~~~snip~~~ Electromagnetic waves are far too slow to be the only means of signalling in an immense universe. Gravity requires the near-instantaneous character of the electric force to form stable systems like our solar system and spiral galaxies. Gravitationally, the Earth ‘sees’ the Sun where it is this instant, not where it was more than 8 minutes ago. Newton’s famous law of gravity does not refer to time. We must have a workable concept of the structure of matter that satisfies the observation that the inertial and gravitational masses of an object are equivalent. When we accelerate electrons or protons...