View Full Version : Perfect geometrically shaped orbits?

2019-Jun-24, 08:44 AM
Iiuc, for a 2-body system considering only gravity in Newtonian and GR frameworks (and ignoring the other forces, dark matter, dark energy), the orbit that most closely matches an ideal geometric shape (line, Euclidean curve, other?) is a photon orbiting a black hole. (For comparison, a system of 2 asymmetric extended bodies in an elliptical orbit precess and asymptotically circularize, and so are never either perfectly elliptical or circular.)

Are there any other 2-body systems where the orbit arguably matches an ideal geometric shape better than the photon-black hole setup?