Agreed with this, there are various ideas in the literature whch are used to try to explain why solar system orbits appear to be two dimensional with respect to the sun. Most of them use evolutionary arguments. However, the sun is itself orbiting the centre of the Milky Way, so the overall orbits of the planets are three dimensional as you infer. It seems that the Milky Way (a spiral galaxy) is also orbiting another galaxy. The orbit of the moon about the earth is nearly circular, and tilted at 5 degrees to the earth’s orbit about the sun. So the moon’s orbit about the sun is not planar as you infer.
Sent: 02/02/2017 12:18:38 GMT Standard Time
Subj: Re: 369(7): Complete Solution for Spherical Orbits in a Central Force Field
In fact, orbits must be three dimensional – and the flat world properly ended!
Sent from my Samsung device