Whatever I was going into, whether it was going to be chorus or history or astronomy or whatever, do it right. Be a professional. Don't just do a half baked job. Do everything correctly. Get down. Learn the details of what you're going to do.

What we're learning is that the sun and its warmth isn't the only way to get warmth in the solar system, and we've been thinking that for some time.

We need people pushing the boundaries. Exploration is what we, as humans, do.

Because exploration is not science driven, you've got to ask what is it driven by? And it's driven by politics.

The simple facts of Chadian life - what it takes to survive in that kind of climate with nothing but a hut and some animals - stunned me. And this made me realize, perhaps for the first time, how easy my life was compared to those of people in less privileged societies.

After spending three or four years interacting with the Bush administration, I realized they were not taking any actions to deal with climate change. So, I decided to give one talk, and then it snowballed into another talk and eventually to even protesting and getting arrested.

As President Trump quickly moved to limit immigration, civil rights, and environmental protections, I felt fear for my young children, and guilt, too - as if I'd somehow betrayed the unspoken contract all parents make to give our children a better life than ourselves.

I'd like to avoid the environmental apocalypse if I could. Zombies, robots - I don't know - I'd probably do alright hidden in the middle of the herd and sacrificing people to keep myself alive, but where you gonna hide when all the food is gone?