DefinitionOne, several or all celestial spheres from the Ptolemaic geocentric model. The universe in classical, medieval, and Renaissance astronomy consists of nine concentric spheres revolving around the earth, each governing a celestial body or region. [English]
DefinitionOne, several or all celestial spheres from the Ptolemaic geocentric model. The universe in classical, medieval, and Renaissance astronomy consists of nine concentric spheres revolving around the earth, each governing a celestial body or region. [English]