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.

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.

I don't perceive an anti-religious agenda, especially with regard to Christians and Christianity.

I say to the grown-ups, 'If you want to deny evolution and live in your world that's completely inconsistent with everything we've observed in the universe that's fine. But don't make your kids do it.'

The most serious problem facing humankind is climate change.

As my old professor Carl Sagan said so often, 'When you’re in love, you want to tell the world.’ And I base my beliefs on the information and the process that we call science. It fills me with joy to make discoveries every day of things I’ve never seen before. It fills me with joy to know that we can pursue these answers. It is an astonishing thing that we are — you and I are one of the ways the universe knows itself.

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