Most people don’t question the practice of eating meat. Many of these people care about animals and the environment, some deeply. But for some reason-force of habit, cultural norms, resistance to change-there is a fundamental disconnect whereby these feelings don’t translate into changes of behavior.

Every moment is as real as every other. Every 'now,' when you say, 'This is the real moment,' is as real as every other 'now' - and therefore all the moments are just out there. Just as every location in space is out there, I think every moment in time is out there, too.

Many different planets are many different distances from their host star; we find ourselves at this distance because if we were closer or farther away, the temperature would be hotter or colder, eliminating liquid water, an essential ingredient for our survival.

Oftentimes, if you're talking to a seasoned interviewer who asks you a question, they may do a follow-up if they didn't quite get it. It's rare that they'll do a third or fourth or fifth or sixth follow-up, because there's an implicit, agreed-upon decorum that they move on. Kids don't necessarily move on if they don't get it.

Black holes, we all know, are these regions where if an object falls in, it can't get out, but the puzzle that many struggled with over the decades is, what happens to the information that an object contains when it falls into a black hole. Is it simply lost?

All mathematics is is a language that is well tuned, finely honed, to describe patterns; be it patterns in a star, which has five points that are regularly arranged, be it patterns in numbers like 2, 4, 6, 8, 10 that follow very regular progression.

String theory envisions a multiverse in which our universe is one slice of bread in a big cosmic loaf. The other slices would be displaced from ours in some extra dimension of space.