chapter five

In Exile

1938

In 1938, Lise Meitner was spending her first Christmas holiday in Sweden. With her was her nephew Otto Robert Frisch, a scientist himself. She was excited to have him for company. The two shared similar interests and were alike in many aspects of their personality; he was one of the few family members with whom she could talk science. She didn’t like Sweden, with its icy-cold temperatures and the wetness and dreariness to which she awoke every morning—everything seemed duller to her, grayer than it had been in Berlin, and uglier than it had been in her native Vienna.

She also felt isolated, far away from home, from family and friends and colleagues, although she was happy to be alive and with people she knew. The only good thing about Sweden was the mail service. With a two-day delivery between Stockholm and Berlin, she could send letters to her longtime collaborator Otto Hahn and her other colleagues and feel as if she were still working with her old friends and had a finger on what was happening in the scientific world.

Frisch had arrived a day earlier than expected, eager to surprise his aunt. He knew she felt lonely in Sweden. She had become used to a certain lifestyle in Berlin, and even after several months, she was still unable to acclimate herself to her new surroundings. He knew that she would appreciate a visit from him and some familiar discussions.

He had always been impressed by his aunt and enjoyed his conversations with her. Whereas his aunt was a quiet and thoughtful woman—some would even say somber—Frisch was bright-eyed and eager, a friendly man who put everyone at ease. He had been working in Copenhagen at the Institute of Theoretical Physics under Niels Bohr, a job he enjoyed and a place he felt at home.

Lise knew Bohr very well. She first met him in 1920, when he visited Berlin to speak at the famous Wednesday colloquium. Not fully understanding his lecture, Lise and the younger physicists had invited him to lunch without the older professors. Bohr was charismatic and friendly, spending hours answering questions. She met him again a year or two later, when Bohr had invited her to Copenhagen to lecture at his new Institute for Theoretical Physics. Combining theory and experiments, Lise and Bohr had a similar approach to science, and they clicked. They talked “about everything under the sun,” and formed a lifelong friendship, strengthened by her regular return over the years to participate in Bohr’s renowned conferences.

Now, during the holidays, Lise listened to people talking about the latest babies being born and holiday meals being prepared. She felt detached, the same way she had as a young child when she discovered an insatiable love for learning, puzzles, and, science.

Despite her solitude, she knew she was lucky. Lise was Jewish by birth, which made her a target of the Nazi government in Germany. For the past five years, Jewish scientists had been fleeing Germany to escape Nazi persecution. Friends had managed to smuggle Lise out in July, but she had to leave behind almost thirty years of work in Berlin.

As she waited for her nephew to join her, Lise’s thoughts turned to Hahn, who was still working at the Kaiser Wilhelm Institute. His latest letter contained startling news of his experiments with Fritz Strassmann. She perused it again. Given Frisch’s work in nuclear physics, she knew he would be intrigued.

Otto Hahn had written to Lise Meitner looking for guidance, for an explanation that would put his puzzling results in a physics context. He was depending on her, just as he had always depended on her since they first teamed up in 1907.

By then Hahn had been researching radioactive substances for a year at the University of Berlin’s Chemistry Institute. Before Berlin, he had studied radioactivity at McGill University in Canada under noted physician Ernest Rutherford, who had codeveloped the theory that elements could disintegrate and transform into other elements. But back in Germany, radium research was so new that the organic chemists at the institute didn’t take his work seriously, and he had nobody to collaborate with. He was shunted off to the school’s old basement workshop to conduct his radiation experiments.

Hahn found the physicists at the university a bit friendlier and regularly attended the Wednesday physics colloquium. It was there that he had met Lise Meitner. She had recently moved from Vienna to attend the lectures of the theoretical physicist Dr. Max Planck and was looking to fill her free time doing experimental work. Knowing her interest in radioactivity, the director of the university’s Physics Institute had suggested she work with Hahn.

Close in age, the two young scientists liked each other immediately. Hahn’s informal demeanor made Lise feel comfortable asking questions, and Hahn was glad to find another scientist who shared his interest in radioactivity. Together, their different physics and chemistry backgrounds allowed them to conduct and analyze experiments they couldn’t accomplish on their own.

There was just one small glitch: Hahn worked for Emil Fischer, who ran the Chemistry Institute. Fischer did not like female students and scientists and forbade them from working in his laboratory. Hahn asked Fischer to make an exception for Lise. She would be an excellent addition to the institute, he told Fischer. She had the right background, which would enhance the institute’s status; Lise Meitner would be the physicist, while Otto Hahn would be the chemist. Fischer relented, saying that as long as Lise would agree to stay in the old basement workshop with the radiation equipment, she could work with Hahn. She was told that this would be only a temporary situation, but as it turned out, her stay in the basement extended to five years.

