It took a while to find relativity and the various subtle (or unmeasurable) effects it has within our universe. Is it possible that, although Newton's gravitational force equation leaves out any notion of density or size, this too might impact the forces acting around us?
I noticed this question already, but I am not satisfied with its answer. I wonder if two objects, A and B, having the same mass but (for lack of a better term) relativistically different densities, would exert slightly different gravitational forces on a third object C which is far enough from A and B (and equally distant from both) to negate any "diffusion" effects on the gravitational fields of A and B?
In other words, is it possible that the equations we have are "good enough", and we just don't have examples (yet) that introduce the same kind of errors as those that confirmed the theory of relativity?
If not, why not? Is there any particular reason aside from "these are the equations we have"?
I realize that finding the mass of something like a black hole would be at best impractical, if not entirely impossible, without assuming that its mass directly determines its gravitational field strength.