Sphere of the Fixed Stars

The Sphere of the Fixed Stars is an ancient astronomical concept imagining the universe as a series of concentric, transparent spheres. The stars are affixed to the outermost sphere, which rotates daily around Earth, creating the impression of the stars moving across the night sky. Unlike planets, which have complex orbits and varying positions, fixed stars appear unchanged, maintaining relative positions. This model was used in historical astronomy to explain celestial motions before the heliocentric model. Today, we understand stars are at vast, varied distances, but the term persists in describing the apparent, consistent positions of distant stars viewed from Earth.