1. What is the shape of our orbit?

2. Aim: What are the Laws of Planetary Motion? Topic: Unit 8 Astronomy Main Idea: Johannes Kepler & Sir Isaac Newton

4. What is Kepler’s First Law of Planetary Motion (Law of Orbits)? Planets travel around the sun in slightly flattened circles called ellipses.ellipses Eccentricity measures how flattened the circle is e=d/L 0=perfect circle; 1=straight line The sun is always at one focal point

5. Parts of an ellipse

6. Kepler’s Second Law (Law of Equal Areas) A planet will sweep equal amounts of area in equal amounts of time.

7. What date are we traveling the fastest in our orbit? Slowest?

8. Kepler’s Third Law (Law of Periods) Planets closer to the sun go around it faster because there is more gravitational pull.

10. Newton’s Universal Law of Gravitation Closer objects = bigger attraction Bigger objects = bigger attraction

11. Is there a relationship between distance to the sun and eccentricity of orbit?