There is a single light of science, and to brighten it anywhere is to brighten it everywhere.

To make discoveries, you have to be curious about why the universe is the way it is.

... you just can't differentiate between a robot and the very best of humans.

I believe in evidence. I believe in observation, measurement, and reasoning, confirmed by independent observers. I'll believe anything, no matter how wild and ridiculous, if there is evidence for it. The wilder and more ridiculous something is, however, the firmer and more solid the evidence will have to be.

Why this reluctance to make the change? We fear the process of reeducation.

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.

In life, unlike chess, the game continues after checkmate.