Nearly 1,200 people crowded Caltech's Beckman Auditorium, and hundreds more watched a simulcast in overflow areas Tuesday night as theoretical physicist Stephen Hawking gave a rare talk about his own early life, influences and passions.
In his familiar, computerized voice Hawking told the story, from his wheelchair, of his youth in WWII-era London. He spoke in the humorous, self-deprecating and wry British style Hawking has become known for. "Can you hear me?" Hawking joked as he opened his talk.
"There's nothing like a eureka moment of discovering something nobody knew before. I won't compare it to sex, but it lasts longer," he rapped later.
Paced by the silence between his sentences, interrupted only by small beeps from his computer, Hawking described how his father, a well-respected doctor who studied African diseases, wanted Hawking to go into medicine. "Biology was too descriptive and not sufficiently fundamental," he said.
Hawking went on to describe his intellectual trajectory from mathematics to cosmology to quantum gravity, the study of how small particles act near black holes. The latter helped galvanize Hawking's theories on space, time and the size of the universe.
In the audience were former students of Hawking's, admirers who had waited hours to get good seats, and even Bill Nye the Science Guy.
"He accepts his physical limitations in a way you and I can't imagine," Nye said about his impression of Hawking.
Nye spent time with Hawking over dinner last February in Cambridge when he went to present the physicist with the Cosmos Award. He remembers Hawking asking for foie gras for dinner.
"He was so engaged," Nye recalled of the impressions Hawking made on him. Asked how a man who speaks very slowly through a computer can be engaging in conversation, he said, "When you hear that voice, you stop."
Also there to see Hawking Tuesday night was Alan Yuille, UCLA Professor of comparative neuropsychology and artificial intelligence. Hawking advised Yuille on his PhD at the University of Cambridge in the late 1970's.
Yuille recalled Hawking's unconventional teaching methods as an adivser. Hawking would bring amazing visitors to campus, and he liked to take his students into the tea room to listen and observe intellectual conversations, Yuille said.
He said around that time Hawking's ALS, a motor neural disease that destroys voluntary muscle movement, was getting worse. "His grad students became his auxiliary nurses," Yuille recalled, adding that he would take care of Hawking's son Robert.
Yuille remembered a funny moment when Hawking, who broke ground on the science of black holes, went to see the opening of Disney's 1979 film "The Black Hole." "[Hawking's son] Robert saved the day, telling the producers that his father liked the film. The physics was doubtful," Yuille said.
At one point in his talk, Hawking reflected on the fears he had as his ALS set in during his graduate work, admitting he was unsure he would survive to finish his PhD.
"When you are faced with the possibility of early death," he said, "it makes you realize life's worth living, and there are lots of things you want to do."
The Hawking comedy hour continued into the Q & A session afterward. Caltech sophomore Shiyi Teresa Liu asked Hawking about a stunt he once did to prove time travel from the future to the past is impossible, in which he created invitations for time travelers from the future. Liu asked Hawking:
Suppose you hold your party and time travelers DO show up; but soon after your party you suddenly change your mind and destroy all the letters. What will happen? Will the time travelers who showed up at your party suddenly disappear into the future when you destroy the letters? If so, haven't you just changed the future in the past?
Hawking: Even if I destroyed all the invitations, the television program is on YouTube, so time travelers from the future would know about the party. Of course, they would also know that nobody came. Maybe that's why they didn't turn up.