Edwin Hubble, born in Marshfield, Missouri, on November 20, 1889, made as great an impact on the astronomy of the twentieth century as Nicholas Copernicus did in the sixteenth century. At the time of Hubble's birth, no galaxies outside our own were known to exist. His work increased the scale of the known universe a billion-fold.

Hubble attended the University of Chicago where he was influenced by physicist Robert A. Millikan and astronomer George Hale (1868-1939). After receiving a degree in mathematics and astronomy, Hubble went to Oxford University in England where he studied law. He returned to the United States in 1923 and opened a law office in Louisville, Kentucky. This career evidently was not fulfilling, for in 1914, he returned to the University of Chicago to work at the Yerkes Observatory where he made a meticulous study of the mysterious fuzzy patches of light called nebulae.

The nature of these...