3. Cecilia Payne Discovered the Composition of Stars
Cecilia Payne was born into a wealthy family in 1900 and attended prestigious schools including Cambridge University, where she became fascinated by astronomy. In fact, she felt that the study of astronomy completely turned her worldview on its head. However, because Cambridge did not grant degrees to women until 1948, Cecilia Payne had to travel to the United States in order to complete doctoral studies at Harvard. In 1925, she proposed in her doctoral thesis that stars were made of hydrogen and helium. She even went so far as to show which class individual stars belong to based on the spectrum that they emitted rather than on the estimated temperature.
Her dissertation was considered by some astronomers to be the most brilliant contribution to astronomy to date. However, at the time her claims were deemed to be spurious yet went on to be proved entirely correct. Because she was a female, her work was primarily attributed to fellow astronomer Henry Norris Russell.
Payne went on to create a survey of millions of stars; the analyses of these stars were used to develop a theory of stellar evolution, or how stars are formed, “live,” and “die.” Her work was so significant that it laid the foundation for all later work done on stars. Perhaps even more significantly, with her profound dissertation, women scientists began to enter mainstream academia.