What are the origins of the Geocentric and Heliocentric models

put foward to explain planetary motion? This lecture begins a new

unit that will chart the rise of our modern view of the solar system by

reviewing the highly influential work by Greek and Roman philosophers

who elaborated the first geocentric and heliocentric models of

the Solar System. We discuss the various geocentric systems from

the simple crystaline spheres of Anaximander, Eudoxus, and Aristotle

through the Epicyclic systems of Hipparchus and Ptolemy. We will

also briefly discuss what is known of Aristarchus' mostly-lost heliocentric

system, which was to so strongly influence the work of Copernicus. The

ultimate expression of an epicyclic Geocentric system was that

described by Claudius Ptolemy in the middle of the 2nd Century AD, and

was to prevail virtually unchallenged for nearly 14 centuries.

Recorded 2006 Oct 9 in 100 Stillman Hall on the Columbus campus

of The Ohio State University.