Tell me about Henrietta Swan Leavitt

Henrietta Swan Leavitt (1868–1921) was an American astronomer whose work fundamentally changed our understanding of the universe [1, 3].

Working at the Harvard College Observatory, Leavitt spent years measuring the positions and brightness of stars from photographic plates [3]. Her most significant achievement was the discovery of the relationship between the period and luminosity of Cepheid variable stars [2]. By observing that stars with longer pulsation periods were intrinsically brighter, she provided a "standard candle" that allowed astronomers to accurately measure vast distances across space [1, 2]. This breakthrough was essential in helping scientists determine the true scale and nature of the universe [1].