Evolution is a theory, and it's a theory that you can test. We've tested evolution in many ways. You can't present good evidence that says evolution is not a fact.

I'll admit that the discovery of evolution is humbling, but it is also empowering. It transforms our relationship to the life around us. Instead of being outsiders watching the natural world go by, we are insiders. We are part of the process; we are the exquisite result of billions of years of natural research and development.

But as the cerebellum degrades with age, so does the quality of memories. The memories are there, but they're not as good.

The oncoming trouble I speak of is climate change. It's going to affect all of you in the same way the Second World War consumed people of my parent's generation.

My father was a very good Boy Scout. He was very skilled with knots, and he showed me how to tie a bow tie.

If you look back on all the teachers that you liked, I am sure you will find they were very entertaining.

Anybody who grew up with the space program is a fan of science fiction.