Edwin Hubble dies. Hubble was destined for success: six feet tall, handsome, intelligent, and confident, he excelled in everything he did. He was a champion in track and field, basketball, water polo, and boxing. But Edwin Powell Hubble was above all an American astronomer who played a crucial role in founding the fields of extragalactic astronomy and observational cosmology. Hubble demonstrated that many objects previously thought to be clouds of dust and gas and classified as “nebulae” were actually galaxies beyond the Milky Way. He used the strong direct relationship between the luminosity and pulsation period of a classical Cepheid variable (discovered in 1908 by Henrietta Swan Leavitt) to scale galactic and extragalactic distances. Hubble confirmed in 1929 that a galaxy’s recession velocity increases with its distance from Earth, a behavior that became known as Hubble’s law, although it had been proposed two years earlier by Georges Lemaître. Hubble’s law implies that the universe is expanding. A decade earlier, American astronomer Vesto Slipher had provided the first evidence that the light from many of these nebulae was strongly redshifted, indicative of high recession velocities. Hubble is best known for the Hubble Space Telescope, which bears his name and of which a model is on display in his hometown of Marshfield, Missouri.
