Edwin Hubble received his Ph.D. from the University of Chicago in 1917. His dissertation, titled “Photographic Investigations of Faint Nebulae,” examined faint, cloudy-looking astronomical objects and helped launch the research that later made him famous.
Hubble hurried to finish the doctorate after the United States entered World War I. Soon afterward, he joined the U.S. Army and served in the 86th Division, eventually reaching the rank of major. After the war, he spent a year at the University of Cambridge before beginning his major observational work at Mount Wilson Observatory.
A common mix-up is confusing Hubble’s doctorate with his later Oxford studies. He earned a law-related degree at Oxford as a Rhodes Scholar, but his Ph.D. came earlier from Chicago. His doctoral work also predates his landmark 1920s observations showing that many “spiral nebulae” were actually distant galaxies beyond the Milky Way.