Eventually, the Sun will swell to occupy the entire sky as its expansion subsumes the orbit of earth. Earth's surface temperature will rise until it matches the 3,000-degree rarified outer layers of the expanded Sun.... But not to worry. We will surely go extinct for some other reason long before this scenario unfolds.

I would teach how science works as much as I would teach what science knows. I would assert (given that essentially, everyone will learn to read) that science literacy is the most important kind of literacy they can take into the 21st century. I would undervalue grades based on knowing things and find ways to reward curiosity. In the end, it's the people who are curious who change the world.

I can tell you about the universe, but she feels it; and when you feel the universe, it has a whole other meaning to you. Otherwise, you just put a Wiki page on camera. You can learn something, but it won't mean anything to you later on.

I try to write in a way where you care deeply what the next paragraph will be. I hear the rhythm of prose and that, to me, distinguishes great writing from ordinary writing. By the way, I don't even claim that I'm good. I claim that I value it.

On Venus you could cook a 16-inch pepperoni pizza in seven seconds, just by holding it out to the air. (Yes, I did the math.)

If NASA were advancing a space frontier there would be challenges you've never seen before. You have to be creative and you have to patent some new idea. You get to Mars...well, how do we get the water from the soil? I gotta invent a new device that will do that. And the carbon dioxide in the atmosphere, how can we use that? Can we breathe the oxygen from the carbon dioxide?

If you want a nation to have space exploration ambitions, you've got to send humans.