on his two epics describing war and the perils of trying to come home after long absence. For Homer, heaven is a solid inverted bowl straddling the earth, with fiery, gleaming "aither" above the cloud-bearing air. Homer mentions the movements of sun, moon, and many stars by name. The fact that Hades is on the underside of earth has an important impact on conceptions of heaven: it is unlit by the sun, therefore, the sun--and by extension, other heavenly bodies-- must sink only to the level of Ocean, which is conceived as a river circling earth's edge. From it the Sun must also rise--though how it gets back to the eastern bank of Ocean is never explained. These popular conceptions of sky are more fully explained in Hesiod, whose works on gods, on agriculture, and animal-herding are more closely connected to the practical application of astronomy. He clocks spring, summer, and harvest by solstices and the rising and setting of certain stars, and notices that the sun migrates southwards in winter As the Greeks began to travel and explore, their ideas of the order of the universe began to change. Many Greeks settled on the coast of Turkey in the early migrations of the eleventh century BCE, and there enjoyed rich cultural mingling with their neighbors the Lydians and Persians, latest descendents of Mesopotamian civilization. They kept in touch with their western cousins, who began a second wave of settling across the Aegean in the seventh century, as well as with other rich sea-faring cultures like Egypt. It is not surprising that, by the sixth century, these Ionian navigators of the sea began to develop new ideas about the sky they steered by. The most fundamental of these was that the universe might run, not only by the whim of gods, but by physical, mechanical rules and principles that might, through study, be understood and predicted. The sources for all early Greek astronomy are scant, none more so than for Thales, supposedly the first ...
