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The Discovery of Nuclear Fission
The dramatic splitting of the atom - nuclear fission - was a discovery that changed our world. Yet few know that it was a woman physicist, the Austrian Lise Meitner, who discovered the power of nuclear energy soon after her dramatic escape from Nazi Germany. Ironically, Meitner’s research partner of thirty years, Otto Hahn, was the sole recipient of the 1944 Nobel Prize for Chemistry for the discovery of fission - a “discovery” that Meitner had already interpreted in 1938, shortly after her forced emigration from Nazi Germany.
Meitner’s exclusion from sharing the Nobel Prize was thus integrally related to her 1938 escape from Nazi Germany, and to the consequent social “marginalization” of her physics research and theoretical insights. Such racial and gender prejudice were, and still are, dramatic backdrops to our modern era. Eleanor Roosevelt aptly stated in an 1945 NBC Radio interview that “we are proud of your contributions as a woman in science” and that helped Meitner heal part of her deep pain in the rejection and escape from Nazi Germany.
The Kaiser Wilhelm Institute of Physics, which she and Otto Hahn had administered since World War I, was the backdrop for 35 years of her pioneering research in radio-physics and radioactive processes. Yet many were shocked that at the end of World War II, it was Otto Hahn who was alone awarded the Nobel Prize (in Chemistry) for his “discovery” of nuclear fission, when it was Lise Meitner who in 1938 interpreted the process of uranium splitting in two - and releasing a tremendous amount of energy in the process.
How these circumstances came about and how they fit into the evolution of Meitner’s social conscience and her abhorrence of war are some of the subjects discussed in the book by Patricia Rife (Lise Meitner and the Dawn of the Nuclear Age) (Boston: Birkhauser 1999). The following article is an abridged account of Lise Meitner’s life and scientific journey based on the book, which can be ordered at www.Birkhauser.com
Meitner’s early years in Vienna
As a child, Lise Meitner showed an early propensity for mathematics. She was privately tutored, since her father insisted that each of his daughters receive the same education as his sons (three of Lise’s sisters also earned their Ph.D.s). Her parents were assimilated Viennese Jews who did not practice Judaism. Her father Philipp was a lawyer whose family came from Moravia (the family name came from the Moravian village “Meitheim”). In 1873, he married Hedwig Skovran whose family had emigrated from Russia to Slovakia. They had eight children of whom Lise Meitner was the third. As a young woman, Meitner focused her talents on passing the difficult entrance examination to the University of Vienna, a challenge since girls in Austria were not permitted to attend the normal boys’ high school.
At age 23, she was the first woman admitted to the university’s physics lectures and laboratories. From 1901 to 1906 she studied with experimentalist Anton Lampa, Stefan Meyer, and later, the famous theoretician Ludwig Boltzmann, who vigorously championed the reality and existence of unseen atoms. Lise Meitner was the second woman to receive a Ph.D. in Physics from the University of Vienna.
There she was introduced to Max Planck, father of quantum theory, who traveled to Vienna after the tragic suicide of Boltzmann. Planck became Meitner’s mentor and an important friend, and in 1907 invited her (at age 29) to Berlin for postdoctoral study and research - a move that was to change Meitner’s career and life path.
Research in Berlin
For several years, Meitner was not permitted access to the laboratories of the Heisenberg, Niels Bohr and von Laue; Meitner was again nominated for the Nobel Prize in Physics three times by Niels Bohr after WWII.
Throughout the 1930s, Meitner and Hahn had been competing with the Paris team of Irene Joliot-Curie and Rome’s Enrico Fermi to unravel the complexities of the mysterious “transuranic” elements. But while fiercely focused on this scientific competition, Meitner also remained an aware citizen, recording the behavior of the power-gaining Nazis. For example, when Einstein, who was safely out of Hitler’s range in America on a lecture tour in 1933, spoke out against Hitler, the Nazis retaliated by having his life savings confiscated, his books burned, and other atrocities committed against his work on relativity.
Meitner recorded many of these atrocities in detailed letters to her colleagues throughout the 1930s. Fleeing Berlin in 1938 after the Anschluss Meitner’s highly focused uranium research at the Kaiser Wilhelm Institute for Chemistry came to an abrupt end in 1938, when the Third Reich invaded Austria and thereby brought Austrians under the Third Reich’s racial laws. The dangers increased even more when the National Socialists issued an order forbidding “famous scientists” to “travel abroad.” Unknown to Lise Meitner, her escape route from Berlin was orchestrated by the international physics community and Danish physicist Niels Bohr. Dirk Coster, a Dutch physicist, secretly accompanied Meitner through the stressful train journey across Nazi borders into the Netherlands. With the assistance of Bohr, she departed for Copenhagen and then Stockholm.
