This is a rough simulator to show how "Planet 9" could be detected without ever being visually observed. Use the slider scale to vary the mass of Planet 9. Click the Sun to show or hide Planet 9. Click the background to clear and re-start the traced paths of the comet and Planet 9.
Note the stable orbit of the comet if the mass of Planet 9 is set to 0. Check to see how different masses affect the orbit. Try hiding Planet 9 and trying to predict where it is located based only on the behavior of the comet.
