Henrietta Leavitt (astronomer for the law of variable stars)

Henrietta Leavitt was an astronomer in the early 20th century who studied a type of star called Cepheid variables. She discovered that these stars' brightness fluctuations are directly related to their true luminosity—their actual brightness. This relationship, known as Leavitt’s Law, allowed astronomers to measure the distance to faraway galaxies by observing Cepheid variables. Her work was fundamental in expanding our understanding of the universe's scale, helping us see how far celestial objects are from Earth and paving the way for modern cosmology.