14.11: Process of Science- Lise Meitner and Otto Hahn

There are a few rightfully famous scientists from this chapter who could be highlighted: Albert Einstein and Marie Curie. These two are usually listed at the very top of any list of scientists of the 20^th century, and among the top five to ten of any list of scientists of all time. Because of their relative recency, they are more understandable to us than someone like Galileo or Newton who lived in times much different than our own. Not only were their scientific accomplishments extremely significant, but their personal stories were quite compelling. Marie Curie was the first women to win a Nobel Prize, and one of only a few scientists to win more than one. Einstein was a Jewish refugee who won a Nobel Prize (but not for his most famous and groundbreaking work), and was also a scientific celebrity in many regards. Both of them have been fixtures of popular culture for decades, inspiring many books and even movies.

Instead of highlighting these two, we will instead look at the work of Lise Meitner and Otto Hahn. Both the work and life of Lise, in particular, were a fusion of those of Einstein and Curie. Not only was her work building on the work of both Einstein and Curie, but her life was an intersection of their identities. Though Einstein and Curie became famous in part for their identities, Meitner’s existence was almost erased (both scientifically and literally) because of the intersection of those identities.

Meitner was the second woman to receive a doctorate in physics from the University of Vienna, and then tried to find ways of staying connected to scientific work at a high level. She was able to receive a position as an assistant to Otto Hahn at the Friedrich Wilhelm University. This position was unpaid for several years, and many at this University did not believe women should be there at all! In fact, Meitner was only allowed to enter into the lab space where she worked through an external door, and was not even provided a restroom to use while she was there. But she loved doing scientific research so much that she was willing to accept these conditions and was fortunate to have family who could support her financially in this endeavor.

Otto Hahn and Lise Meitner were about the same age, and she found him less intimidating than some of the other potential work colleagues at the University. Some have attributed Hahn’s willingness to accept a woman co-worker as an equal to his time spent in Montreal where gender roles were not as rigid as they were in Germany at the time. Hahn was a chemist, and was attempting to do the sort of work that Marie Curie had done about a decade before: discover new element based on their radioactive properties. As a physicist, Meitner was more interested in the radiation itself than the new elements. As has happened many times throughout the history of science, this combination of diverse perspectives led to a great scientific breakthrough. Particularly the combination of Hahn’s experimental work and Meitner’s theoretical work. But Meitner would face additional personal challenges before this breakthrough occurred.

Figure \(\PageIndex{1}\): A photograph of Otto and Lise from early in their career. The exact data and credit for the photographer are unknown. Public Domain. Wiki Commons.

Hahn and Meitner had a thirty year working relationship. They were considered for Nobel Prizes in both chemistry and physics for their work on radioactive elements at many points during this time. They had a break from this work during World War I, when Hahn was involved in making chemical weapons and Meitner was involved as an X-Ray nurse-technician for Austria. Meanwhile, Marie Curie was creating X-Ray equipment on the other side of the fox holes in France. Meitner returned to the lab before Hahn did, and she followed Hahn’s instruction via correspondence to continue the chemical analysis that had been underway. It was not the last war that would separate them, nor the last time they would need to work via correspondence.

Many prominent Jewish scientists, such as Albert Einstein, were able to flee Germany in the mid 1930s as the Nazis came to power. But as a woman of Jewish ancestry, Lise Meitner was in a much more precarious position. She had enjoyed working with Hahn for all these years and thought that a life without being able to do science was not worth living. She did not know where else she could go to do the sort of fulfilling work that she had partnered with Otto Hahn for the past three decades. When her home country of Austria was invaded in 1938, she realized that she had to leave, but it was much more dangerous now than it had been earlier. Neils Bohr and other Danish physicists attempted to find a position for her somewhere in Northern Europe, but the political situations were changing on almost a monthly basis and she didn’t have the right papers now that Austria had been taken over by the Nazis. Eventually they came up with a plan to smuggle her out, but kept it secret from all of her colleagues, including Hahn, until the day before she was to leave. When Hahn found out, he gave her a diamond ring that had been his mothers "in case she needed it." She kept the ring until the day she died, despite what would happen later. She rode the train from Germany to the Netherlands with Danish physicist Dirk Coster. When the German border guards boarded the train and asked for papers, Coster presented his papers and Lise sat quietly beside him until they left. Fortunately, she was not asked. It was perhaps the only time in her life that being overlooked was beneficial to her. Meanwhile Hahn initially told his colleagues at Friedrich Wilhelm University that she was on vacation, and then, after the summer break, that she had retired.

