Allan Sandage (1926-2010)

摘要

Allan Sandage spent long nights leading observational cosmology until studies of the cosmic microwave background led to a new dawn. For 60 years, he surveyed and measured the universe. He died on 13 November at age 84. His fascination with stars began as a youth in Iowa and led to his study of physics at the University of Illinois and a Ph.D. in astronomy from the California Institute of Technology (CalTech) in 1953, where he was a student of Walter Baade. He joined the Carnegie Observatories in Pasadena (where he remained), became Edwin Hubble's assistant a year before Hubble's sudden death, and inherited Hubble's program to determine the size and age of the universe. Hubble had used the magnitudes of the brightest stars in galaxies to determine their distances. Sandage realized that many of these were actually tight groups of bright stars, together brighter than any star in the Milky Way, and this doubled the distances estimated to those galaxies. Thus began his main work improving distance measurements to determine the age of the universe.