Students study the ideas behind the heliocentric theory of Copernicus. They examine about retrograde motion of the planets as they move around the sun. They study astronomers who include Ptolemy, Copernicus, and Galileo.

Pupils trace the beginning of the heliocentric theory of the solar system--the idea that the solar system revolves around the Sun--to an observation by the Greek astronomer Aristarchus, which convinced him that the Sun was much bigger...

Students list differences in the diagrams of a geocentric universe and a heliocentric universe. They students describe the religious impact of this change on man's conception of the universe and man's place within it. Students describe...

Young scholars study the heliocentric theory of Copernicus, the ideas behind it and the explanations which it displaced. A discussion of retrograde motion of planets helps students explain the logic underlying the ideas of both Ptolemy...