Edwin Powell Hubble (November 20, 1889 - September 28, 1953) was an American astronomer, noted for his discovery of galaxies beyond the Milky Way and the cosmological redshift.
Edwin Hubble was one of the leading astronomers of modern times and laid down the foundation upon which physical cosmology now rests.
Hubble's observations in 1923–1924 with the Hooker Telescope established beyond doubt that the fuzzy "nebulae" seen earlier with less sensitive telescopes were not part of our galaxy, as had been thought, but were galaxies themselves, outside the Milky Way.
He announced this discovery on January 1, 1925.
Hubble also devised a classification system for galaxies, grouping them according to their content, distance, shape, size and brightness.
Hubble was generally incorrectly credited with discovering the redshift of galaxies.