with explosives. It proved difficult to aim, but had a crude autopilot to steer it toward its target. The V-2s were even bigger and badder, stretching 44 feet and weighing 14 tons. As the first true ballistic missiles, they didn’t fly so much as whoosh straight upward and kiss the edge of space before plummeting back down. Perhaps most frightening of all, because the V-2s moved at supersonic speeds, people never heard a thing before they smashed home. If you heard the explosion, you’d already survived.