As important as the civil rights movement was, I think what will rise to the top is that we left Earth in that time.

I'm optimistic. I see no longer people accepting fuzzy thinking in the world. The change is not that people aren't still saying under-informed things. The change is that if you're in power and you say something under-informed, there are people out there with a voice who will take you to task for having done so

Life existed on Earth for nearly four billion years before anything remotely resembling a human being showed up. And even then, when we started to branch off from other apes about 10,000,000 years ago, our ancestors looked pretty different.

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.

My popularity does not derive from me pandering to people. People came to me. I don't tell anyone to follow me on Twitter. I don't tell people to like my Facebook page. I don't tell people to fill the venue. I'm offered to people, and then people come.

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.

I try to show the public that chemistry, biology, physics, astrophysics is life. It is not some separate subject that you have to be pulled into a corner to be taught about.