Edwin Hubble was one of the most important astronomers of the 20th century. He played a key role in establishing the field of extragalactic astronomy and is best known for his work on the expansion of the universe.
Hubble was born in Marshfield, Missouri, on November 20, 1889. He studied at the University of Chicago, where he earned a bachelor’s degree in 1910 and a doctorate in 1917. After serving as a research assistant at Mount Wilson Observatory in California, he joined the staff of the Carnegie Institution’s Department of Terrestrial Magnetism in Washington, D.C., in 1919.
In 1925, Hubble published a paper proposing that some nebulous patches seen in the night sky were actually distant galaxies like our own Milky Way. This groundbreaking work established extragalactic astronomy as a distinct field of study. Hubble continued to study galaxies and their distances from Earth throughout his career. In 1929, he discovered that there is a linear relationship between a galaxy’s distance from Earth and its velocity away from us due to the expansion of the universe. This discovery helped support Georges Lemaître’s theory that the universe began with an enormous explosion, later known as the Big Bang.
In 1931, Hubble was appointed director of Mount Wilson Observatory, where he oversaw construction of two powerful telescopes: The 100-inch Hooker Telescope (completed in 1917) and 200-inch Hale Telescope (completed in 1948). He used these telescopes to observe some of the most distant galaxies ever seen and to confirm that they are moving away from us at high speeds. His observations helped cement our understanding that we live in an expanding universe that started with a bang billions of years ago.
Hubble died on September 28, 1953, but his legacy continues to shape our understanding of cosmology today. The Edwin P