Joseph Ivor Silk FRS (born 3 December 1942) was the Savilian Chair of Astronomy at the University of Oxford from 1999 to September 2011. He was educated at Tottenham County School (1954-1960) and went on to study Mathematics at the University of Cambridge (1960-1963). He gained his PhD in Astronomy from Harvard in 1968. Silk took up his first post at Berkeley in 1970, and the Chair in Astronomy in 1978.