A very tiny body is orbiting about a very heavy body. Both bodies are treated like point masses. In this simple case the orbit is represented by an ellipse which remains constant with respect to time. We call this ellipse Kepler Ellipse or Kepler Orbit.
Click into the applet's area and drag the mouse in order to change the shape of the ellipse. The bottom line shows the actual eccentricity.
Due to Kepler's third law the satellite is moving fast when near to the center body and slowly when far away from it. (A comet is spending most of its lifetime far away from the Sun).
Dieter Egger, last update 2002-02-26