Eratosthenes's only tools were sticks, eyes, feet, and brains; plus a zest for experiment. With those tools he correctly deduced the circumference of the Earth, to high precision, with an error of only a few percent. That's pretty good figuring for 2200 years ago.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.

I promise to question everything my leaders tell me. I promise to use my critical faculties. I promise to develop my independence of thought. I promise to educate myself so I can make my own judgments.

If we offer too much silent assent about mysticism and superstition - even when it seems to be doing a little good - we abet a general climate in which scepticism is considered impolite, science tiresome, and rigorous thinking somehow stuffy and inappropriate.

For years I've been stressing with regard to UFOs that extraordinary claims require extraordinary evidence.

We live in an in-between universe where things change all right...but according to patterns, rules, or as we call them, laws of nature.

The universe is a pretty big place. If it's just us, seems like an awful waste of space.