When I wrestled, I would set aside the time to wrestle, so that in my mind it didn't interfere with my study time. If I'd say, "I'm going to study this many hours, then I'm going to go work out and wrestle," then when that time comes, you don't feel like you should be doing something else. That helped me psychologically. But otherwise? When I'm wrestling, I'm not studying the universe. And when I'm studying the universe, I'm not wrestling.

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

You can't be a writer and have nothing to write about. You have to have life experiences.

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 molecules that comprise our body are traceable to the crucibles of the centers of stars.These atoms and molecules are in us because, in fact, the universe is in us. And, we are not only figuratively, but literally, stardust.

All tweets are tasty. Any tweet anybody writes is tasty. So, I try to have each tweet not simply be informative, but have some outlook, some perspective that you might not otherwise had.

While the Copernican principle comes with no guarantees that it will forever guide us to cosmic truths, it's worked quite well so far: not only is Earth not in the center of the solar system, but the solar system is not in the center of the Milky Way galaxy, the Milky Way galaxy is not in the center of the universe, and it may come to pass that our universe is just one of many that comprise a multiverse. And in case you're one of those people who thinks that the edge may be a special place, we are not at the edge of anything either.