“Never fire a laser at a mirror. ”

“I'd visit the near future, close enough that someone might want to talk to Larry Niven and can figure out the language; distant enough to get me decent medical techniques and a ticket to the Moon.”

“I myself have dreamed up a structure intermediate between Dyson spheres and planets. Build a ring 93 million miles in radius - one Earth orbit - around the sun. If we have the mass of Jupiter to work with, and if we make it a thousand miles wide, we get a thickness of about a thousand feet for the base.And it has advantages. The Ringworld will be much sturdier than a Dyson sphere. We can spin it on its axis for gravity. A rotation speed of 770 m/s will give us a gravity of one Earth normal. We wouldn't even need to roof it over. Place walls one thousand miles high at each edge, facing the sun. Very little air will leak over the edges.Lord knows the thing is roomy enough. With three million times the surface area of the Earth, it will be some time before anyone complains of the crowding.”

“We need to take command of the solar system to gain that wealth, and to escape the sea of paper our government is becoming, and for some decent chance of stopping a Dinosaur Killer asteroid.”

“Building one space station for everyone was and is insane: we should have built a dozen.”

“The dinosaurs became extinct because they didn't have a space program.”

“The human species really could have faced global thermonuclear war. During seventy years of Cold War we grew used to it.”

“The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!”

“Each nugget of information was fascinating. The world was full of new-found marvels and he wanted to share the excitement with everybody. They all did. They had a certain sense. It wasn't a sense of ennui or cynicism. It was . . . A sense of wonder.That was it. A sense of wonder, in the fine old original meaning of the word. They wondered at their world. Because when you did that, everything was wonder-full.”

“One mark of a good officer, he remembered, was the ability to make quick decisions. If they happen to be right, so much the better”

“Fear is the brother of hate.”