Pre-lab #4 The Celestial Globe

The Celestial Sphere

Celestial Sphere

Figure P.2 The Celestial Sphere Planet Earth sits fixed at the hub of the celestial sphere, which contains all the stars. This is one of the simplest possible models of the universe, but it doesn’t agree with the facts that astronomers now know about the cosmos.

Over the course of a night, the constellations appear to move across the sky from east to west. However, ancient sky-watchers noted that the relative positions of stars remained unchanged as this nightly march took place. It was natural for those first