Meitner was born in Vienna on November 7, 1878, the third of eight children. She attended the University of Vienna, where she received a doctorate in physics in 1906. She was attracted to the University of Berlin by the work of Max Planck. At Berlin, she encountered blatant sexism that was not unusual in science at the time. It is reported that she was allowed to work with the great chemist, Emil Fischer, only with the understanding that she never enter a laboratory where men were working. At Berlin, she also met Otto Hahn, with whom she collaborated for thirty years.
Meitner devoted her life to the study of nuclear phenomena. In one of their first joint publications, for example, Meitner and Hahn described the recoil of atoms as a result of alpha particle emission. Their analysis provided a method for producing very pure samples of radioactive materials that eventually became a standard procedure. She devoted considerable time to the analysis of electron changes that take place in the atoms of both stable and radioactive isotopes. With Hahn, she discovered protactinium (element 91) in 1918 and the phenomenon of nuclear isomers, atoms that have identical nuclear structures, but that decay by different mechanisms (1921).
Meitner's most famous accomplishments, however, will always be associated with the process of nuclear fission. In 1932, the English physicist James Chadwick had discovered the neutron. Immediately, those scientists interested in nuclear reactions realized the practical significance of Chadwick's discovery for their own field of research. Since it carries no electrical charge, the neutron is not repelled by the atomic nucleus. That property would appear to make the neutron a highly desirable "bullet" in nuclear reactions.
As a result, nuclear scientists throughout the world began to bombard all kinds of elements with neutrons. The Italian physicist, Enrico Fermi, was particularly active in this kind of research. In a single year, he bombarded sixty-three different elements with neutrons.
One of Fermi's experiments was of special interest, the bombardment of uranium with neutrons. Fermi had expected that this reaction might result in the formation of a new element, one with atomic number 93. Since no such element exists naturally, that experiment would have resulted in the formation of the first synthetic element.
In fact, the analysis of Fermi's experiment seemed to confirm the existence of such a transuranium element. But the results were so confusing that Fermi himself did not recognize this fact. Meitner and Hahn decided to repeat Fermi's experiment in order to unravel the ambiguous results he had reported.
Between 1935 and 1938, they studied in great detail the products formed when neutrons collide with uranium nuclei. Then, in 1938, Meitner decided to flee Germany. As a Jew, she was threatened by the rise of Hitler and the Nazi party. She made her way first to the Netherlands and eventually to Sweden. Fritz Strassman took her place with Hahn in the neutron-uranium research.
Hahn and Strassman soon recognized that a remarkable event was taking place in the neutron-uranium experiments. Apparently the collision of a neutron with the uranium nucleus resulted in the break-up of the nucleus into two large, roughly equal pieces. This result was so at variance with traditional theory, however, that Hahn and Strassman hesitated to publish their results.
Meitner was not so hesitant. Having been kept informed by Hahn of his experimental results, Meitner had worked out an explanation for these results. With her nephew, Otto Frisch, she proposed that, when struck by a neutron, the uranium nucleus "fissioned," a term they proposed.
Meitner and Frisch published this theory in January 1939, only a month before Hahn and Strassman published a similar theory. Meitner and Frisch further predicted that, in addition to the barium (atomic number 56) that had already been identified, an isotope of krypton (atomic number 36) would also be found among the products of uranium fission. Very shortly thereafter, Hahn and Strassman confirmed the existence of a krypton isotope among the products of fission.
In recognition of her contribution to the understanding of nuclear fission, Meitner was awarded the 1966 Fermi Award, along with Hahn and Strassman. After reaching Sweden in 1938, she continued her research, first at the Nobel Institute for Physics, and later at the Atomic Energy Institute. She moved to Cambridge, England, in 1960 and remained there until her death on October 27, 1968.
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