title: What are some algorithms that will allow me to simulate planetary physics?
body: <p>I'm interested in doing a "Solar System" simulator that will allow me to simulate the rotational and gravitational forces of planets and stars.</p>
  
  <p>I'd like to be able to say, simulate our solar system, and simulate it across varying speeds (ie, watch Earth and other planets rotate around the sun across days, years, etc).  I'd like to be able to add planets and change planets mass, etc, to see how it would effect the system.</p>
  
  <p>Does anyone have any resources that would point me in the right direction for writing this sort of simulator?  </p>
  
  <p>Are there any existing physics engines which are designed for this purpose?</p>