Edwin Powell Hubble

Edwin Powell Hubble 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. Slipher 's discovery that galaxies had strong shifts to the red end of their spectra, Hubble used the Cepheids 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 law . 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 (1889–1953) US astronomer. In 1925, he published his classification of galaxies and his discovery that spiral nebulae were resolvable as independent star systems. Using the telescope at Mount Wilson Observatory, he measured the distance to the Andromeda Galaxy. He attributed the red shift of the spectral lines of galaxies to their recession, and hence to the expanding Universe. In 1929 he proposed a linear relation between the distance of a galaxy from Earth and their velocity of recession (Hubble's law). See also galaxy; nebula