Lise Meitner explained nuclear fission with Otto Frisch after its discovery in 1938.
Otto Hahn and Fritz Strassmann found evidence that uranium bombardment produced barium. Meitner, then living in exile in Sweden, interpreted the result during a discussion with her nephew Otto Frisch. They concluded that the uranium nucleus had split and used Einstein’s mass–energy relation to explain the enormous energy release.
Frisch coined the term “fission” for the process. Meitner’s contribution was central to the physical interpretation, although she did not share Hahn’s 1944 Nobel Prize in Chemistry. That omission remains a frequently discussed episode in the history of nuclear physics.
Meitner was born in Vienna in 1878 and later worked at the Kaiser Wilhelm Institute in Berlin. Element 109, meitnerium, was named in her honor.