Stephen Hawking smiles during a 2002 symposium in honor of his 60th birthday at the University of Cambridge. Hawking has died at 76.

Stephen Hawking smiles during a symposium in honor of his birthday at the University of Cambridge Jan. 11, 2002 in Cambridge, England. Hawking turned 60-years-old on Jan. 8, 2002 and is the Lucasian Professor of Mathematics, a post once held by Sir Isaac Newton.