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Astro*Dictionary by Michael Erlewine





1 article for "Shapley, Harlow"

Shapley, Harlow [Astro*Index]

(1885- ) American astronomer.

Born at Nashville, MO. Between 1915-1920, he used the 100-inch telescope at Mount Wilson for a study of globular clusters, which are immense, densly packed groupings of stars. About 100 such clusters were known at the time. Not evenly distributed over the sky, nearly one-third of them are concentrated within the boundaries of the constellation Sagittarius. Working with the Cepheid yardstick provided by Leavitt, he applied the period-luminosity curve to the Cepheid stars in each globular cluster, and (in 1914) calculated the distances of said clusters. He reasoned that if these globular clusters were arranged in a spherical manner about some point, that point would be the center of our galaxy. Dust clouds obscure our view of the center of the galaxy. Shapley's efforts prevailed, and the former concept which placed the Earth near the center of the galaxy was replaced with one which places our solar system near the periphery.

See also: ♦ Cepheid Variable ♦ Period-luminosity Relation ♦ Leavitt, Henrietta Swan ♦ Galactic Center ♦ Galactic Coordinates


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