Word: cepheid
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Dates: during 1930-1939
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Super-Galaxies & Cepheids. Astronomer Harlow Shapley of Harvard, who loves to systematize the universe, was the first man to find that stellar galaxies like the Milky Way, each containing billions of stars, were sometimes huddled in groups which he calls "super-galaxies." Last week he reported the discovery, made by astronomers at Harvard's observatory in South Africa, of two new, far-off super-galaxies, each of which is about 1,000,000 light-years in diameter (one light-year equals approximately six trillion miles). Another discovery, nearer home, concerned the Cepheid variables-a class of stars, mostly yellow...
...Cepheid variable stars, whose fluctuating light beams enable measurement of great interstellar distances, may prove also to hold important new clues to forces at work within the great island universes, or galaxies like our own Milky Way, Harlow Shapley, Director of the Observatory, recently told the National Academy of Sciences...
Star photographs made at the Harvard astronomy station in South Africa reveal an unusual distribution of Cepheid variable stars in the Small Magellanic Cloud, neighbor star system of the Milky Way. There is a "peculiar concentration" of the larger, longer-period Cepheid variable stars in regions where the star population is dense, Shapley said. Cepheids fluctuate in brightness in periods ranging from a few hours to about fifty days; their mass is four to five times that...
Shapley said that the "newly found prenomenon" of Cepheid distribution may prove to be "an indicator of gravitational potential throughout a galaxy." However, there may be another, alternative explanation of the peculiar distribution, involving the distribution of various chemical substances in the Magellanic Cloud, Shapley said. There is a possibility that the chemical distribution of the cloud is such that the large stars were found in densely populated star areas...
...meeting of the International Astronomical Union in Stockholm last week, Dr. Shapley reported on 2,000 Cepheid variables (giant stars which fluctuate regularly in brightness) at considerable distances from the Milky Way's central plane. These have the effect of stretching the galaxy's "vertical" diameter to about 80,000 light-years.** The diameter across the disk is put at 100,000 lightyears. Thus, the flattish lens of the Milky Way is enclosed in a globe of stars, and the galaxy's total shape resembles a pumpkin...