Here's a proof that 2 planets orbiting each other will move on a planepic.twitter.com/kYqewE38Gw
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Actually for multiple objects it's really difficult (/ impossible) to express an exact solution in general relativity, hence to find the conserved quantities. For example energy is not conserved as the objects might generate gravitational waves.
For a planar symmetry like this, the thing which is conserved is the orientation of the angular momentum vector, but not necessarily its value.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.