Unformatted text preview: culmination with the model of Ptolemy. The Ptolemaic model explained apparent retrograde motion by having each planet move on a small circle whose center moves around earth on a larger circle. What are Kepler's Three Law's of Planetary Motions? 1. The orbit of each planet is an ellipse with the sun at one focus 2. As a planet moves around its orbit, it sweeps out equal areas in equal times 3.More distant planets orbit the sun at slower average speeds, obeying the precise mathematical relationship p^2=a^3...
View Full Document
- Spring '10
- Astronomy, Planet, Kepler's laws of planetary motion, Copernicus