Soneca, there are a few links on the sidebar. My hope is that people will look for answers among the many excellent resources that are already available online. I also hope to develop the game further to make the physics that drives the planetary dynamics a little more clear.
For example, someone here commented about two stars systems, and if the planets are between them, they should closer to the center one as possible. This kind of thing I can test, see how it works and learn a little.
So a few tips as why another star in the center transform a planet's path from circular to an elliptic one, could help.