Edwin Hubble

Lore & Background

Edwin Hubble was an American astronomer whose work fundamentally reshaped humanity’s understanding of the cosmos. He demonstrated that objects previously classified as “nebulae”—thought to be mere clouds of dust and gas within the Milky Way—were in fact independent galaxies far beyond our own. To measure these immense distances, Hubble applied the relationship between a Cepheid variable star’s luminosity and its pulsation period, a discovery made by Henrietta Swan Leavitt. In 1929, he confirmed that a galaxy’s recessional velocity increases with its distance from Earth, a principle now called Hubble’s law, which implies the universe is expanding. This built on earlier evidence from Vesto Slipher, who had observed strong red shifts in the light from many nebulae, indicating high recession velocities. Hubble also developed a system for classifying galaxies by their appearance, known as the Hubble sequence. His career was spent at the Mount Wilson Observatory, where he was recruited by George Ellery Hale, and he later became the first astronomer to use the giant Hale Telescope at Palomar Observatory. The Hubble Space Telescope was named in his honor, and a model of it is displayed in his hometown of Marshfield, Missouri.

Reader's Guide

Edwin Hubble’s career began with athletic distinction, leading his university basketball team to a conference title and excelling in track and field before shifting to academic pursuits. After earning a bachelor’s degree in mathematics, astronomy, and philosophy, he studied law at Oxford as a Rhodes Scholar to fulfill a promise to his father, later teaching high school subjects and coaching basketball. He eventually returned to astronomy, earning a doctorate with a dissertation on faint nebulae. At Mount Wilson Observatory, Hubble used the relationship between a Cepheid variable’s luminosity and pulsation period—discovered by Henrietta Swan Leavitt—to prove that many objects once classified as nebulae were actually galaxies beyond the Milky Way, establishing extragalactic astronomy. He then confirmed that a galaxy’s recessional velocity increases with its distance, a proportional relationship later called Hubble’s law, which implies the universe is expanding. This built on earlier evidence of redshift from Vesto Slipher. Hubble also developed a classification system for galaxies that remains a standard tool. During World War II, he directed ballistics research, inventing a high-speed clock camera to study projectiles. The Hubble Space Telescope was named in his honor.

Did You Know?

• Hubble helped the University of Chicago's basketball team win its first Big Ten Conference title in the 1907–1908 season.
• He taught Spanish, physics, and basketball at New Albany High School in Indiana before earning his Ph.D.
• During World War II, Hubble served as Chief of the External Ballistics Branch at Aberdeen Proving Ground and received the Legion of Merit.
• He became the first astronomer to use the 200-inch Hale Telescope at Palomar Observatory shortly before his death.