ASTR 101 Chapter Notes -Non-Inclined Orbit, Deferent And Epicycle
1 Feb 2014
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Kepler and his three laws: kepler wanted to make sense of brahe"s data by making a radical assumption (against. Brahe"s last wish) that copernicus"s heliocentric model was a good basis to start with. Assumed the heliocentric model and that earth"s orbit around the sun was nearly circular. A very bold/dangerous assumption, however it is correct. If earth"s orbit was not near circular, there would be extremely variable climate that humans could not withstand. Assuming a circular orbit also allow kepler to work out the clearly elliptical orbits of the other planets: to map the orbit of other planets, kepler used brahe"s database of planetary data. Mars orbits the sun once every 687 days, or 1. 88 years, meaning that once every. 687 days mars will have made a complete orbit, yet appears in a different location than observed 687 days ago.
