Born in Philadelphia in 1928, Rubin studied deep space and worked with other scientists to develop better telescopes and instruments that could collect more detailed data about the universe. In 1968, according to a Nova documentary, she started observing the Andromeda galaxy and collecting the data that would upend science's understanding of our universe.
Her primary claim to fame came after she observed how quickly galaxies rotate.
"The presumption was that the stars near the center of a galaxy would be orbiting very rapidly, and stars at the outside would be going very slowly," Rubin said in 1987.
But Rubin realized that she was observing that outer stars were moving quickly, contrary to expectations. They weren't flying out of orbit, which meant that there had to be more mass scientists weren't observing — confirming the concept of dark matter.