Kepler's+Laws

Kepler's three laws of planetary motion can be described as follows:

1. The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)

2. An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)

3. This is the most confusing, yet is used to determine the orbits of satellites and other objects, the wording is confusing, and for earth science, just know that there is a relationship between the distance from the sun and the length of the time it takes for a planet to travel around the sun.
 * The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)

(NOTE: The average distance value is given in astronomical units where 1 a.u. is equal to the distance from the earth to the sun - 1.4957 x 1011 m. The orbital period is given in units of earth-years where 1 earth year is the time required for the earth to orbit the sun - 3.156 x 107 seconds. )
 * ~ Planet ||~ Period(yr) ||~ Average Distance (au) ||~ T2/R3 (yr2/au3) ||
 * = Mercury ||= 0.241 ||= 0.39 ||= 0.98 ||
 * = Venus ||= .615 ||= 0.72 ||= 1.01 ||
 * = Earth ||= 1.00 ||= 1.00 ||= 1.00 ||
 * = Mars ||= 1.88 ||= 1.52 ||= 1.01 ||
 * = Jupiter ||= 11.8 ||= 5.20 ||= 0.99 ||
 * = Saturn ||= 29.5 ||= 9.54 ||= 1.00 ||
 * = Uranus ||= 84.0 ||= 19.18 ||= 1.00 ||
 * = Neptune ||= 165 ||= 30.06 ||= 1.00 ||

__**Regent's Questions**__