Definition:Ptolemaic Astronomy

Definition

Ptolemaic astronomy was a model of the solar system in which:

$(1): \quad$ Earth is the center of the universe

$(2): \quad$ All the other celestial bodies orbit around Earth

$(3): \quad$ The orbits of those celestial bodies are epicycles.

Also see

• Definition:Heliocentric Model

• Results about Ptolemaic astronomy can be found here.

Source of Name

This entry was named for Claudius Ptolemy.

Historical Note

Claudius Ptolemy proposed this model of the solar system in his Almagest.

It modelled the actual behaviour of the planets to a high degree of accuracy.

However, when the heliocentric model of the solar system was proposed, it was realised that the latter model was considerably simpler.

When it was determined that the orbits of the planets were in fact elliptical, the resulting model was so much more simple and accurate, the Ptolemaic model was abandoned.