This is a great image which show the problem with the dipole hypothesis.
The fields of both spheres disperse in the same rate.
That is because the area increases in the same rate with distance.
So with 2 equally but opposite charged spheres, independent of their sizes,
the electrical fields cancel each other out.
That is what I showed in the calculations.
Siggy_G wrote:.. charge isn't the same for both spheres
If you have different charges on or in the spheres, the total electrical field is
equal to the difference. Now we have a normal electrical field again,
not one that is dependent on mass, but on electric charge.
I think that you can argue that Mercury can be electrically charged,
as it receives a lot of charged solar wind.
And that this may give mercury an offset to its gravity only path, changing its orbit slightly.
Or maybe you want to use Sansbury's idea of smaller particles that carry the force of gravity in
some way. Or quasi-particles
. But this is not the same as charge (electron/proton).