The fundamental difference between gravity and electricity is manifested in the everyday presence of all kinds of electromagnetic waves and in the total absence of gravitational waves. Gravitational interaction is apparently instantaneous, as reluctantly assumed by Newton and latter suggested by many researchers from Laplace to Eddington and Van Flandern. Indeed, from the astronomical evidence within the solar system, Laplace concluded that the speed of propagation of gravity has to be at least 108c. This limit has been pushed to 1010c in the last years by Van Flandern, thus strongly suggesting instantaneous propagation of gravity. To quote Van Flandern: "Anyone with a computer and an orbit computation or numerical integration software can verify the consequences of introducing a delay into gravitational interaction. The effect on computed orbits is usually disastrous because conservation of angular momentum is distroyed. Expressed less technically by Sir Arthur (Eddington), this means: ´If the Sun attracts Jupiter towards its present position S, and Jupiter attracts the Sun towards its present position J, the two forces are in the same line and balance. But if the Sun attracts Jupiter towards its previous position S´, and Jupiter attracts the Sun towards its previous position J´, when the force of attraction started out to cross the gulf, then the two forces give a couple. This couple will tend to increase the angular momentum of the system. And, acting cumulatively, will soon cause an appreciable change of period, disagreeing with observations if the speed is at all comparable with that of light.