When we see the shadow on our images, are we seeing the time 11 minutes ago on Mars? Or are we seeing the time on Mars as observed from Earth now? It's like time travel problems in science fiction. When is now; when was then?

There really is no such thing as race.

Apparently there is redundancy in memory: You store the same memory in different parts of your brain for accessing at different speeds. That speed would depend on the frequency of use and the importance of the knowledge.

I tell personal stories associated with aspects of the theory, and I hope they are interesting and compelling. I don't feel you're going to change a grownup's mind in one reading. People have to be exposed to scientific ideas over and over again for years. It's also not a textbook.

There's nothing I believe in more strongly than getting young people interested in science and engineering, for a better tomorrow, for all humankind.

There really is no such thing as race. We all came from Africa. We are all of the same stardust. We are all going to live and die on the same planet, a Pale Blue Dot in the vastness of space. We have to work together.

I abandoned my religious teachings after I read the Bible twice - cover to cover. It took me a couple of years.