On November 20th, 2012, American astronomer Edwin Powell Hubble would have celebrated 123 years on Planet Earth. Hubble's discovery and development of the concept of an expanding universe has been described as the "most spectacular astronomical discovery" of the 20th century. As a tribute, the Hubble Space Telescope, deployed April 25, 1990, from US space shuttle Discovery, was named for him. The Hubble Space Telescope, with a 240-centimeter mirror, was to allow astronomers to see farther into space than they had ever seen from telescopes on Earth.