# Classical gravitational wave

Consider the electric field surrounding an electron. The electron moves. A wave propagates at $c$ reflecting the electron's movement. This is an electromagnetic wave. Consider a mass. Classically surrounded by a gravitational field. The mass moves. The field deforms and it propagates at $c$.

• Is this not a gravitational wave?

• Why do people talk as if only general relativity predicted gravitational waves?

• Compare Maxwell's equations for electromagnetism (with time derivatives of the fields) and Poisson equation for gravity (with no time derivatives). – AccidentalFourierTransform Jan 18 '16 at 6:40
• The catch is that classical gravity works instantaneously, not at c. This would still produce a "wave" with infinite velocity and infinite wavelength, if you would see it that way. – busukxuan Jan 18 '16 at 6:53

Newtonian gravity doesn't predict anything traveling at speed $c$ as neither the constant $c$ nor any constants you can use to make the constant $c$ even appear in Newtonian Gravity.
Maxwell has $\epsilon_0$ and $\mu_0$ from which you can make $c$. And General Relativity and Special Relativity have $c$ directly as a constant of the theory. But Newtonian Gravity has no speed, it only has one constant, $G,$ and the units of $G$ are $\mathrm{kg^{-2}N}.$