KeplerSystem


General Description

This simulations illustrates Kepler's final theory of planetary motion. In this theory the planets orbit in ellipses with Sun at one focus (Kepler's First Law). These elliptical orbits are not necessarily all in the same plane. A line from Sun to the planet sweeps out equal areas in equal times (Kepler's Second Law). The square a planet's period is directly proportional to the cube of the semimajor axis of its elliptical orbit (Kepler's Third Law).

The simulation shows Earth's orbit around Sun, as well as the orbit of one other planet. The user can choose to show one of the five visible planets (Mercury, Venus, Mars, Jupiter, or Saturn), or a fictitious planet. The top window shows the orbits of the planets around Sun. The view can be changed by clicking and dragging in the window, and a zoom slider is provided to zoom in or out. The bottom window shows the view of Sun and planet against the background stars as seen from Earth.


Orbit Frame


Ecliptic View Frame


Orbital Parameters

This panel appears if the user selects a user-defined planet.

Orbital Data for Visible Planets

All data is taken from the National Space Science Data Center's fact sheets found at http://nssdc.gsfc.nasa.gov/planetary/.
Planet Semimajor Axis Eccentricity Inclination Longitude of Ascending Node Argument of Perihelion*
Mercury 0.3871 AU 0.2056 7.0049 deg 48.3317 deg 29.1248 deg
Venus 0.7233 AU 0.0068 3.3947 deg 76.6807 deg 54.8523 deg
Earth 1 AU 0.0167 0 NA 102.9472 deg*
Mars 1.5237 AU 0.0934 1.8506 deg 49.5785 deg 286.4623 deg
Jupiter 5.2034 AU 0.0484 1.3053 deg 100.5562 deg 274.1977 deg
Saturn 9.5371 AU 0.0542 2.4845 deg 113.7150 deg 338.7169 deg
*The Argument of Perihelion value for Earth is actually the ecliptic longitude of Earth's perihelion.
Todd K. Timberlake (ttimberlake@berry.edu)