Lonely, she lived on a meager research assistant’s salary, working at the new Nobel Research Institute of Physics for the rest of the war years. Her correspondence with Hahn during December 1938 demonstrates that, even from abroad, she continued to urge Hahn and their assistant Fritz Strassman in Berlin to continue research she had instigated on uranium before she had to flee. In Stockholm, however, many of the Swedish scientists, including Nobel Prize committee member Manne Siegbahn, ignored her while they focused on top secret defense work.
On December 24, Meitner received a troubled letter from Hahn recounting a strange “bursting” he described as occurring to uranium, which formed barium. Hahn begged his trusted colleague to interpret this process: “What would physics say about such bursting?” He had written up their findings and submitted them to Die Naturwissenschaften on December 21 - without crediting her contributions - an act that would eclipse Lise Meitner’s contributions to the discovery of nuclear fission in 1938. Because it was the holiday season, Meitner was with her 29-year-old nephew Otto Robert Frisch, a physicist himself, who had also fled from the Nazis and was at that time at Niels Bohr’s laboratory in Copenhagen.
While taking a hike in the snowy Swedish woods, they animatedly discussed the puzzling “bursting” process Hahn described in his letter. Then they realized that if E=mc2, the mass could not be lost but the nucleus would be “split in two.” (Frisch later dubbed this process “fission,” a term used by biologists to describe the elongated splitting of a cell).
Meitner did the calculations: Such “bursting” would yield tremendous energy! The insight was so dramatic that Meitner excitedly scribbled out the formulas on a scrap of paper there in the woods, urging Frisch to return to Copenhagen’s laboratories and replicate the experiments. She herself returned to Sweden and there, in January-March 1939, wrote a series of articles to be published in Nature with O.R. Frisch on the nuclear fission of uranium. Upon his return to Copenhagen, Frisch immediately informed Niels Bohr about the breaking news of fission. Bohr was traveling, crossing the Atlantic to America, when he received the news.
Later, he and young John Archibald Wheeler at Princeton authored the definitive theoretical paper “The Mechanism of Fission,” based on Meitner’s insight and published research. Through Bohr, by early 1939 the news of fission had spread across America where Fermi, Ernest O. Lawrence and others confirmed fission before Meitner and Frisch’s paper was circulated by Nature. By the fall of 1939, thanks to Einstein’s warning to Roosevelt, fission research became Top Secret in America. Yet it was also Bohr’s tireless efforts that assured Meitner prominence in the international physics community, although Hahn later took “credit” for the “discovery.”
After 1945: getting the recognition she deserved - and even more...
Set against the backdrop of war, intrigue, and prejudices against women in gaining acceptance/admission to a scientific career - Meitner, like her French colleague Marie Curie, was often the only woman in many famous physics circles throughout the early twentieth century - Meitner’s story becomes all the more ironic: In 1945, when she was - finally - recognized in America for her scientific accomplishments and invited to Washington, DC, as “Woman of the Year” by the US Women’s Press Club, Meitner dined with President Harry Truman, who at the dinner honoring Meitner’s accomplishments remarked, “So you’re the little lady who got us into all of this!” Quite the contrary is true, however.
Lise Meitner and Albert Einstein were among the few scientists who did not work on weapons research during World War II. In Sweden she encountered concentration camp victims released due to Count Bernadotte’s efforts, and it was this grim reality that convinced her never to return to Germany or her former life there. When Hahn and Strassmann invited her to rejoin them at the rebuilt Institute for Chemistry in Mainz, West Germany, in 1947, Meitner declined their invitation to form a new Max Planck Institute for Chemistry named after their mentor. Instead, she retired in Sweden on a small pension negotiated through the president, Tage Erlander.
Despite all the difficulties life had placed in Meitner’s path, she spent most of her 60s, 70s, and even 80s traveling, tirelessly continuing to encourage women students to “remember that science can bring both joy and satisfaction to your life.” Lise Meitner’s final years were spent in Cambridge, England, where she had moved to live close to her nephew Otto Robert Frisch. She died there in 1968, at the age of 89.
*** Unedited reprint of the article first published in Bridges [Office of Science and Technology Austria, www.ostaustria.org].
The author, Patricia Rife, holds a Ph.D. in history of science from Union University, Cincinnati, Ohio. She is an e-marketing professor for the University of Maryland University College’s Graduate School of Management & Technology.