Gravitational energy

From Wikipedia, the free encyclopedia

Gravitational energy is the energy associated with the gravitational field. Between two or more masses (or other forms of energy-momentum) a gravitational potential energy exists, according to Newtonian physics. Conservation of energy requires that this gravitational potential field energy is always negative.^[1]

The use of the Landau-Lifshitz combined matter+gravitational stress-energy-momentum pseudotensor^[2] allows the energy-momentum conservation laws to be extended into general relativity. Subtraction of the matter stress-energy-momentum tensor from the combined pseudotensor results in the gravitational stress-energy-momentum pseudotensor. 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.

[edit] References

1. ^ 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.
2. ^ Lev Davidovich Landau & Evgeny Mikhailovich Lifshitz, The Classical Theory of Fields, (1951), Pergamon Press, ISBN 7-5062-4256-7