What is the shape of our orbit? Aim: What are the Laws of
Planetary Motion? Topic: Unit 8 Astronomy Main Idea: Johannes
Kepler & Sir Isaac Newton What is Keplers 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 Parts of an
ellipse Keplers Second Law (Law of Equal Areas) A planet will sweep
equal amounts of area in equal amounts of time. What date are we
traveling the fastest in our orbit? Slowest? Keplers Third Law (Law
of Periods) Planets closer to the sun go around it faster because
there is more gravitational pull. Newtons Universal Law of
Gravitation Closer objects = bigger attraction Bigger objects =
bigger attraction Is there a relationship between distance to the
sun and eccentricity of orbit?
