"The human race is a single genetic stock, and we are all brothers and sisters. It's time that we started to act like it."

"I don't think the human race will survive the next thousand years, unless we spread into space."

"It is a matter of common sense to take a method and try it. If it fails, admit it frankly and try another. But above all, try something."

"I believe that there is no heaven or afterlife. That is a fairy story for people afraid of the dark."

"The universe is a very strange place, and I'm still trying to figure it out."