I Question about Mercury's orbit discrepancy

http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html

In the link given below, it is explained how general relativity predicts the correct results. However I am curious about the answer of the following hypothetical scenario. Let us assume that we replaced gravity with the electromagnetic force. Then the force of attraction would be the same, and mercury would be negatively charged and the sun positively charged. The question is, would the same discrepancy occur?

 

The way I see it is that the distortion of space-time is a result of generalizing SR into the geometry of spacetime. This means that Mercury experiences more "relativistic effects". So does not the electromagnetic force also cause relativistic effects? As far as I know you need a larger force to accelerate a faster moving object due to relativistic effects, and that would be the case for electromagnetism.

What is different about the relativistic effects in space-time and the relativistic effects of electromagnetism, which causes only space time to cause the discrepancy?

 

If charge increase as the sum of many point charges, it will also fall accelerate at the same rate.

If i recall correctly when I studied the derivation of E=mc^2 it seemed that it was based on assuming that mass is fundamentally a sum (integral).

So the fact that all objects has the same acceleration is in fact in itself not a proof of that space-time has to be curved. It could just be that all mass is a sum of different similarly quantized components.

 

I do know that. But that does not explain why the relativistic effects of electromagnetism would not cause the same discrepancy as gravity does. When generalizing SR into electromagnetism, should not that also predict something different than newtons laws?

 

I see, but that still does not explain why my hypothetical scenario would not predict the same discrepancy? Spacetime seems to say that when the force is larger, time is slower. If we consider a spaceship in high relative motion, electromagnetic interactions are also slower. Then when the electromagnetic force accelerates the hypothetically charged mercury, then time should be slower too? Then why do they not predict the same?

 

Similarly the hypothetical scenario of switching gravity with electromagnetic fields also predicts different motion. Because, when Mercury has a large momentary velocity, it accelerates slower. For the same reason why throwing a bottle (throwing bottle is electromagnetic interaction) in a rocket moving at the same speed would be slower too. This is something Newton's laws alone cannot explain. So why is it not the same difference from newtons law as GR predicts?

 

The electric field density should be stronger too corresponding to the strength in curvature of spacetime. Are there any experiments which proves that spacetime causes matter to behave differently than electromagnetic fields?