"Black holes ain't as black as they are painted. They are not the eternal prisons they were once thought. Things can get out of a black hole, both to the outside, and possibly, to another universe. So,…"

"The greatest achievement of mankind is to understand the universe."

"I think [contacting an alien civilization] would be a disaster. The extraterrestrials would probably be far in advance of us. The history of advanced races meeting more primitive people on this planet…"

"I deal in tough mathematical questions every day, but please don't ask me to help with Brexit."

"We are all time-travelers, heading into the future at the rate of one second per second."