Astronomy is so easy to love. ... Fairly or not, physics is associated with nuclear bombs and nuclear waste, chemistry with pesticides, biology with Frankenfood and designer-gene superbabies. But astronomers are like responsible ecotourists, squinting at the scenery through high-quality optical devices, taking nothing but images that may be computer-enhanced for public distribution, leaving nothing but a few Land Rover footprints on faraway Martian soil, and OK, OK, maybe the Land Rover, too.

Science is not a body of facts. Science is a state of mind. It is a way of viewing the world, of facing reality square on but taking nothing on its face. It is about attacking a problem with the most manicured of claws and tearing it down into sensible, edible pieces.

evolution is a tinkerer, an ad-hocker, and a jury-rigger. It works with what it has on hand, not with what it has in mind. Some of its inventions prove elegant, while in others you can see the seams and dried glue.

Scientists have discovered that the small, brave act of cooperating with another person, of choosing trust over cynicism, generosity over selfishness, makes the brain light up with quiet joy.

Astronomers are pure of heart and appealingly puerile. They look into the midnight sky and ask big questions, just as we did when we were in college: Who are we? Where do we come from? And why are we standing around outside on the night before finals, do we want to end up making elevator parts for a living like our father or what?

Who needs a handgun when you've got a semiautomatic?

I may not believe in life after death, but what a gift it is to be alive now.