Have you ever seen a demonstration of any of the principles of General Relativity? What about The "famous" "rubber sheet" analogy, where a heavy ball, like a bowling ball, is placed on a rubber sheet? Of course, the rubber sheet is stretched as the heavy ball "weighs down" on it, creating a large indentation, like a funnel shape. This is almost invariably followed by placing a small, far lighter ball on the sheet, with enough transverse velocity that it "orbits" the larger, heavier ball.
Well, who would have guessed that the rubber sheet demonstration does not reproduce the correct, General Relativistic phenomena? Yes. Check out the article at Famous Spacetime Analogy Wrong - [RealClearScience].
Perhaps the real question is whether the rubber sheet demonstration is useful, in any way, for helping people understand, or even just appreciate General Relativity? After all, it is an analogy, after all, and don't all analogies "break down" at some point?
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While I think the rubber sheet demonstration does have some utility, at least in helping the general public have some inching of what General Relativity (GR) does, I think it has far greater problems than simply not reproducing the motions predicted by GR, let alone Kepler's Laws.
