Vera Rubin saw something unusual in galaxies: outer stars orbit just as quickly as those in the center. She surmised that each galaxy must contain more mass than meets the eye. It was the first observational evidence of dark matter, which today is one of the most studied cosmology topics.
Maryam Mirzakhani was an Iranian mathematician and a professor of mathematics at Stanford University. Her research topics included Teichmüller theory, hyperbolic geometry, ergodic theory, and symplectic geometry.