Edwin Hubble was an American astronomer born on November 20, 1889. He is best known for his groundbreaking work in the field of astronomy, particularly for demonstrating that the universe is expanding. Hubble's observations of distant galaxies led to the formulation of Hubble's Law, which states that the farther away a galaxy is, the faster it is moving away from us. Hubble played a crucial role in the development of modern cosmology. His work helped to establish the existence of other galaxies beyond our own, the Milky Way, and he contributed to the understanding of the universe's structure and evolution. Hubble passed away on September 28, 1953.