Henrietta Swan Leavitt was an influential astronomer in the early twentieth century. She determined the distances among stars and galaxies over 100 light years away, which became known as Leavitt’s Law. Leavitt’s discovery was crucial to the progression of astronomy and foundational to our understanding of the universe and the placement of galaxies within the universe. 


Leavitt attended Oberlin College and later finished her studies at the Society for the Collegiate Instruction for Women (later known as Radcliffe College of Harvard University). During her senior year of college, Leavitt discovered an interest in astronomy and was later hired as a “computer” by Harvard College Observatory. Computers were in charge of studying the brightness of various stars via photographic plates. 


Leavitt is well known for her work involving Cepheid variables. She was very interested in the relationship between the luminosity, or brightness, of a star and its period, the amount of time it takes to brighten, dim, and then brighten again. She found that the brighter the star, the longer the period. Consequently, she determined the star’s distance from earth. This process proved to be the distance key and has shown to be vital to other astronomical advancements and our knowledge of the universe. 


In addition to Leavitt’s Law, she also discovered four novas and 2,400 variable stars, more than any other astronomer of her time. Leavitt was devoted to her work until the day she died. As a pioneer in her field, Leavitt set the standard that many other astronomers have since built upon, discovering our ever-expanding universe.


Leavitt was the daughter of a pastor. Growing up, Leavitt spent a lot of time in the local church with her father. She had a strong foundation of faith and an understanding of duty, justice, and loyalty. One of Leavitt’s professors said that Leavitt appreciated the good she found in others and found meaning and beauty in life.