Lise Meitner

Austrian physicist

• Born: November 7, 1878; Vienna, Austria-Hungary
• Died: October 27, 1968; Cambridge, England

Physicist Lise Meitner’s joint research with chemist Otto Hahn, and later Fritz Strassmann, yielded the discovery of new radioactive elements and their properties and paved the way for the discovery of uranium fission.

Primary field: Physics

Specialties: Nuclear physics; atomic and molecular physics

Early Life

Lise Meitner was the third of eight children born to Hedwig Skovran and Philipp Meitner. She was interested in mathematics and physics from a young age. After receiving a matriculation certificate from the gymnasium (secondary school) in Vienna, she went on to the University of Vienna, where, from 1901 to 1905, she studied mathematics, physics, and philosophy. In 1902, she began her study of theoretical physics under the tutelage of Ludwig Boltzmann, who was an advocate of atomic theory—the idea that all matter is composed of tiny, invisible, and (at the time) indivisible components. This was by no means generally accepted by physicists of the day, but in Boltzmann’s view, the discovery of radioactivity supplied the experimental proof that tiny particles, or atoms, form the building blocks of all things.

In 1905, Meitner finished her doctoral thesis on heat conduction in nonhomogeneous bodies, becoming only the second woman to receive a doctorate in science from the University of Vienna. She soon became familiar with the new field of radioactivity and was ready to enter the realm of atomic physics at the beginning of a promising new period in that branch of science.

Life’s Work

After graduation, Meitner went to Berlin to attend the lectures of theoretical physicist Max Planck, and what was intended to be a short stay became a thirty-one-year period of research on the frontiers of atomic physics and radioactivity. Planck was one of the world’s most notable scientists, having formulated the theory of thermal radiation in 1900—a major advance in the developing field of quantum mechanics—and having been one of the first to recognize and stress the importance of Albert Einstein’s special theory of relativity.

As important as Meitner’s association with Planck was, however, it was her friendship and collaboration with Otto Hahn that would change the course of atomic science. Meitner and Hahn met in 1907, the same year Meitner came to Berlin, and she decided she wanted to work with Hahn and keep to the study of radioactivity. After some persuasion, the two received permission from Emil Fischer, the director of the Chemical Institute of Berlin, where Hahn was working, to become a research team, with the provision that Meitner promise not to go into the chemistry department, where the male students did their research. For the first few years, Meitner and Hahn’s research was confined to a small room originally planned as a carpenter’s shop. When women’s education was officially sanctioned and regulated in Germany in 1909, Fischer gave Meitner permission to finally enter the chemistry department.

In 1912, the Kaiser Wilhelm Institute for Chemistry was opened as a part of the University of Berlin. Hahn became a member, and Meitner became an assistant to Planck at the university’s Institute for Theoretical Physics, allowing the Meitner-Hahn partnership to continue with greater facilities and an enlarged staff. Hahn, a future Nobel laureate, brought to the team his knowledge of organic chemistry; Meitner brought her expertise in theoretical physics and mathematics. Together they would be responsible for some important advances, including their 1917 discovery of the rare radioactive element protactinium (atomic number 91).

From 1917 to 1926, Meitner continued to conduct her own research on the nature of beta rays. The interpretation of the physical properties of radioactive substances continued to be an area of personal interest, and she was the first to maintain that in the process of disintegration of radioactive materials, the emission of radiation follows rather than precedes the emission of the particles. During this time, she won considerable acclaim, and in 1926 she was named professor extraordinary at the University of Berlin. Adolf Hitler’s anti-Semitic decrees would ultimately force her to leave this post; although Meitner had been raised Protestant, both of her parents were of Jewish background. For a few years after Hitler came to power in 1933, however, the change in government did not affect Meitner’s collaboration with Hahn.

