- Person
- Lise Meitner
- Lived
- 1878–1968
- Field
- Physics
- From
- Austrian-Swedish
The story
Lise Meitner was born in Vienna in 1878 to a Jewish family. She spent three decades in Berlin, where she became the first woman university professor of physics in Germany and led the physics section of the Kaiser Wilhelm Institute for Chemistry, working closely with the chemist Otto Hahn. In 1922 she discovered what is now called the Auger-Meitner effect. From 1934 she, Hahn and Fritz Strassmann bombarded uranium with neutrons, trying to understand a confusing mix of radioactive products they believed were new elements heavier than uranium.
Nazi Germany's annexation of Austria in March 1938 left Meitner stateless and in danger. On 13 July 1938, with help from the Dutch physicist Dirk Coster, she slipped across the Dutch border carrying two small suitcases, and she soon settled in Stockholm. In December Hahn wrote to her that he and Strassmann had found barium, an element about 40 per cent lighter than uranium, among the products. As chemists they trusted the result but could not explain it.
Over Christmas 1938 Meitner's nephew, the physicist Otto Robert Frisch, joined her at Kungälv in Sweden. Walking through snowy woods, they sat on a tree trunk and calculated on scraps of paper. Using the idea that a nucleus behaves like a liquid drop, they reasoned that a uranium nucleus could stretch and divide in two. Meitner then worked out that the two fragments together would weigh about one-fifth of a proton mass less than the original nucleus, which by Einstein's formula E = mc² matched the roughly 200 million electron volts the fragments would carry. Everything fitted.
Back in Copenhagen, Frisch confirmed the process experimentally on 13 January 1939 by detecting the energetic fragments. Borrowing a term from biology, where cells divide by fission, he gave the process its name, and their joint note appeared in Nature on 11 February 1939. Niels Bohr, on hearing the explanation, exclaimed at how foolish everyone had been not to see it.
The 1944 Nobel Prize in Chemistry went to Hahn alone, although Meitner was nominated 49 times for Nobel Prizes in physics and chemistry. Later historians, using the opened Nobel archives, judged her exclusion unjust. She received many other honours, and in 1997 element 109 was named meitnerium after her. Her explanation of fission remains the foundation of nuclear physics and nuclear energy.
Why it matters
Meitner and Frisch's explanation of fission opened the way to nuclear energy, which today supplies a significant share of the world's low-carbon electricity, and to new tools in medicine and research.
About Lise Meitner
Nuclear physicist who co-discovered nuclear fission; refused to work on the atomic bomb. Element 109 (meitnerium) named for her.
More about Lise Meitner
- Lise Meitner discovered what is now the Auger–Meitner effectIn 1922 Lise Meitner explained why atoms emit electrons with signature energies. The process is now called the Auger–Meitner effect after her and Pierre Auger.
- Lise Meitner became Germany's first woman physics professorIn 1926 Lise Meitner became the first woman university professor of physics in Germany, after starting her Berlin career as an unpaid guest in a converted woodshop.
- Lise Meitner isolated and named protactiniumWorking almost alone during the First World War, Lise Meitner isolated the long-lived isotope of element 91 by December 1917 and named the element protactinium.
- Lise Meitner refused to help build the atomic bombAlthough her work explained nuclear fission, Lise Meitner declined an invitation to join the British mission to the Manhattan Project, saying she would have nothing to do with a bomb.
- Lise Meitner served as an X-ray nurse in World War IDuring the First World War, Lise Meitner trained as an X-ray technician and served with the Austrian Army as an X-ray nurse on the Eastern and Italian fronts.
Sources
- Lise Meitner Wikipedia
- Otto Robert Frisch Wikipedia
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.