Successes and problems of the geocentric model
Successes:
- Explains phases of the moon
- Does a good job of predicting positions of sun and moon
- Does an OK job of predicting the positions of Mars, Jupiter & Saturn
Problems:
- Didn’t explain retrograde motion. Why would perfect circular motion reverse itself?
- Didn’t explain why Mercury and Venus stay close to the Sun.
- Didn’t explain why planets are brighter when they are opposite the sun in the sky.
- Keeps earth in the proper “fallen” place.