On occasion, when no one was looking, Lise would quietly leave her office and walk up the creaking staircase, down the corridor, and into the lecture halls. There she would huddle under the benches and for the next hour or two listen to the presentations. She yearned to sit with the rest of the male scientists, but it seemed like an unsurpassable barrier. When the lectures and presentations were over, she returned to the basement. It upset Lise that such attitudes persisted in a university setting.

Once a month, she made the trek to the post office to collect the money her family sent her, as her position at the university was unpaid. She supplemented her allowance with money from writing and translating scientific articles and lived frugally, often surviving on coffee and dry bread.

Her financial situation changed nominally when in 1912 Dr. Planck made her his assistant, her first paid academic post. The stipend was scant, but it came at the right time, because her father had died and her family was struggling to provide Lise with an allowance. At that same time, the new Kaiser Wilhelm Institute for Chemistry opened in Berlin. Otto Hahn was offered a salaried position in charge of radioactivity; Lise was invited to join him as an unpaid “guest.”

In her new lab, no one paid attention to the vapors that wafted from the large bowls of mercury left out in the open, or to the beads that fell from the bowls and became embedded in floorboards and cracks on the table. Mercury’s dangers were not known, or perhaps were simply ignored. The scabs that were forming on their fingertips were not thought to be associated with the mercury, and it was only when a member of their team died of carcinoma that the connection was made.

Soon after starting work in the laboratory, Lise began to experience headaches and terrible nausea. Oddly enough, on a visit to Austria to see her family, the symptoms disappeared. She did not connect her pain to the poisonous atmosphere that surrounded her, and credited the cure to the fact that in Austria she felt less stressed.

The environment at the Kaiser Wilhelm Institute suited Lise Meitner, and in 1934 she was eventually hired as an associate. Several years later she became a professor in charge of her own physics department. The study of radioactivity was rapidly leading to exciting discoveries, and the early 1930s proved to be fruitful years in atomic research. A major breakthrough occurred not in some dusty laboratory in Europe, but in the United States. It was in New York, in a laboratory headed by Dr. Harold C. Urey, that a group of physicists discovered deuterium, a stable isotope of hydrogen. Also called “heavy hydrogen,” it would have a great impact on atomic research. Then, in 1932, the neutron was discovered in England, followed two years later in France by the Joliot-Curies’ discovery of artificial radioactivity. This set Fermi to bombarding elements with neutrons, which led to the experiments in Berlin.

In Italy, Fermi was excited by this new discovery. He was thirty-one years old and had been waiting for something new to occupy his mind. When deuterium was discovered, he decided this would be the element he would “play with” the most. Fermi and his colleagues brought a list to the chemical shop of all the elements they needed to buy in order to bombard them. Fermi and his staff bombarded these elements with neutrons, and this included uranium.

Lise, like other scientists, kept tabs on all this activity. It was how research was conducted, how everyone worked. Everyone followed what everybody else was doing.

As the years passed, new elements were discovered by almost every scientist working in the field. And while in the laboratories across Europe work continued at a feverish pace, social concerns began to trickle in from the outside world.

Adolf Hitler became chancellor of Germany in 1933. Seen at first as a fringe figure of the radical far right, Hitler rose to power trading on people’s misery and fear during the worldwide economic depression and desperation of the previous few years. Through relentless propaganda and fiery rhetoric, Hitler and the Nazi Party blamed Jews, Communists, and a weak government for Germany’s woes, and hatred and violence toward Jews increased. Lise had picked up Hitler’s book, Mein Kampf, when it was first published. Not wanting to spend money on it, she thumbed through it while browsing in a bookshop and was shocked by its tone and anti-Jewish message. She quickly put it down, unable to digest its contents. Inside the laboratories, scientists moved on with their work.

By 1938, Lise Meitner and her group had managed to find nearly a dozen radioactive substances within uranium bombarded by neutrons. They were satisfied with their research and their work, and life would have progressed in a similar fashion if Germany had not annexed Austria in March of that year, introducing new regulations under which Jews now had to lead their lives. Although Lise had been living in Berlin for many years, she was an Austrian Jew, and so those new regulations applied to her.

