PHY 102 Lecture Notes - Lecture 3: Semi-Major And Semi-Minor Axes, Orbital Period, Tychonic System
Document Summary
Observing something through a different angle because you moved. If the earth moves you should see the stars move against the background. Stars are too far away to show parallax to naked eye. Wanted naming rights to the solar system. Biblical passages hard to reconcile with moving earth. Tycho hired kepler to work on his model. Kepler made a model off tchyo"s observations. The orbits of the planets are ellipses with the sun at the center. Line connecting the sun and a planet will sweep out equal areas in equal times. Square of orbital period of a planet is proportional to the cube of the semimajor axis. Years and astronomical units k = 1. Seconds and meters k = 2. 97 x 10^-19 s^2/m^3. Planet not always same distance from sin. Planet moves at different speeds at different parts of its orbit. Planets with bigger orbits move slower and have longer periods.
