Stephen William Hawking born 8 January 1942 ) is an English theoretical physicist , cosmologist , author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge .
Stephen William Hawking CH , CBE , FRS , FRSA ( i / ˈstiːvən ˈhɔːkɪŋ / ; born 8 January 1942 ) is a British theoretical physicist , cosmologist , author and Director of Research at the Centre for Theoretical Cosmology within the University of Cambridge .