Did you know! Emmy Noether (1882-1935) She devised a mathematical principle, called Noether's theorem, which became a foundation stone of quantum physics. Her calculations helped Einstein formulate his general theory of relativity. "It is really through her that I have become competent in the subject," he admitted.

Did you know! Lise Meitner (1878-1968) In 1938, after she escaped from the Nazis to Sweden, she carried out the key calculations that led to the discovery of nuclear fission. Her collaborator, Otto Hahn, who stayed behind in Germany, was the sole recipient of the Nobel Prize in chemistry in 1944. In 1997 Meitner was finally honored when element 109 was named meitnerium.

Did you know! Cecilia Payne-Gaposchkin (1900-1979) In her 1925 Ph.D. thesis—described by the noted astronomer Otto Struve in 1960 as "the most brilliant . . . ever written in astronomy"—she proposed that all stars are made mostly of hydrogen and helium. Astronomers dismissed her observations until four years later, when they were confirmed by a man. She was the first woman to become a professor of science at Harvard.