Science Porn

[Jehanne]

Jehanne,

Yes you're right. The Lagrange points are a prediction of the newtonian laws of motion, and if you throw that away and go to a geocentric picture, to explain observations all those epicyclic convoluted laws of planetary motion need to be postulated ad hoc without  a sound theoretical base. One could of course simply postulate the lagrange points as well ( because if you don't have a unifying theoretical framework, anything goes) but there is no theoretical *reason* for them to be there, no prediction, because the geocentric model has little predictive power beyond what is put in explicitely.

Predictions, bah.  Lagrange points would simply require a few more of those geocentrically rotating transparent celestial spheres that had already been postulated for planets and the sun to be embedded in.  

I don't think that such a mathematical model exists, period, no matter how many epicycles are thrown in.  Forgot about the inverse square law, Newtonian mechanics, and all the rest.  Observationally speaking, one could observe the rotation of the Earth at the Lagrange points, and a geocentric model of the solar system could not simply account for those observations, even assuming an Earth-centered view of things.