The dark moods that had become widespread outside the laboratory began to worry the scientists, too. Lise read the daily newspapers and kept watch on the activities happening around the city and the country. Everywhere she looked, the news was grim. But Otto Hahn assured her that she had nothing to be concerned about. Why would she fear Adolf Hitler? he asked. She reminded him that aside from being Austrian, she was also Jewish. Although she had never hidden her background, she had not flaunted it, either. It was, her father had taught her, just part of her heritage. He had also taught her to reject the notion that she was inferior because of her Jewish blood. Yet now she was worried because of it—not everyone held the same beliefs that her father did.

Hahn didn’t think that Hitler’s new regime would last long. It would break apart soon enough, he thought, and no one would ever hear about that little man again. Hahn was so confident about this that Lise’s concerns seemed almost childish to him. He was preparing to leave the country for a semester of lectures at Cornell University, in Ithaca, New York, that would keep him in the United States for more than four months, and nothing she said seemed to bother him. He was looking forward to getting away and didn’t want anything to stop him. In fact, the possibility of postponing the trip never dawned on him.

But Lise felt afraid, and it seemed to her that after so many years of working together and their long friendship, Hahn was deserting her. She begged him to stay and help her through this difficult moment, to assist her in coming up with a plan of action. But he wouldn’t hear of it. Actually, he thought she had become very unreasonable and too emotional. It was unbecoming of her, a side of her personality that he had never seen before and that he didn’t appreciate. She was like all the others: too sensitive and dramatic, something he had not expected from her.

Six weeks after Hahn left for the United States, the Kaiser Wilhelm Institute for Chemistry was flying a flag with the swastika, and Lise was left trying to understand what it meant for her scientific community.

Germany’s most famous scientist, Albert Einstein, had very publicly resigned from the Prussian Academy of Science and renounced his German citizenship. “I do not intend to put my foot on German soil again as long as conditions in Germany are as they are,” he said.

Lise regretted the loss. She had first met Einstein in 1909 at a conference in Salzburg, Austria, where she had also given a report. Einstein had rattled the audience with his startling concept that light must behave like both an undulating wave and a stream of particles. But what Lise most remembered all these years later was how easily and logically he had explained his special theory of relativity, deriving from it the equation E = mc² and showing “that to every radiation must be attributed an inert mass.” As a physicist just starting out, she had found this idea “overwhelmingly new and surprising.”

Although the wave-particle theory of light had gone over her head, she had been impressed. Einstein was a few months younger than she and already a star, having published his theory of relativity in 1905 at the age of twenty-six. And he had done it while earning a paycheck as a clerk, plodding away in the Swiss patent office. He, too, had once had trouble finding a paid academic position.

Later, Lise had become acquainted with Einstein on a more personal level in the home of her mentor Dr. Max Planck, and she had often listened to the two physicists play chamber music in the evenings, with Einstein on violin and Dr. Planck on piano.

On April 7, 1933, the news was even worse. The Nazis passed their first race law, barring Jews from all civil service. Suddenly 20 percent of the university scientists in the country were dismissed, including Lise’s nephew, Otto Robert Frisch, in Hamburg. Others resigned in protest, most notably Nobel laureate James Franck at the University of Göttingen. Although his status as war veteran allowed him to remain at his post despite his Jewish heritage, he refused to serve a state that treated its Jewish citizens as alien enemies.

The dismissal sent a slew of scientists out of Germany to countries that welcomed them. The emigrants sought the freedom to continue their work in an environment where their skills and knowledge would be seen as an asset, not a threat. They spread out across Europe, with several settling in England. Others ended up in the United States, eventually working on a secret military operation to end the war Hitler would start in 1939. The very people Hitler seemed to want to shun would be just as eager to bring about his end.

To Lise, the departures of Frisch and Franck and so many others was a real blow. For the moment, though, her position seemed safe. The Kaiser Wilhelm Institute, funded partially by industry, had never been under direct government control, and she was an Austrian citizen. But she felt isolated in an institute where colleagues were showing up for work in the brown shirts of the Nazi Party. She spent many sleepless nights worrying about the future but continued working in the lab and filling in for Hahn as institute director.

Lise regularly kept him updated, and by May she was imploring Hahn to return quickly after his semester at Cornell was over and not travel to California, as he was now planning to do.

