AS101 Lecture Notes - Lecture 10: Escape Velocity, Solar System, Inverse-Square Law
Document Summary
Based on uniform circular motion (objects move in circles at constant speeds) Explain retrograde motion of planets using epicycles (circles on circles. ) Kept the idea of uniform circular motion. Explains retrograde motion as the result of inner planets moving faster and overtaking the outer ones. Mercury and venus are inside the earth"s orbit, so they always appear close to the sun. Superior planets: the planets that orbit farther away from the sun, (from earth, the superior planets are mars, jupiter, saturn and uranus and neptune. ) Inferior planets: the planets that are closer to the sun, (from earth, these are mercury and venus. ) Superior planets can appear in the opposite direction from the sun, but inferior planets are always on the same side of the sky as the sun. Retrograde motion occurs when earth and a superior planet are on the same side of the sun. Using brahe"s observations, kepler developed a new, more accurate heliocentric model.
