Miss Leavitt's Stars

In Miss Leavitt's Stars: The Untold Story of the Woman Who Discovered How to Measure the Universe, Henrietta Swan Leavitt, a woman scientist in a field and time dominated by men, is the central and enigmatic figure in the quest to determine the distances of stars from the Earth—and thus to help define the shape of the universe itself. Author George Johnson begins with an explanation of the ways that distant objects, over the ages, have been measured, and skillfully extrapolates that information to the problem of measuring the distance of stars from the Earth.

Born in 1868, often ill, and deaf, Leavitt, an 1892 Radcliffe graduate, began working in 1893 at the Harvard Observatory as a “computer”—a staff member responsible for the unglamourous and tedious work of interpreting, classifying, and recording astronomical data. Nonetheless, from 1904 to 1908, she observed that stars whose brightness varied tended to be brighter the longer their period (or “blink”). Johnson explains how, using the brightness to gauge the star's distance, the distance of the star from the Earth can be measured. These stars—“Miss Leavitt's stars”—are still important tools in astronomical measurement.

Johnson continues by taking the reader through the results of Leavitt's discovery after her death in 1921, and shows how her “yardstick” was used by other, more famous astronomers, such as Edwin Hubble, to help determine the existence of other galaxies beyond the Milky Way, the expanding nature of the universe, and the size, shape, and age of the universe itself.