In the early 1930s, nuclear physics made profound and dramatic advances, with James Chadwick discovering the neutron and Frédéric and Irène Joliot-Curie discovering artificial radioactivity. In 1934, Meitner and Hahn began to follow up the work of a group of scientists in Italy, headed by Enrico Fermi, who had bombarded uranium with neutrons and found several radioactive products thought to be transuranic elements (elements with atomic numbers higher than that of uranium, 92). Meitner and Hahn soon found a new group of radioactive substances that could not be identified as any of the elements just below uranium in the periodic table. Only one assumption seemed possible: that they were higher. Still, unanswered questions and puzzling results remained, even though another scientist, Fritz Strassmann, had joined Meitner and Hahn.

As the spring of 1938 arrived and Austria was occupied by the Nazis, Meitner was forced to leave Germany. She went first to the Netherlands; then to Copenhagen, Denmark, as a guest of Niels Bohr and his wife; and finally to Stockholm, Sweden, to work in the new Nobel Institute, where a cyclotron was being constructed.

In Berlin, Hahn and Strassmann had continued their work after Meitner left. She wrote to Hahn for data on the properties of the substances produced by their experiments. Hahn and Strassmann conducted more tests to prove the existence of radium but could only identify products resembling barium isotopes. Meitner discussed this new information with her nephew, the physicist Otto Frisch. Meitner and Frisch concluded that the uranium nuclei had split into two fragments and that a large amount of energy had been released. Immediately, they prepared a communication for the British science journal Nature in which they introduced the term nuclear fission to elucidate scientific principles previously thought to be impossible. For a short time after 1939, Meitner continued to investigate the nature of fission. In 1950, independently of others doing similar research, she advanced ideas concerning the asymmetry of fission fragments and worked on various aspects of the shell model of the nucleus.

In 1947, after spending half a year as a visiting professor in the United States, Meitner became a citizen of Sweden, retired from the Nobel Institute, and went to work in a small laboratory that the Swedish Atomic Energy Commission had established for her at the Royal Institute of Technology. In 1960, she left Sweden and retired to Cambridge, England. She died in 1968, a few days prior to her ninetieth birthday.

Impact

Meitner helped revolutionize the science of physics and its concepts. Her active participation in nuclear research resulted in the discovery of new elements and paved the way for the discovery of atomic fission, a term she helped coin and a process she helped interpret correctly. She entered her field at a time when women in science were not just a rarity but an oddity, and she overcame the prejudices and preconceptions she faced to make some revolutionary contributions to nuclear physics.

Honors came to Meitner from all quarters throughout her long life. She earned a distinguished reputation in the 1920s, receiving the 1924 Leibniz Medal of the Berlin Academy of Sciences and the 1925 Lieben Prize of the Austrian Academy of Sciences. In 1947, she was awarded the Prize of the City of Vienna, and in 1949, she won the Max Planck Medal. She was elected a foreign member of the Royal Society of London in 1955 and of the American Academy of Arts and Sciences in 1960. In 1966, she shared the United States Atomic Energy Commission’s Enrico Fermi Award with Hahn and Strassmann. In addition, four American educational institutions (Syracuse University, Rutgers University, Smith College, and Adelphi College) awarded her honorary doctorates in science.

Bibliography

Graetzer, Hans G., and David L. Anderson. The Discovery of Nuclear Fission: A Documentary History. New York: Reinhold, 1970. Print. Reprints the original papers and reports by scientists who first uncovered the problem and meaning of nuclear fission.

Meitner, Lise. “Looking Back.” Bulletin of the Atomic Scientists 20.9 (1964): 2–7. Print. An autobiographical account of Meitner’s life, covering her youth through the discovery of atomic fission.

Rife, Patricia. Lise Meitner and the Dawn of the Nuclear Age. Boston: Birkhäuser, 1999. Print. A biography interpreting Meitner’s life and describing her work leading to the discovery of fission.

Sime, Ruth Lewin. Lise Meitner: A Life in Physics. Berkeley: U of California P, 1996. Print. Provides a comprehensive chronicle of Meitner’s life, career, and contributions to atomic and nuclear physics.

Sparberg, Esther B. “A Study of the Discovery of Fission.” American Journal of Physics 32.1 (1964): 2–8. Print. Reviews the history of the discovery of fission and discusses Meitner’s place in that history.