Lise eventually ended up in Stockholm, but was quite miserable. There was nobody to collaborate with in the type of work she had been doing. When her belongings were shipped to her several months later they had been destroyed. And eventually she got word that her family members were being sent away to concentration camps.

Lise and Otto continued their collaboration via correspondence throughout the rest of that year. It was quite productive for Hahn, and the only avenue for continued meaningful work for Meitner. Otto was attempting to make elements larger than uranium by bombarding it with slow moving neutrons, but was instead detecting elements smaller than uranium. In a letter to Meitner, Hahn said “Perhaps you can come up with some fantastic explanation. We ourselves realize that it can't actually burst apart into barium.” Meitner’s initial response was skeptical as well, but also reminded Hahn that “in nuclear physics we have experienced so many surprises, that one cannot unconditionally say: 'It is impossible.'" Hahn had felt urgent about publishing the results and sent the article for publication before the Christmas break and just days after his letter to Meitner. He would revise it twice over the course of the next month. The results were quite puzzling. How could barium be created from uranium? And yet that is exactly what the experimental results were telling him again and again.

Meanwhile, Lise and her nephew Otto Robert Frisch were spending the holidays in Sweden and discussing Hahn’s latest letter. Frisch was also a nuclear physicist, and was among the many Jewish scientists who left Germany when Hitler came to power in 1933. It was a smaller than usual gathering for the Meitner family, as many of their family members were displaced or imprisoned at this point. Otto was skiing and Lise walking through the snow as they discussed what to make of the bizarre results. The existence of barium suggested that the nucleus must have split in two if the experimental results were to be trusted, which Meitner assured her cousin that they should be. As physicists, they had to consider what might cause this. They calculated that the electrical repulsions within the nucleus of uranium 235 were very close to the strong force holding it together. As such, a very small disturbance would likely be sufficient to break such a nucleus apart. But they also needed to determine what energy source would power the rapid acceleration of the two new nuclei away from each other. Meitner realized that Einstein’s equation E=mc² might explain the results. When they did the calculations they found that the amount of energy necessary for the process could be explained by the difference in mass between the products and the reactant. Frisch was able to conduct an experiment in his lab to confirm this, and the two of them published their results at the beginning of 1939.

Neils Bohr and the physics community at large immediately saw the veracity of these results and there was much interest in them. The correspondence between Meitner and Hahn became strained as word got out about the discovery of nuclear fission. Bohr was presenting Meitner’s findings at a prominent meeting in Washington D.C. by the end of January. Bohr made very clear in this presentation that it was Meitner and Frisch who had correctly interpreted the experiments of Hahn and Strassmann, he feared that if he did not speak she would not get the credit she deserved. But Hahn was not acknowledging this in any of his public comments or publications. When Meitner expressed frustration with this to Hahn, his response was “I don’t give these things much weight, of course, but I didn’t want to confess to [a work colleague] that you were the only one who found out everything immediately.” Hahn feared that it might jeopardize his position at the University if it came out that he was collaborating with a Jew, and asked Meitner for loyalty in his correspondence. He thought the little bit he had done to aid in her escape was sufficient. Meanwhile, the Nazis had taken away Meitner’s access to her pension and removed her name from the articles she had already published with Hahn. Hahn acknowledging her current contributions was the only way for her voice to be heard correctly within the scientific community, so it was troubling for her that he refused to do so. Meitner’s time was also divided throughout 1939, as she was working to get the rest of her family to safety. Their correspondence throughout the early months of 1939 grew increasingly fraught.

