During the 1970s and 1980s, the popular television soap opera As The World Turns portrayed sunrise during the opening credits and sunset during the closing credits... The soap-opera sunrise showed the sun moving toward the left as it rose rather than to the right. They obviously had gotten a piece of film showing a sunset and played it in reverse... Had they called their local astrophysicists, any one of us might have recommended that if they needed to save money, they could have shown the sunset in a mirror before they showed it running backward.

Once you've got the makings of a star, gravity draws leftover gas and dust into a giant swirling disk. The dust continues to stick together, clumping into rocky asteroids, which eventually become orbiting rocky planets. And voila: a solar system!

I try to write in a way where you care deeply what the next paragraph will be. I hear the rhythm of prose and that, to me, distinguishes great writing from ordinary writing. By the way, I don't even claim that I'm good. I claim that I value it.

There are no wild, seedless watermelons. There's no wild cows... You list all the fruit, and all the vegetables, and ask yourself, is there a wild counterpart to this? If there is, it's not as large, it's not as sweet, it's not as juicy, and it has way more seeds in it. We have systematically genetically modified all the foods, the vegetables and animals that we have eaten ever since we cultivated them. It's called artificial selection.

Knowing how to think empowers you far beyond those who know only what to think.

There was a transition going on - Baghdad being the intellectual capital of the world where major advances were made in agriculture and mathematics and engineering and medicine and astronomy, and then that all sort of collapsed. And I was trying to understand how such a intellectually fertile environment can lose its compass bearing. Because I think about the creative centers today - countries, or even regions. Will Silicon Valley always be as innovative? Will the United States be innovative, or will we become complacent?

The more I learn about the universe, the less convinced I am that there's any sort of benevolent force that has anything to do with it, at all.