Henrietta Swan Leavitt

Uncommon card · No. 180949

Henrietta Swan Leavitt (; July 4, 1868 – December 12, 1921) was an American astronomer. Her discovery of how to effectively measure vast astronomical distances led to a shift in the understanding of the scale and nature of the universe. A graduate of Radcliffe College, she worked at the Harvard College Observatory as a human computer, tasked with measuring photographic plates to catalog the positions and brightness of stars. This work led her to discover the relation between the luminosity and the period of Cepheid variables. Leavitt's discovery provided astronomers with the first standard candle with which to measure the distance to other galaxies. Before Leavitt discovered the period–luminosity relationship for Cepheid variables (sometimes referred to as Leavitt's Law), the only techniques available to astronomers for measuring the distance to a star were based on stellar parallax. Such techniques can only be used for measuring distances out to several hundred light years. Leavitt's great...

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