To leave the world better than you found it, sometimes you have to pick up other people's trash.

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.

Everybody remembers numbers and computers remember numbers. People remember procedures and computers certainly remember procedures. But the other thing that's still important is that your perception as a human is affected subtly by all this stuff that you can't quite articulate. You run your life according to all this stuff that's happened to you. All of your memories affect everything you do whereas with a computer, there's adaptive software and things, but it's more literal.

When we explore the cosmos, we come to believe and prove that we can solve problems that have never been solved. It brings out the best in us. Space exploration imbues everyone with an optimistic view of the future.

The most serious problem facing humankind is climate change.

The information you get from social media is not a substitute for academic discipline at all.

But investment in space stimulates society, it stimulates it economically, it stimulates it intellectually, and it gives us all passion.