On Apr 10, 2011, at 8:26 PM, This email address is being protected from spambots. You need JavaScript enabled to view it. wrote:

What happens if you add Wheeler-Feynman advanced effects? - another line of inquiry.

An interesting line of enquiry. The key difficulty is how to solve the resulting equations. I have been trying to solve such equations in the case of electrodynamics ("Simulating a tilt in the arrow of time", 1995 unpublished conference paper), and I did suggest a technique some years ago, but did not follow it up, though I intend to do so shortly. Hence, the retardation is explicit in the title.

CK

On Apr 10, 2011, at 8:20 PM, This email address is being protected from spambots. You need JavaScript enabled to view it. wrote:

Dear Jack,

Thanks for your questions.


Are you sure that Einstein's GR in the post-Newtonian approximation
does not already contain the new terms you use?

No, I am not sure since I did not do the calculations myself, but the published claim is that the GR frame drag cannot account for the flyby anomaly.

There would be further difficulties. If oblateness is important, one cannot use the Kerr solution. One could patch an external Kerr-like solution to an oblate object using my method ("Junction Conditions in General Relativity", J. Phys. A: 15 (1982) 1785-97, or its generalisation arXiv:0804.1991), but it seems  complicated.  


There is no clear-cut statistical way of going from a system of particles to a density in GRT, as there is in classical thermodynamics. Though the galaxy  seems a collection of discrete stars a typical relativist would model it using a "fluid". However, the  observed mass distribution can be related to the theoretically assumed one only "intuitively". Moreover, as far as I know, no one has actually managed to account for galactic rotation curves in this way.

Accordingly, I have not yet taken a position on whether or not GRT can account for the effects that are a clear consequence of RGT.

Clearly, RGT is so much *easier* for many-body problems.

Since Lorentz covariance is absolutely essential to [present-day] physics, it seems to me more important to first settle *experimentally* the question of (a) RGT vs Newtonian gravitation, before tackling the question of (b) RGT vs GRT.



CKR