AN ANCIENT QUESTION

In ancient times, people much more familiar with the night sky than we are helped themselves memorize its configurations by seeing heroes and creatures in clusters of stars. These constellations were patterns formed by stars fastened to a great sphere which surrounded the earth and formed the boundary of the universe. This celestial globe rotated on an axis through the earth, causing the stars to move along circular paths across the sky.

Likewise the life-giving sun was fixed to its own sphere whose rotation made the sun seem to travel across the sky each day, rising in the east and setting in the west. But unlike the stars, the sun gradually changed its path each day, rising and setting more northerly in the summer and more southerly in the winter.