The FAQs are the collective efforts of Usenet group participants who, after a wave of questions on a topic, "would make a very intelligent post trying to end the conversation once and for all," says Scott Chase, a semiconductor researcher at Clear Logic in San Jose, California, who maintains the physics FAQ. The resulting documents, many of which have now migrated to the Web, span the practical to the profound: The physics and relativity FAQs, for example, cover the purpose of golf ball dimples, tachyons (hypothetical particles that travel faster than light), and whether energy is conserved in the universe, with authors including top experts like John Bahcall of the Institute for Advanced Study in New Jersey. At the astronomy FAQ (linked to physics), you can learn why you sometimes see a flash of green at sunset, or download a glossary of space acronyms. And this chemistry FAQ site details everything from finding patents on the Net to the meaning of "omega-2 fatty acids" and how to make chemical lightsticks.

Chase warns of "phony" science FAQs from "wackos peddling their personal opinion." One place to find the real thing is this site that mirrors an MIT archive of FAQs. They run the gamut from the ozone layer to dodo extinctions and www.talkorigins.org, which debunks creationist arguments.