What are the basic pieces of astronomy knowledge that one should know coming out of high school? college?
Much as I love astronomy, my answer, sadly, is: Almost no minimum knowledge.
I wish it weren't so, but the plain fact of the matter is, no knowledge of astronomy is required to get along in social life, in practically any technical field, or in any other aspect of everyday life. The same cannot be said of mathematics, physics, English, history, biology, chemistry, etc, all of which are fields that are required in high school, and rightfully so. Astronomy gives one a sense of the grandeur of nature, but that borders on theology or philosophy, neither of which is required in high school, and rightfully so.
Some posters have brought up the Big Bang. This is obviously a seminal theory in cosmology, seeing as the main alternative has us floating in a sea of iron filings, but I think the odds of it being taught correctly, without major errors, is so fantastically low that we are probably better off if it isn't taught at all, or at least not required to be taught. Nothing is worse for science—in a rhetorical sense—than bad science.
If I were to require any knowledge in astronomy, it would be part of a general science course and would cover, probably, the fact that the planets orbit the sun, the moon orbits the earth, and the cause of the seasons. Actually apprehending that alone would suffice; very few people do. For example, why does summer begin with the summer solstice? Why isn't it centered around the solstice? At best, most people know only that the earth's tilt causes the seasons in some vague way.
The rest of that course would cover other sciences too fringe to be given a separate course. It would also discuss general science tools that no person—not no scientist, but no person—should be without, such as the meaning of probability and the significance of statistical data, the unreliability of anecdotal experience, the importance of controls, and so forth. We need these tools if we are not to be fooled by commercials, politics, and talk shows. These are very rarely taught in high school, their lack would not be the subject of ridicule at star parties, and yet they are incomparably more important than the relative sizes of the moon and earth.
Copyright (c) 2000 Brian Tung