The Earth is just one place of many that we could hang our hats.

When students cheat on exams, it's because our school system values grades more than students value learning.

Those who see the cosmic perspective as a depressing outlook, they really need to reassess how they think about the world. Because when I look up in the universe, I know I'm small but I'm also big. I'm big because I'm connected to the universe and the universe is connected to me.

Anyone who has wrestled knows that it's the hardest thing in the world to do. Anyone who says something else is the hardest thing has never wrestled. That's what I have found. ... You don't wrestle because it's easy, you wrestle because it's hard. I don't do astrophysics because it's easy, I do it because it's hard. And I juxtapose the two in my mind, body, and soul all the time.

We still don't know for sure what the trigger was, but since we've discovered meteorites with supernova dust, we do know that a violent explosion rocked our cosmic neighborhood at the time of our birth, and it's quite possible that without it, our stable, stately solar system would never exist at all.

Science is basically an inoculation against charlatans.

I think that intelligence is such a narrow branch of the tree of life - this branch of primates we call humans. No other animal, by our definition, can be considered intelligent. So intelligence can't be all that important for survival, because there are so many animals that don't have what we call intelligence, and they're surviving just fine.