How is the Einstein field equation converted to its tensor form?

In summary, drphysics explains that in order for the equation ∇2g00 = 8πGρ to fit general relativity, we need to change it to Gμv = 8πGTμv. The energy density, T00, is converted from ρ using the formula ρ=E/c2. However, since T00 is a tensor, the conversion is done over c4 instead of c2. This is because the factor of c4 is used for unit conversion, assuming conventional units of energy density for the right-hand side of the field equation and units of curvature for the left-hand side.
  • #1
TimeRip496
254
5
2g00 = 8πGρ

According to drphysics, as this is not a tensor equation, we need to change it such that it fits general relativity.

Gμv = 8πGTμv

T00 is the energy density. The conversion of the density(ρ) to T00 is it done through E=mc2?

ρ=E/c2

And since is T00, it will be over c4 instead of c2. Is this how we add c4 to this equation(∇2g00 = 8πGρ) as we convert it to its tensor form?

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  • #2
The factor of ##c^4## is for unit conversion; it assumes that you are using conventional units of energy density for the RHS of the field equation and units of curvature (inverse length squared) for the LHS. A quantity with units of energy density is converted to units of curvature by multiplying by ##G / c^4##. (If the RHS is in units of mass density instead, the factor will be ##G / c^2##.)
 

Related to How is the Einstein field equation converted to its tensor form?

1. What is the Einstein Field Equation?

The Einstein Field Equation is a set of mathematical equations developed by Albert Einstein as part of his theory of general relativity. It describes how matter and energy interact with the fabric of space-time, and how this interaction produces the force of gravity.

2. Why is the Einstein Field Equation important?

The Einstein Field Equation is important because it provides a more accurate and comprehensive understanding of gravity than Newton's Law of Universal Gravitation. It has also been confirmed by numerous experiments and observations, making it a fundamental principle of modern physics.

3. How is the Einstein Field Equation derived?

The Einstein Field Equation is derived from Einstein's theory of general relativity, which is based on the principle that the laws of physics should be the same for all observers regardless of their relative motion. The equation combines the concepts of space-time curvature and the energy-momentum tensor to describe how matter and energy influence the geometry of space-time.

4. What does the Einstein Field Equation tell us about the universe?

The Einstein Field Equation provides a framework for understanding the large-scale structure and behavior of the universe. It has been used to explain phenomena such as the expansion of the universe, the bending of light by massive objects, and the existence of black holes.

5. Are there any limitations to the Einstein Field Equation?

While the Einstein Field Equation has been incredibly successful in describing gravity, it has its limitations. It does not account for the effects of quantum mechanics, and it breaks down at extreme conditions, such as inside black holes. Scientists are still working to develop a more complete theory that can reconcile general relativity with quantum mechanics.

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