Three and a half million years ago our ancestors - yours and mine - left these traces [indicates footprints]. We stood up and parted ways from them. Once we were standing on two feet, our eyes were no longer fixated on the ground. Now, we were free to look up and wonder.

It turns out that the history of astrophysics is where we perfected time keeping.

We're talking about a being whose very existence challenges our own sense of priority in the universe.

Our entire universe emerged from a point smaller than a single atom. Space itself exploded in a cosmic fire, launching the expansion of the universe and giving birth to all the energy and all the matter we know today. I know that sounds crazy, but there’s strong observational evidence to support the Big Bang theory. And it includes the amount of helium in the cosmos and the glow of radio waves left over from the explosion.

A successful day for me is when I teach people something. They become enlightened by an idea and learn how to think about it, so that later on when someone says, "Tell me about x, y, z," they don't have to say, "I know this because Tyson told me." No, they'll say, "Here's why it's true because I know and understand it."

We live in a world where not everyone has the urge to help others... It is OK to encourage others to pull themselves up by the bootstraps, but if you do, just remember that some people have no boots.

If you're denying God's power, that means you don't really believe they were miracles, and so then why believe they happened at all. What you're saying is you're taking the Bible's account as literally true in need of a scientific explanation rather than just people coming up with stuff to fulfill their religious missions.