Strange as it may seem, wrote Richard Feynman, we understand the distribution of matter in the interior of the Sun far better than we understand the interior of the Earth.

Hardly anyone ever leaves. This is because Des Moines is the most powerful hypnotic known to man. Outside town there is a big sign that says, WELCOME TO DES MOINES. THIS IS WHAT DEATH IS LIKE. There isn't really. I just made that up. But the place does get a grip on you.

The remarkable position in which we find ourselves is that we don't actually know what we actually know.

You may not feel outstandingly robust, but if you are an average-sized adult you will contain within your modest frame no less than 7 X 10^18 joules of potential energy—enough to explode with the force of thirty very large hydrogen bombs, assuming you knew how to liberate it and really wished to make a point.

I can't think of anything that excites a greater sense of childlike wonder than to be in a country where you are ignorant of almost everything.

If you drive to, say, Shenandoah National Park, or the Great Smoky Mountains, you'll get some appreciation for the scale and beauty of the outdoors. When you walk into it, then you see it in a completely different way. You discover it in a much slower, more majestic sort of way.

There is the odd exception, like Albert Einstein, but as a breed, scientists tend not be very good at presenting themselves.