Hubble, Edwin Powell


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Hubble, Edwin Powell,

1889–1953, American astronomer, b. Marshfield, Mo. He did research (1914–17) at Yerkes Observatory, and joined (1919) the staff of Mt. Wilson Observatory, Pasadena, Calif., of which he became director. Building on V. M. SlipherSlipher, Vesto Melvin
, 1875–1969, American astronomer, b. Mulberry, Ind. From 1901 he was at Lowell Observatory, Flagstaff, Ariz., where he served as director (1917–54).
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's discovery that galaxies had strong shifts to the red end of their spectra, Hubble used the stars known as Cepheid variablesCepheid variables
, class of variable stars that brighten and dim in an extremely regular fashion. The periods of the fluctuations (the time to complete one cycle from bright to dim and back to bright) last several days, although they range from 1 to 50 days.
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 in nearby galaxies to demonstrate that they lie far beyond the Milky Way. Because of an incorrect understanding of the Cepheids, this distance was vastly increased years later. He also suggested that the clusters of galaxies are distributed almost uniformly in all directions, although more recent studies show that clusters are combined into huge superclusters of galaxies: at this new level, however, the distribution appears to be even. He was the first to offer observational evidence to support the theory of the expanding universe, presenting his findings in what is now known as Hubble's lawHubble's law,
in astronomy, statement that the distances between galaxies (see galaxy) or clusters of galaxies are continuously increasing and that therefore the universe is expanding.
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. With Milton Humason, Hubble classified the different types of galaxies including irregular galaxies, three types of spirals and barred spirals, and elliptical galaxies. Included in his writings are A General Study of Diffuse Galactic Nebulas (1926), Extra-Galactic nebulas (1927), Spiral Nebula as a Stellar System (1929), The Realm of the Nebulas (1936), and The Observational Approach to Cosmology (1937).

Bibliography

See biography by G. E. Christianson (1995).

Hubble, Edwin Powell

 

Born Nov. 20, 1889, in Marsh-field, Mo.; died Sept. 28, 1953, in San Marino, Calif. American astronomer. Member of the National Academy of Sciences in Washington D.C. (from 1927).

From 1914 to 1917, Hubble worked at the Yerkes Observatory, and from 1919 at the Mount Wilson Observatory. His main works were devoted to the study of galaxies. In 1922, Hubble proposed a classification of observable nebulas into extragalactic nebulas (galaxies) and galactic nebulas (gas-dust nebulas). In the period 1924–26, he was able to detect on photographs the stars of which the galaxies closest to us consist and thus prove that they are stellar systems similar to our galaxy. In 1929, Hubble established the relationship between the red shift of galaxies and the distance to them (Hubble’s law).

WORKS

“A General Study of Diffuse Galactic Nebulae.” The Astrophysical Journal, 1922, vol. 56, no. 3.
The Observational Approach to Cosmology. Oxford, 1937.
The Realm of the Nebulae. New Haven-London, 1936.