Stephen Hawking left memorable impact through TV cameos

Stephen Hawking, who died early Wednesday at the age of 76, was perhaps the most exclusive guest star in television history. He appeared on - or rather graced - both "The Simpsons" and "The Big Bang Theory" a number of times. Cameos on both were invariably preceded by national news stories both here and in the United Kingdom. Outtakes became viral, and remain viral to this day.