What were the small circles, championed by Ptolemy, upon which planets moved while their centers traversed larger paths?
Answer
Epicycles
To account for retrograde motion while keeping Earth central, ancient astronomers moved planets along small circles called epicycles, whose centers moved along larger circles called deferents.
Related Questions
What is the geocentric model often called, named after an influential Greek astronomer?What was the most immediate and compelling strength of the geocentric view?What specific, erratic planetary behavior forced the geocentric model to adopt complex additions like epicycles?What were the small circles, championed by Ptolemy, upon which planets moved while their centers traversed larger paths?Which key observation, later confirmed by Galileo with his telescope, provided powerful evidence against the geocentric structure?The inability to detect which phenomenon led proponents of the geocentric model to logically conclude that the Earth must not be moving?What factor allowed the geocentric model to dominate for over a thousand years despite its mathematical complexities?Philosophically, why was placing humanity at the center of the cosmos appealing to many historical thinkers?In contrast to the geocentric view, what does the heliocentric model explain retrograde motion as?What key scientific virtue did the geocentric model ultimately sacrifice in order to match observational data accurately?