LEAVITT, HENRIETTA SWAN (4 July 1868–12 December 1921), American astronomer credited with the discovery of the period-luminosity relation of Cepheid-variable stars (“Leavitt’s law”), which allowed astronomers to accurately measure the distances to far-flung galaxies for the first time. Although overlooked in her day, Leavitt has been posthumously honored as “the woman who discovered how to measure the universe.”
After graduating from Radcliffe College in 1892, Leavitt began working at the Harvard College Observatory as a “human computer,” one of a group of women hired to measure and classify stars photographed by the observatory. At the time women were not allowed to operate telescopes nor partake in theoretical work; female scholars were perceived by men to be better suited to detail-oriented and monotonous tasks. Nevertheless, through careful analysis of the photographic plates Leavitt discovered that the fluctuations in brightness of Cepheid-variable stars obeyed a regular cycle and that the brightness is determined by the variable’s actual luminosity. Leavitt’s law led to the calibration of the period-luminosity curve, which allows astronomers to determine the distance of star clusters and galaxies from Earth. In 1924 Edwin Hubble applied Leavitt’s law in measuring the distance to the Andromeda Nebula, which was instrumental to the discovery of other galaxies. While Hubble was honored with several awards and the naming of the Hubble Space Telescope, Leavitt’s indispensable contribution remained largely unrecognized; she was never formally promoted to a title above assistant.
In 2021 artist Anna Von Mertens addressed this historical lacuna by exhibiting a series of quilted works inspired by Leavitt’s life and her contributions to science. In her quilt diptych titled “The stars fading from view on the morning of Henrietta Leavitt’s birth, July 14, 1868, Lancaster, Massachusetts; The stars returning into view on the evening of Henrietta Leavitt’s death, December 12, 1921, Cambridge, Massachusetts” (2018) the two panels, each a blurry but minutely detailed woven view of the sky on the respective nights, are separated by a gulf of blank wall. Here Von Merten both honors Leavitt’s legacy and acknowledges the lamentable historical reality that the intervening life between the days of her birth and death is largely unknown and unremembered.
After Leavitt was posthumously honored by having a moon crater named after her, artist Aura Satz aptly criticized the gesture, noting, “The idea of women’s names being associated with imperceptible craters on the moon seemed an apt metaphor for women having a moment of slight visibility and then receding in the distance of history.”
Henrietta Swan Leavitt succumbed to cancer in 1921, quietly and unceremoniously passing away at the age of fifty-five.