If you get asteroids about a kilometer in size, those are large enough and carry enough energy into our system to disrupt transportation, communication, the food chains, and that can be a really bad day on Earth.

They [scientists of centuries past] call on God only from the lonely and precarious edge of incomprehension. Where they feel certain about their explanations, however, God gets hardly a mention.

You could be a poet, an artist, a comedian - if you're in the culture of innovation then you embrace those who do and you're going to protect the science curriculum in the classroom because you understand the meaning and the value of it. And science discoveries don't scare you. You say, "Give me more science", not less. "Give me more technology", not less.

On Venus you could cook a 16-inch pepperoni pizza in seven seconds, just by holding it out to the air. (Yes, I did the math.)

And extracting one molecule's signature in spectral analysis from the rest of the signatures is hard work, sort of like picking out the sound of your toddler's voice in a roomful of screaming children during playtime. It's hard, but you can do it.

When you're advancing a frontier it stimulates creativity to find solutions.

If we have the power to turn another planet into Earth, then we have the power to turn Earth back into Earth.