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Worldline
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why general relativity can't define any tensorial expression for Gravitational energy momentum density ?
pervect said:Viewed in this standpoint, the lack of a global energy in GR is due to the lack, in general, of a global time translation symmetry.
Worldline said:Thanks for ur answers, But in Teleparallel Gravity we can easy define an energy-momentum tensor for gravity. So it seems that the impossibility of defining an energy-momentum tensor isn't a characteristic of gravity, but a property of geometrical picture of GR
The gravitational energy-momentum tensor, also known as the stress-energy tensor, is a mathematical tool used in Einstein's theory of general relativity to describe the distribution of matter and energy in space-time. It represents the mass, energy, and momentum of a system, including the effects of gravity.
The gravitational energy-momentum tensor is calculated by solving Einstein's field equations, which relate the curvature of space-time (described by the metric tensor) to the distribution of matter and energy (described by the energy-momentum tensor). This is a complex mathematical process that involves taking into account all sources of matter and energy in a given system.
The gravitational energy-momentum tensor is significant because it allows us to understand the effects of gravity on the behavior of matter and energy. It is a crucial component of Einstein's theory of general relativity, which has been incredibly successful in explaining the behavior of large-scale structures in the universe.
Unlike other forms of energy and momentum, the gravitational energy-momentum tensor cannot be directly measured or observed. However, its effects can be observed through the curvature of space-time, which can be measured using instruments such as gravitational wave detectors.
The gravitational energy-momentum tensor has many practical applications in modern physics and astrophysics. It is used to study the behavior of objects in the universe, such as stars and galaxies, and to make predictions about the evolution of the universe. It also plays a crucial role in the development of technologies such as GPS, which rely on precise measurements of space-time curvature.