Edwin Hubble was an American astronomer who played a crucial role in establishing the field of extragalactic astronomy and is widely considered the leading observational cosmologist of the 20th century.
Hubble was born to John Powell Hubble, a businessman in the insurance industry, and Virginia Lee James, a homemaker who managed the household while John was frequently away on business. Raised in a family of eight children, Hubble won a scholarship to the University of Chicago in 1906. There, he served as a student laboratory assistant for physicist Robert Millikan, a future Nobel Prize winner, and graduated in 1910.
Awarded a Rhodes Scholarship from Illinois, Hubble spent three years at the University of Oxford, earning a B.A. in jurisprudence, a subject chosen at his father's insistence. After his father's death in 1913, Hubble had the opportunity to pursue a scientific career. Returning to the United States in 1913, he taught high school in Indiana for a year before entering the University of Chicago for graduate studies in astronomy. Hubble conducted his observational research at the Yerkes Observatory in Wisconsin, using a powerful 24-inch reflector telescope.
In a stroke of good fortune, Hubble completed his graduate studies just as the director of the Mount Wilson Observatory in California, George Ellery Hale, was seeking new staff. Hubble accepted a job offer to work with the observatory's 100-inch Hooker telescope, the most powerful in the world at the time. However, World War I interrupted his plans, and he enlisted in the U.S. Army. Hale held the position open for Hubble until the war's end, during which Hubble served in France, eventually rising to the rank of major.
Upon returning to Mount Wilson, Hubble shifted his focus from studying reflection nebulae within the Milky Way to investigating spiral nebulae, particularly the Andromeda Nebula. In 1923, he discovered Cepheid variable stars in Andromeda, allowing him to estimate its distance. This led to the realization that the Andromeda Nebula was a galaxy separate from the Milky Way. Hubble's subsequent research on redshifts and distances of galaxies provided crucial evidence for the expansion of the universe.
In 1929, Hubble published his first paper on the redshift-distance relationship, suggesting a linear correlation. Collaborating with Milton Humason, he presented convincing evidence in 1931 that supported the linear relationship and implied an expanding universe. This finding aligned with the emerging theory of an expanding universe based on general relativity.
Hubble continued his work at Mount Wilson, contributing significantly to the establishment of extragalactic astronomy in the 1920s and '30s. He published his influential book, "The Realm of the Nebulae," in 1936, outlining his approaches to extragalactic astronomy. Hubble's research laid the foundation for future astronomers, particularly at Mount Wilson and the Palomar Observatory.
During World War II, Hubble served in an administrative role at the Aberdeen Proving Grounds in Maryland. He died in 1953 due to a cerebral thrombosis and was survived by his wife, Grace, with whom he had no children.
