Fifty years," I hackneyed, "is a long time." "Not when you're looking back at them," she said. "You wonder how they vanished so quickly.

To bring about destruction by overcrowding, mass starvation, anarchy, the destruction of our most cherished values, there is no need to do anything. We need only do nothing except what comes naturally, and breed. And how easy it is to do nothing

The fundamentalists deny that evolution has taken place; they deny that the earth and the universe as a whole are more than a few thousand years old, and so on. There is ample scientific evidence that the fundamentalists are wrong in these matters, and that their notions of cosmogony have about as much basis in fact as the Tooth Fairy has.

At two-tenths the speed of light, dust and atoms might not do significant damage even in a voyage of 40 years, but the faster you go, the worse it is--space begins to become abrasive. When you begin to approach the speed of light, hydrogen atoms become cosmic-ray particles, and they will fry the crew. ...So 60,000 kilometers per second may be the practical speed limit for space travel.

Self-education is, I firmly believe, the only kind of education there is.

Life would be impossible on such a planet. It wouldn't get enough heat and light, and if it rotated there would be total darkness half of every day. There wouldn't be any native inhabitants. You couldn't expect life - which is fundamentally dependent on light - to develop under such extreme conditions of light deprivation. Half of every axial rotation spent in Darkness! No, nothing could exist under conditions like that.

Mathematicians deal with large numbers sometimes, but never in their income.