Retrograde motion was important in the development of our understanding of the solar system because
A) it was not discovered until 1920.
B) it cannot be described with the geocentric model.
C) its description in terms of the heliocentric model is a great simplification in comparison to its description in terms of the geocentric model.
D) it happens only about once per century.

Question

Quizplus · Accepted Answer

Retrograde motion is more simply and accurately described by the heliocentric model (where planets orbit the Sun) than by the geocentric model (where everything orbits the Earth). This simplicity and accuracy were key in the development of our understanding of the solar system, supporting the transition from the geocentric to the heliocentric model.

Retrograde Motion Was Important in the Development of Our Understanding