Edwin Hubble

Born on 20 November 1889 in Marshfield, Missouri, Edwin Hubble was an astronomer who confirmed that the Milky Way is just one of many galaxies and showed that galaxies’ redshifts increase with distance. Hubble studied at the University of Chicago and Oxford. Following his father’s wishes, he trained to become a lawyer. When his father died, Hubble followed his own interests and trained to become an astronomer. He earned a PhD in astronomy at Chicago in 1917 and served briefly in the US Army before joining the staff at Mount Wilson observatory in California. There, using a relationship discovered by astronomer Henrietta Swan Leavitt for determining the distance to certain variable stars, he found that Andromeda is another galaxy , not a star cluster within the Milky Way. Then in the late 1920s, Hubble discovered that galaxies’ recessional velocity increases roughly in proportion to their distance from Earth. Hubble’s discovery supported the notion of an expanding universe, which Georges Lemaître had proposed based on Albert Einstein’s theory of general relativity (though it should be noted that Hubble was skeptical of that interpretation). Hubble’s famous paper was published in 1929. He died in 1953. Thirty-seven years later, the space telescope that bears his name was launched with the task of, among other things, observing distant galaxies and helping to measure the Hubble constant . (Photo credit: Margaret Harwood, courtesy AIP Emilio Segrè Visual Archives)

Date in History: 20 November 1889