While levitating, [Stephen Hawking], who has been in a wheelchair for nearly four decades, was spun twice -- pirouetting like a "gold medal gymnast," a crew member said. Someone else floated an apple in the air alongside him in an allusion to Isaac Newton, whose esteemed chair Hawking now holds at Cambridge.

"It was amazing. ... I could have gone on and on. Space, here I come," Hawking said afterward, once again sitting slightly twisted in his wheelchair. His "voice" is actually the product of a synthesizer he dictates to using eye twitches.