(no subject)

http://www.colorado.edu/physics/2000/applets/satellites.html Orbit simulator, kind of interesting. The idea is to drag a rock off of the circling green object and try to get it to stay in orbit around the planet in the center. Of course, the object is subject to the gravitational fields of both the planet in the center and the circling green object. It should keep you occupied for at least a few minutes.