Space is about 100 kilometers away. That’s far away—I wouldn’t want to climb a ladder to get there—but it isn’t that far away. If you’re in Sacramento, Seattle, Canberra, Kolkata, Hyderabad, Phnom Penh, Cairo, Beijing, central Japan, central Sri Lanka, or Portland, space is closer than the sea.

I've always thought that one of the the great thing about physics is that you can add more digits to any number and see what happens and nobody can stop you.

What people don't appreciate, when they picture Terminator-style automatons striding triumphantly across a mountain of human skulls, is how hard it is to keep your footing on something as unstable as a mountain of human skulls. Most humans probably couldn't manage it, and they've had a lifetime of practice at walking without falling over.

Take wrong turns. Talk to strangers. Open unmarked doors. And if you see a group of people in a field, go find out what they are doing. Do things without always knowing how they'll turn out. You're curious and smart and bored, and all you see is the choice between working hard and slacking off. There are so many adventures that you miss because you're waiting to think of a plan. To find them, look for tiny interesting choices. And remember that you are always making up the future as you go.

If at first you don't succeed, that's one data point.

A million people can call the mountains a fiction, yet it need not trouble you as you stand atop them.

The universe is probably littered with one-planet graves