That month Dr. Planck, as president of the Kaiser Wilhelm Society, visited Hitler to pay his respects to the new chancellor. Unbeknownst to Lise at the time, Dr. Planck took the opportunity to speak up for his Jewish colleagues. By then a world-famous Nobel laureate, he argued that “forcing worthy Jews to emigrate would be equivalent to mutilating ourselves outright, because we direly need their scientific work and their efforts would otherwise go primarily to the benefit of foreign countries.” Hitler was not interested in rational discussion, however, and went off on one of his notorious rants, working himself into such a fit that the dignified scientist could only sit quietly until he was permitted to withdraw. The Nazis would harass him for years for his sympathies, but Dr. Planck never spoke of the “horror” of that meeting to his colleagues until after the war.

Hahn returned to Berlin in July. By then the Nazis had set upon a course of systematically pushing “non-Aryans” out of German life. Lise’s Austrian citizenship continued to protect her as laws stripped German Jews of their citizenship and all civil rights. Race laws restricted the jobs Jews could hold, the businesses they could own, and even the things they could buy.

But on March 13, 1938, Lise’s protection disappeared overnight. Germany annexed Austria, and suddenly the race laws applied to her.

As much as it pained her, Lise realized that she had to leave her beloved laboratory and give up her life in Berlin. It was only a matter of time before she would lose her job. Niels Bohr invited her to Copenhagen, but when she applied for a visa, the Danish consulate would not accept her Austrian passport. She had to seek new documents from the Nazi government. Of course her request was denied. By then the Nazis were restricting Jews’ travel abroad. As a scientist, she was expressly forbidden to leave.

Lise’s options were limited. Only the Netherlands and Sweden were likely to accept her with an Austrian passport, and a paid position as a physicist was hard to come by since so many scientists had left Germany. Her friends abroad worked tirelessly on her behalf, and Bohr finally found her a position in Stockholm. All she had to do was get out quietly and quickly before the Nazis officially sealed the border against her. She almost decided not to leave, afraid that she’d be arrested, but on July 13, 1938, she boarded a train and, accompanied by a Dutch friend, crossed into the Netherlands without incident. Lise was safe.

In a laboratory in Rome that July, Enrico Fermi was concerned. He was the most prominent physicist in Italy, with his laboratory full of the best minds in the country. He had brought fame and honor to his beloved country with his research on radiation and the effects of slow neutrons. But for the past two years, Italy’s fascist government had been Germany’s ally, and now it had finally embraced Hitler’s racist ideology. Fermi’s wife, Laura, was Jewish. If similar race laws were passed, Laura would fall prey to them, and so would their children. It did not matter how famous he was or what he could provide to their country: Italy would have no mercy. He would have to leave as well. He had to come up with a plan.

Lise Meitner had not been happy about the idea of leaving Berlin. At that time, she was not sure she wanted to go to Stockholm. She would have preferred England, where she had friends and the development of atomic physics was already under way. However, thanks to a friend, the offer to work at Manne Siegbahn’s new Nobel Institute for Experimental Physics was her only secure option. From the Netherlands, she flew to Copenhagen, where she was met by the friendly and familiar face of her nephew, Otto Robert Frisch. She spent a few days there with Niels Bohr and his wife before heading on to Sweden.

Naively, she had believed things would work out as they had in Berlin. Unfortunately, unlike Hahn, Siegbahn was not happy to have a woman in his institute, and the spirit of collegiality that had permeated the Kaiser Wilhelm Institute in Berlin was nowhere to be found in Sweden.

The new laboratory held no appeal for her. It was sterile, plain and white, and it still lacked all the necessary equipment for conducting experiments. But what she missed most were her companions; she longed for the friendships she had built during the years alongside Hahn and Strassmann and hovered over the experiments that had yielded so much to her.

Then one day she had a visitor—two, actually. A small, slightly balding man, accompanied by an attractive woman, entered her laboratory, shouting her name. Confusion turned to shock when she realized who had come to visit. Fermi and his wife, Laura, were in the country to pick up the Nobel Prize he had been awarded for his work with neutrons. Lise was flattered by the visit. As he introduced the two women to each other, Enrico noticed that Lise looked tired and worried and wore the tense expression that all refugees had in common. Laura also sympathized with Lise’s dilemma of being in a country that was not her own.

The Nobel Prize had given Fermi’s family the excuse they had been looking for, not only with a financial reward but also the ability to travel. They had been able to go abroad as a family, and now that they were out of Italy, they were not going back. In about ten days, they would be sailing to the friendlier shores of the United States. He hoped one day to meet Lise again under better circumstances.

