We went to the moon using just Newton's laws of motion and gravity. Newtonian dynamics we call it. So then we find out, "Well, this works because there's certain regimes we've never tested it in." Had we done so, we would show that it didn't work: For example, at very high speeds, very high gravity, Newton's laws fail. They just fail. You need Einstein's laws of motion and gravity. Those would be his special theory of relativity and general theory of relativity. Now you invoke those and it works.

When provoked, the itsy-bitsy invertebrates known as tardigrades can suspend their metabolism. In that state, they can survive temperatures of... 73 K for days on end, making them hardy enough to endure being stranded on Neptune. So the next time you need space travelers with the right stuff, you might want to choose yeast and tardigrades, and leave your astronauts, cosmonauts, and taikonauts at home.

Grab something off the shelf that's on the spaceship-an ashtray, it doesn't matter what. Because I can tell you, if they flew here from another galaxy, no matter what you've pulled off the shelf, it'll be unlike anything we have on Earth.

While I'm a big fan of science fiction, especially as rendered in expensive Hollywood blockbusters, it's the real universe that calls to me. To fall into a black hole, that is more amazing than anything I've ever read in a science-fiction story.

What are you doing? Why are you concerning yourself with the meaning of meaning?

Some claim evolution is just a theory. As if it were merely an opinion. The theory of evolution, like the theory of gravity, is a scientific fact. Evolution really happened. Accepting our kinship with all life on Earth is not only solid science. In my view, it’s also a soaring spiritual experience.

If God to you is where science has yet to tread, then God is an ever-receding pocket.