title: Constant orbit using physics in Unity3D
body: <p>I am playing around with Unity3D and adding physics to the objects in my scene. I currently have a sphere (planet) in the center of the screen, and I have another sphere (moon) positioned outside of it that is not moving. When I run the game I want the moon to orbit the planet by applying a force to it. I have been able to get the force added by calling <code>rigidbody.AddForce()</code> and that will move it in the specified direction but it won't orbit. I'm not sure how to add force to it so that it will continuously orbit the sphere at a constant velocity. </p>
  
  <p>I've tried some examples using a <code>ConfigurableJoint</code> and it orbits, but it starts out bouncing a little and then starts the orbit. My goal is to have a bunch of orbiting moons orbiting at their own speed that are able to bounce off eachother but not lose their velocity.</p>
  
  <p>Any ideas?</p>