The solar system should be viewed as our backyard, not as some sequence of destinations that we do one at a time.

Ignorance is a virus. Once it starts spreading it can only be cured by reason. For the sake of humanity, we must be that cure.

Don't get in the way of children who find it natural and obvious to explore the world around them - even if it means they make a mess of your kitchen or living room. It's all about your perspective on these things. Let them play. When you do, the kids do not have to be reintroduced to ways of questioning nature, and the task of promoting science would be a trivial exercise.

Because we all just function, the rest of us, just go to work and come home; artists make life bearable. They give perspectives on things we never knew you could have. They bring joy. They explore inner human emotion, and at its best, the full dynamic range of that emotion.

A common way to compute density is, of course, to take the ratio of an object's mass to its volume. But other types of densities exist, such as the resistance of somebody's brain to the imparting of common sense.

When I needed to overcome the low expectations of others or the bias that would be expressed in one circumstance or another, I'd keep on keeping on. And I climb over the obstacle, go around it, dig under it, fly over it. That's what kept me going. Otherwise I would have never been an astrophysicist.

If your ego starts out, "I am important, I am big, I am special," you're in for some disappointments when you look around at what we've discovered about the universe. No, you're not big. No, you're not. You're small in time and in space. And you have this frail vessel called the human body that's limited on Earth.