Ptolemaic system(redirected from Geocentric System)
Also found in: Thesaurus, Encyclopedia.
Related to Geocentric System: Heliocentric System
The astronomical system of Ptolemy, in which the earth is at the center of the universe with the sun, moon, planets, and stars revolving about it in circular orbits at increasing distance. Some of the orbits have epicycles.
(Astronomy) the theory of planetary motion developed by Ptolemy from the hypotheses of earlier philosophers, stating that the earth lay at the centre of the universe with the sun, the moon, and the known planets revolving around it in complicated orbits. Beyond the largest of these orbits lay a sphere of fixed stars. See also epicycle1 Compare Copernican system
Ptolemy's conception of the universe, with the earth as the fixed center and the heavenly bodies moving about it.
Ptolemy believed that Earth was at the center of the universe and that the sun and planets orbited Earth (with the planets also moving in smaller circles called epicycles). In this system, the centers of Mercury's and Venus's epicycles always lie on the line shown in the diagram between Earth and the sun.
The astronomical system of Ptolemy, in which Earth is at the center of the universe and all celestial bodies revolve around it. The sun, moon, and planets revolve at different levels in circular orbits, and the stars lie in fixed locations on a sphere that revolves beyond these orbits.
Switch to new thesaurus
|Noun||1.||Ptolemaic system - (astronomy) Ptolemy's model of the universe with the Earth at the center|
framework, model, theoretical account - a hypothetical description of a complex entity or process; "the computer program was based on a model of the circulatory and respiratory systems"