Gravitational energy

Gravitational energy is the energy associated with the gravitational field.

According to classical mechanics, between two or more masses (or other forms of energy-momentum) a gravitational potential energy exists. Conservation of energy requires that this gravitational potential field energy is always negative. [Alan Guth" The Inflationary Universe: The Quest for a New Theory of Cosmic Origins" (1997), Random House , ISBN 0-224-04448-6 Appendix A: "Gravitational Energy" demonstrates the negativity of gravitational energy.]

In general relativity gravitational energy is modeled via the Landau-Lifshitz pseudotensor [Lev Davidovich Landau & Evgeny Mikhailovich Lifshitz, "The Classical Theory of Fields", (1951), Pergamon Press, ISBN 7-5062-4256-7 ] which allows the energy-momentum conservation laws of classical mechanics to be retained. Addition of the matter stress-energy-momentum tensor to Landau-Lifshitz pseudotensor results in a combined matter plus gravitational energy pseudotensor which has a vanishing divergence. Some people object to this derivation on the grounds that pseudotensors are inappropriate in general relativity, but this treatment only required, in the conservation law, the use of the "derivative" of the combined pseudotensor which was, in this case, in fact a tensor! A [http://gravitywaves.0pixel.net/ study] , based on not unlike the times tide of sun and moon shows, directly, that the speed of gravity is equal to the speed of light.This means that the force of gravity is a wave electromagnetic that is travelling at 300.000 km for second.

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