How do I use Einstein's field equations to solve for particle locations?

In summary, to use Einstein's field equations to solve for particle locations, one must use the Einstein tensor R, which is equivalent to the Ricci tensor. This tensor represents the deviation of the volume element of a geodesic ball in a curved Riemannian manifold from that of a standard ball in Euclidean space. The inverse metric tensor g is also important in determining curvature and placement. Newton's gravitational constant G is also involved in the calculations. For practical use, the Linearized field equations and the geodesic equation are used to calculate particle trajectories.
  • #1
Petyab
20
0
Can somebody explain a little bit about how to actually use Einstein's field equations to solve for particle locations?

Relevant information:
parentheses are sub-scripts
R(uv)-1/2guvR+guv(cosmological constant sign)=(8piG/c^4)T(uv)

where R is the Einstein Tensor

R is described by wikipedia as the same as the Ricci tensor

R(uv) is the Ricci Tensor

The Ricci tensor is described by wikipedia as "represents the amount by which the volume element of a geodesic ball in a curved Riemannian manifold deviates from that of the standard ball in Euclidean space." (wikipedia, October 16th, 2011) But what if it doesn't deviate? Should a value of near zero be used?

g(uv) is the inverse metric tensor which seems to be an important part that deals with the causal mathematical discription of curvature, placement, and so forth.


G is Newton's gravitational constant

Hey, I kind of get this...take the value...use it.

T(uv) is the stress energy tensor

This is connected with the flux of energy against and amongst objects.

I know it's hard mathematics and there's a lot involved but it seems that two of the big things should be near zero and so I'm wondering how to get the other parts to make more sense...help?
 
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  • #2
For practical use of GR, the Linearized field equations are fine. These are just like Maxwell's equations and are more familiar. To calculate the trajectories of particles you really just want the geodesic equation, which is not strictly related to the field equations.
Linearized Gravity:
[tex]
\Box g_{\alpha\beta}=\frac{16\pi G}{c^4}T_{\alpha\beta}
[/tex]
geodesic equation
[tex]
\frac{\partial u^{\alpha}}{\partial x^{\beta}}+\Gamma^{\alpha}_{\beta\gamma}u^{\gamma}=0
[/tex]
 

1. What are Einstein's field equations?

Einstein's field equations refer to a set of ten equations in Albert Einstein's theory of general relativity. These equations describe the relationship between the curvature of space-time and the presence of matter and energy.

2. Why are Einstein's field equations important?

Einstein's field equations are important because they provide a mathematical framework for understanding the structure of space-time and how it is affected by the presence of matter and energy. They are also crucial in predicting and explaining various astronomical phenomena, such as black holes and gravitational waves.

3. How were Einstein's field equations developed?

Einstein's field equations were developed by Albert Einstein in 1915 as part of his theory of general relativity. He spent nearly a decade working on these equations, which were a major breakthrough in our understanding of gravity and the universe.

4. Can Einstein's field equations be solved?

Yes, Einstein's field equations can be solved, but it is a complex and challenging task. Many solutions have been found over the years, including the famous Schwarzschild solution for a non-rotating, spherically symmetric mass, which describes the space-time around a black hole.

5. How have Einstein's field equations been tested?

Einstein's field equations have been extensively tested and have withstood numerous experiments and observations. Some of the key tests include the precession of Mercury's orbit, the bending of starlight by the Sun's gravity, and the detection of gravitational waves. These tests have confirmed the accuracy and validity of Einstein's theory of general relativity.

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