By September, barely a year beyond when Hahn had given Lise the diamond ring the day before she escaped Germany, the Nazis were invading Poland and everything that had been strained between them was ratcheted up to a new level. Albert Einstein had written a letter to President Roosevelt, warning him that the Nazis were probably working on an atomic bomb. There were many obstacles to be overcome in the process of developing a nuclear bomb, but the Manhattan Project was able to convince Frisch, Bohr, and almost every other nuclear physicist of note (particularly those who had fled Germany already) to participate. The two notable exceptions were Einstein and Meitner. Einstein was not given clearance to participate in the project because of his political views, while Meitner simply said she wanted to have nothing to do with a bomb.

The Allied forces were highly concerned that the Nazis might be working on an atomic bomb themselves. In February 1944, they bombed the University where Hahn worked as an effort to disrupt this assumed work. A special allied mission arrested Hahn and several physicists including Werner Heisenberg in April 1945, transporting them across Europe several times, and eventually confining them in comfortable house arrest at Farm Hall, where their conversations were recorded for several months. When Hahn and the others heard about the bombing of Hiroshima in August, they initially expressed shock at how much farther along the Allied forces were in their development of the atomic bomb. And then they decided that it was better that they had not been successful in creating an atomic bomb, and even that they were morally superior to the Allied scientists for having made the choice to focus on nuclear energy as a source of power instead of as a weapon. They wrote a memorandum explaining their logic, and they doubled down on the narrative of Hahn and Strassmann as the discoverers of nuclear fission as part of this writing.

Throughout this time, Lise was largely in the dark about what was going on. Although she had some correspondence with Bohr and Frisch in the U.S., they were not allowed to even mention that they were working on a bomb. Lise found out about it after the bombs were dropped in Japan when a reporter came to her to ask about it. She was horrified to learn that anything she had done would be put to such use, but still she was reported to have been involved in the process by much of the media at that time, often being called the Mother of the Atomic bomb.

While he was still a prisoner of war, Hahn was awarded the Nobel Prize in Chemistry a few short months after the war had ended for his discovery of nuclear fission. His location was still top secret at this time, so he had to read about it in the newspaper. He was repatriated into British controlled Germany in early 1945, but it was difficult to get permission to travel until much later in the year. He was finally able to give his acceptance speech in December 1946, over a year after he had learned about winning the award. Lise attended the ceremony, hoping that he would mention her contributions at some point during his speech, but he did not. She was quite disappointed by this, and by Hahn’s lack of “thoughtfulness and a certain strength of character,” as she wrote to a colleague afterwards. Many of her colleagues joked that the crowning achievement of her career was winning a Nobel Prize for Otto Hahn. This erasure of Lise Meitner’s work continues to this day with her absence in the recent popular film Oppenheimer.

They both tried to make amends in their own ways in the years that followed. Meitner became an advocate for nuclear peace, and when Hahn gave her some of the money from the Nobel Prize she donated it to this cause. Despite their differences, Meitner still had a fondness for Hahn and simply wished he had done more to acknowledge his complicity with all the horrors done in Nazi Germany even if he was not a Nazi himself. They both died in 1968 at the age of 89. Lise Meitner’s gravestone reads “A physicist who never lost her humanity.”

There were several transuranium elements discovered during the secrecy of the Cold War, and which remained officially unnamed because there were disputes about who had discovered them. This dispute was finally resolved in 1997, five years after the Farm Hall transcripts were released to the public. Although the United States team proposed an element named after Otto Hahn, the disputed element was eventually named Dubnium after the location in Russia where it had been isolated. The German team was awarded the rights to name three elements, and chose to name one of them after Lise Meitner. Lise Meitner and Marie Curie are the only non-mythological women with elements of the periodic table named after them (and technically Curium is named after both Marie and her husband Pierre). There are eight elements named after mythological women.

Figure \(\PageIndex{2}\): A photograph of Meitner on the steps of a college talking to students in 1959. Public Domain. Wiki Commons.

Additional Resources:

an article by Meitner about her life.

a biography of Meitner written in the 1990s.

An article about Otto Hahn's role in Nazi Germany.

An article about the transcripts from Farm Hall.

A short biography of Meitner (and others).

A fairly recent podcast about Meitner's experience. (this links to the first of two parts)

A recent biography written by the person interviewed in this podcast.