As several previous speakers have noted, astronomers are a rare breed. Even though we represent the oldest science, we are as rare as poets. The fact that our discipline is so distinct suggests that it should also have its peculiar pedagogical problems. I have been attempting to understand a pervasive element of all astronomical thinking — the use of spatial imagination to link celestial phenomena to terrestrial analogs. My work has two components — a theoretical explication of astronomical thinking and some practical use of these ideas in teaching situations.

If one looks at some of the fundamental “facts” discovered by astronomers, we will find that we often do not, in fact, directly verify our discoveries as scientists supposedly do. Primary astronomical “truths” such as the sphericity of the Earth, the heliocentric orbit of the Earth, the identification of the stars as distant suns, and the recognition that galaxies are enormous collections of stars, were not discovered by direct verification. Thus, we note that the Greeks discovered the Earth’s sphericity nearly two millennia before its circumnavigation and that only a few thousand very bright stars in nearby galaxies have been resolved in our largest telescopes. Some of the primary objects of astronomical discourse, then, are not perceptible objects, but objects created by the spatial imagination.