Shapley, Harlow (1885-1972), a United States astronomer. His studies of stars in globular clusters and of Cepheid variable stars led to a new understanding of the structure of the universe. From these studies he determined the size and shape of the Milky Way and placed the solar system far from the galaxy's center. He introduced the theory that the Cepheid variable stars undergo changes in brightness because they pulsate, alternately growing and shrinking in size. He also developed a method of determining the physical properties of eclipsing binaries.
Shapley was born in Nashville, Missouri. After attending the University of Missouri, he received a Ph.D. from Princeton in 1913. He was a staff astronomer at Mount Wilson Observatory in California and then directed the Harvard College Observatory, 1921-52. Shapley wrote numerous technical and popular books. Through Rugged Ways to the Stars (1969) is his autobiography.