Unlike the work Lise was now performing in Stockholm on her own, much of the work she had done at the Kaiser Wilhelm Institute in Berlin had been a joint effort between three scientists: herself, Hahn, and Strassmann.

One winter morning when her nephew Otto Robert Frisch joined her for breakfast, she handed him Hahn’s latest letter. On December 19, 1938, Hahn wrote, he and Strassmann had bombarded uranium with a radium-beryllium neutron gun. The result was a small sample that performed like barium, something that could not possibly be. Could Lise make any sense of that? Uranium, atomic number 92, could not suddenly change into barium, atomic number 56, could it? It was a loss of thirty-six units on the element scale. Frisch thought it must be a mistake, but Lise assured him that Hahn was too good a chemist for that.

It was a curious letter, providing a puzzle for Lise to solve. And she had always loved a good puzzle. The idea was almost unimaginable. When neutron experimentation had started, everyone found results that did not fit the expected pattern. Fermi in Rome could not come up with a solution that he deemed convincing. Irène Joliot-Curie and Pavle Savić, and even Hahn and she herself had all thought that the nuclei had captured the neutrons and created new elements heavier than uranium. But now, after a second and third look, Hahn and Strassmann had found something lighter. Maybe, Lise thought, it was not that the neutrons were behaving inappropriately; it was that the scientists who were thinking about the issue were doing so with a closed mind. Perhaps a new rule had to be developed, one adapted to this problem that, if one really thought about it, was not really a problem at all but simply a new surprise, something to force scientists to think more critically about an issue.

She could not recall anyone saying that an atom could not be split in two. Going back to the seminar she had attended with Einstein, she remembered his words precisely: “There is not the slightest indication that energy [in the nucleus] will ever be obtainable,” he had told his audience. “It would mean that the atom would have to be shattered.” But really, what had he said? Lise wondered. It all depended on how one interpreted his statement. It didn’t mean that it could not be done. What Einstein had suggested was that to do so, to get to the nucleus, one really had to split it in two portions. And so far, no one had done it.

Lise and Frisch went off for a walk as they tried to sort out the puzzle. Clearly, the lighter barium had to be a fragment of the uranium nucleus, but how had it happened? Neutrons never broke anything other than a proton or alpha particle away from the nucleus, or so they thought. And a nucleus wasn’t a brittle solid that could be chipped or cracked or broken. They remembered the physicist George Gamow’s theory that a nucleus was more like a liquid drop. What if they could split into smaller drops, gradually stretching, constricting, and finally turning into two drops? It would look something like a dumbbell. The physicists knew that the surface tension of ordinary drops resisted such division, but nuclei were no ordinary drops. They were electrically charged, and that diminished the effects of surface tension.

Lise calculated that the electrical charge of uranium was indeed strong enough to overcome the surface tension, so the nucleus could possibly be unstable enough to divide when a neutron struck it. But the electrical charge of the two new drops would repel, driving them apart at a high speed. Where would that energy come from? Lise remembered Einstein’s equation from that conference so many years ago, E = mc². She worked out the masses of the new nuclei, and Frisch calculated the energy needed for the repulsion. It all fit.

It was the breakthrough that explained everything, and it had come on a snowy day in Sweden.

Frisch returned to Copenhagen and promptly told his boss, Niels Bohr, of their speculation. Bohr agreed with their theory immediately and urged them to publish a paper. Lise and Frisch decided to write a one-page note about their theory, backed up by physical evidence of the nuclear fragments. They consulted repeatedly over the telephone, the line between Copenhagen and Stockholm as crackly as the ice outside.

Frisch designed a physics experiment to detect the fragments by measuring the bursts of ions they produced. It worked perfectly. Proof in hand, he wrapped up the final paper. Now ready to let the world know of this nuclear fission, he sent their note to the British journal Nature.

Frisch’s note to the journal read in part: “It seems therefore possible that the uranium nucleus has only a small stability of form, and may, after neutron capture, divide itself into two nuclei of roughly equal size (the precise ratio of sizes depending on finer structural features and perhaps partly on chance). These two nuclei will repel each other and should gain a total kinetic energy of c. 200 MeV, (mega-electron volt) as calculated from nuclear radius and charge. This amount of energy may actually be expected to be available from the difference in packing fraction between uranium and the elements in the middle of the periodic system. The whole ‘fission’ process can thus be described in an essentially classical way.”

It was a startling note, one that would have profound repercussions across the world. In time, some would point to this moment in history as the start of the atomic age, and to Lise Meitner as the originator of the atomic bomb.