crystal spheres

Crystal spheres refers to the ancient astronomical model in which celestial bodies were thought to be embedded in transparent, rotating spheres centered on Earth.

Each planet, the sun, moon, and stars occupied its own sphere, their movements producing the "music of the spheres." The model dominated Western cosmology from Aristotle through the Renaissance until replaced by Copernican heliocentrism.

The phrase now appears mainly in historical or poetic contexts: Galileo shattered the crystal spheres.