"He Went Where Star Trek Feared to Tread" --Three Influences That Shaped Stephen Hawking's Cosmos (WATCH Today's 'Galaxy' Stream)

The reaction among physicists yesterday to Hawking's death is "just profound shock and sadness," says Malcolm Perry, a Cambridge theoretical physicist who was a student of Hawking's in the early 1970s. "He was a truly extraordinary man," says Roger Penrose,...