George Efstathiou (born 1955), British cosmologist and professor of astronomy at the University of Oxford, England. Efstathiou is a leading cosmologist and his work is focused on how galaxies formed and evolved into the large-scale structure of the Universe that we observe in the sky. He is seen silhouetted against a map of a portion of the southern sky which he created together with other astronomers. The map plots the position of 2 million galaxies at an average distance of 1500 million light years from the Earth. Data from 200 photographic plates were gathered to compose this map in a project that lasted six years.