Casual Comments On Newton's Gravity

Rightly or wrongly Isaac Newton gets credit for the inverse-square law of universal gravity. Mathematically it is an instantaneous-action-at-a-distance formulation. I read that Pierre-Simon Laplace investigated modifying the formulation to incorporate propagation delay. What he found was that unless the propagation speed was millions of times faster than the speed of light, the solar system would go unstable in a matter of centuries. In 1900 Hendrik Lorentz published a paper wherein he attempted to show that a theory of gravity was possible with a more reasonable propagation speed and at the same time a stable solar system. He borrowed an idea from Ottaviano-Fabrizio Mossotti, i.e., that gravity is nothing more than an imbalance in electric forces. Without going into detail here Lorentz showed that his version of an electromagnetic formulation of gravity with propagation of fields/forces at the speed of light had no first-order correction terms and thus yielded a stable solar system. There is an objection that such "vector theories" of gravity are untenable because of something called Maxwell's negative energy difficulty. We'll come back to this subject again, because I claim that James Clerk Maxwell made an error when he looked for a link between electromagnetism and gravity.