There is an interesting cartoon that shows two small boys and a dog. In the first panel, one boy says to the other “I taught Stripe (the dog) how to whistle!” In the second panel, the other boy replies “I don't hear him whistling!” In the third and final panel, the first boy says “I said I taught him; I didn't say he learned it”.

This cartoon emphasizes the difference between teaching and learning. Research shows that, in the most traditional methods of teaching, the amount of learning may be zero. Of course, there is more to teaching than the learning of facts. In fact, there is an old saying that “education is that which remains after the facts have been forgotten.” So it can include the intangible effects of an inspirational teacher.

There are many important challenges in the effective teaching and learning of astronomy, and most of them are amenable to research. One challenge is students' deeply rooted misconceptions about astronomical topics; non-expert teachers often share the same misconceptions. Some of these misconceptions are caused by the influence of religion or of popular culture. Others result from the three-dimensional nature of many astronomical concepts, or from the problems of moving from an observer-centered frame of reference to an external one, or from the enormous astronomical scales of size, distance, and time. Many of these concepts are intrinsically difficult, and the work of Piaget and others seemed to show that these concepts require students to have reached the appropriate stage of intellectual development - secondary school, for instance.