04/07/1865 American astronomer Henrietta Swan Leavitt is born
Henrietta Leavitt & the Human Computers: Great Minds
What did Henrietta Swan Leavitt do for astronomy
Henrietta Leavitt: Unsung Heroine in Science
She discovered the relationship between the luminosity and the period of Cepheid variable stars. She studied variable stars in the Magellanic Clouds. Her work allowed astronomers to measure the distance between the Solar system and faraway galaxies. Edwin Hubble later used it to prove that the universe is expanding.