When we see animals doing remarkable things, how do we know if we're simply seeing tricks or signs of real intelligence? Are talented animals just obeying commands, or do they have some kind of deeper understanding? One of the biggest challenges for animal researchers is to come up with tests that can distinguish between the two.

The last person I ever want working for me is someone who says 'that's not in my job description.

When I wrestled, I would set aside the time to wrestle, so that in my mind it didn't interfere with my study time. If I'd say, "I'm going to study this many hours, then I'm going to go work out and wrestle," then when that time comes, you don't feel like you should be doing something else. That helped me psychologically. But otherwise? When I'm wrestling, I'm not studying the universe. And when I'm studying the universe, I'm not wrestling.

Once upon a time, people identified the god Neptune as the source of storms at sea. Today we call these storms hurricanes.... The only people who still call hurricanes acts of God are the people who write insurance forms.

Trillions of years into the future, when all stars are gone...all parts of the cosmos will cool to the same temperature as the ever-cooling background. At that time, space travel will no longer provide refuge because even Hell will have frozen over. We may then declare that the universe has died-not with a bang, but with a whimper.

Imagination alone is not enough, because the reality of nature is far more wondrous than anything we can imagine

When NASA dreams big America dreams big. People...kids say, 'I want to do that when I grow up'. Because you want to do what's visible to you.