United States of America · Science / Astronomy. Chronological records rendered directly from the World History Database.
Beginning in 1914, Harlow Shapley began a series of studies of globular clusters, published in about 40 scientific papers. He examined the RR Lyrae variables in the clusters (which he assumed were cepheid variables) and would use their period-luminosity relationship for distance estimates
Harlow Shapley uses Cepheids to place initial constraints on the size and shape of the Milky Way, and of the placement of our Sun within it
Discovers a class of variable stars known as cephids existing outside our own galaxy
Hubble establishes the distance to Cepheid variables in the Andromeda Galaxy, showing that Andromeda lies beyond the Milky Way and helping settle the Island Universe debate.
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