Doing a space walk. It is one of the most rare human experiences. To leave your spaceship and go outside, so that you are alone in the universe with Earth distant and the universe around you. That is amazing.

I'm not a wealthy person and I don't think that I would be able to prioritize that much money to go for a ride to a place that I have already lived. But if the price comes down or I win a lottery or something, why not?

"What's the next thing that's going to kill me?" is a mantra for pilots and astronauts.

The Nile, draining out into the Mediterranean. The bright lights of Cairo announce the opening of the north-flowing river’s delta, with Jerusalem’s answering high beams to the northeast. This 4,258 mile braid of human life, first navigated end-to-end in 2004, is visible in a single glance from space.

It's good to have a fear of heights. I mean, it's kind of crazy not to because if you just lean out a little bit and there's a gust of wind or somebody bumps you or something and you fall, you're splat.

Scientific literacy is one of the underpinnings of everything I do. It's why I work with schools. It's why I teach at university. I do a lot of outreach to try and improve general scientific literacy, but the core of all scientific literacy is just literacy.

There is no problem so bad that you cannot make it worse