Ancient attempts to determine the scale of the cosmos

The science of astronomy developed in many different cultures and from many different motivations. Because, even in cities of the preindustrial world, the stars could be seen readily at night, the pageant of the sky was an inspiration for, and embodiment of, the myths and legends of almost all cultures. Some people tracked the fixed stars and moving planets with great precision, some for agricultural purposes (the ancient Egyptians needed to prepare for the annual flooding of the Nile River Valley) and more universally to attempt to predict the future. The regularity of the motions of the heavens was powerfully suggestive of the notion that history itself was cyclical, and hence predictable. The idea of human history linked to celestial events remains with us today as the practice of astrology. In spite of a lack of careful experimental tests, or demonstrated physical mechanisms, this powerfully attractive belief system is pursued widely with varying amounts of seriousness, extending in the early 1980s to the level of the presidency of the United States.

Although ancient understanding of the nature of the cosmos varied widely and was usually a reflection of particular mythologies of a given culture, the classical Greeks distinguished themselves by their (often successful) attempts to use experiment and deduction to learn about the universe. Some Greek philosophers understood the spherical nature of Earth and something of the scale of nearby space.