Curiosity is a self-driven motivation to explore and to learn. Learning is like... you know, you have to take your medicine. And that is what it has become. And that's unfortunate.

Where ignorance lurks, so too do the frontiers of discovery and imagination

I don't want to go back into space for military reasons, but the economic driver still remains. And so it's a matter of people understanding how that economic driver is revealed with healthy investments on the space frontier.

The history of exploration has never been driven by exploration. But Columbus himself was a discoverer. So was Magellan. But the people who wrote checks were not. They had other motivations. And there's Columbus - he couldn't even get Italy to pay for his voyage so he has to go to Spain.

There is a theorem that colloquially translates, You cannot comb the hair on a bowling ball. ... Clearly, none of these mathematicians had Afros, because to comb an Afro is to pick it straight away from the scalp. If bowling balls had Afros, then yes, they could be combed without violation of mathematical theorems.

If you're interested in something, that's all that matters. You'll spend more time doing it, that than anything else, and possibly more time doing it than anybody else.

With no gravitational force to work against, your body not only doesn't need the same amount of muscle and bone, it starts breaking them down. As on Earth, so in space: use it or lose it. And exercise may not solve the problem.