text: The elliptical orbits are the result of Kepler's Law; the shape of a planet's orbit around a larger mass is a function of each planet's mass and the distance between the orbits.  One can derive the elliptical orbit path from Newton's Laws; when you start from Newton's Laws and perform this derivation, your result will be an equation in the form of an ellipse.\n\nSometimes orbits are not elliptical, but are circular.  Consider binary stars - when the masses of 2 binary stars is equal, the respective orbial path traced by each star is a cicrle in the complex plane, not an ellipse.\n\nBy the way, symmetry is one of the most natural phenomena observable.  To say that symmetry is not found in nature very often is an indication of lack of advanced physical and mathematical study.  Consider rings, field, and group theory.  Symmetric wavefunctions of identical particles and allowable energetic transition states in a molecule or, in some cases, an atom.  I could list 1000 different natural PERFECT symmetries based on solid foundations of laws of conservation and irrefutable mathematics, but only because I am limited as a human being in my knowledge of symmetrical processes.  There are many more than 1000 examples.  You get my point.