Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is generally regarded as one of the most important observational cosmologists of the 20th century. Hubble is known for showing that the recessional velocity of a galaxy increases with its distance from the earth, implying the universe is expanding. Known as "Hubble's law", this relation had been discovered previously by Georges Lemaître; a Belgian priest/astronomer who published his work in a less visible journal. There is still much controversy surrounding the issue and some argue that it should be referred to as "Lemaître's law" although this change has not taken hold in the astronomy community.
Hubble is also known for providing substantial evidence that many formerly known "nebulae" were actually galaxies beyond the Milky Way. American astronomer Vesto Slipher provided the first evidence to this argument almost a decade before.
Hubble supported the Doppler shift interpretation of the observed redshift that had been proposed earlier by Slipher, and that led to the theory of the metric expansion of space. He tended to believe the frequency of any beam of light could, by some so far unknown means, be diminished ever stronger, the longer the beam travels through space.
Discovered by the Indiana Asteroid Program, Goethe Link Observatory, University of Indiana. This program was conceived and directed by F. K. Edmondson; the plates were blinked and measured astrometrically by B. Potter and, following her retirement, by D. Owings; and the photometry was performed under the direction of T. Gehrels. During the years 1947-1967, in which the plates were exposed, a large number of people participated in various aspects of the program.
At the annual meeting of 1951-01-12, Dr. Hubble was elected an Honorary Member of the Royal Astronomical Society of Canada. He wrote back, "Please convey to the National Council of the Royal Astronomical Society of Canada my deep appreciation of their proposal to nominate me for consideration as an Honorary Fellow. If elected, I would accept the honor with pleasure and pride."