The relationship between Stress-Energy tensor and Mass

In summary, the Stress-Energy tensor is responsible for curving Space-Time and is associated with every mass distribution. The relationship is explained in the Wikipedia page for Einstein field equations, where the nonzero components of the tensor are described for a perfect fluid at rest. The off diagonal terms represent shear stresses and there is also momentum density for a moving object or fluid.
  • #1
ShayanJ
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In Einstein field equations,the term that is responsible for curving Space-Time is the Stress-Energy tensor.But we know that mass should be able to curve space-time.So I think every mass distribution should have a Stress-Energy tensor associated with it.
What is that relationship?
Thanks
 
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  • #2
Volumic mass density is the 00 component of the stress-energy tensor.
 
  • #3
Shyan said:
In Einstein field equations,the term that is responsible for curving Space-Time is the Stress-Energy tensor.But we know that mass should be able to curve space-time.So I think every mass distribution should have a Stress-Energy tensor associated with it.
What is that relationship?
Thanks

The relationship is explained in Wikipedia here: http://en.wikipedia.org/wiki/Stress–energy_tensor

The simplest case is a perfect fluid at rest. In that case, the nonzero components of the stress-energy tensor [itex]T^{\alpha \beta}[/itex] are:
[itex]T^{0 0} = \rho[/itex], where [itex]rho[/itex] is the mass-energy density, and
[itex]T^{1 1} = T^{2 2} = T^{3 3} = p[/itex], where [itex]p[/itex] is the pressure.
 
  • #4
dextercioby said:
Volumic mass density is the 00 component of the stress-energy tensor.
Energy density, which is proportional to mass density only for a body at rest.
 
  • #5
Thanks guys
But what about other components?
 
  • #6
Shyan said:
Thanks guys
But what about other components?

As I said, for a fluid at rest, the three spatial components of the stress-energy tensor are just the pressure.
 
  • #7
Shyan said:
But what about other components?

The diagram on the Wikipedia page identifies what the various components (or groups of them) represent.
 
  • #8
Shyan said:
Thanks guys
But what about other components?

In addition to what Steven said, the off diagonal terms are shear stresses.
 
  • #9
And of course you have momentum density...if you have a moving object or fluid.
 

1. What is the Stress-Energy tensor?

The Stress-Energy tensor is a mathematical object used in the theory of general relativity to describe the distribution of energy and momentum in spacetime. It includes components for energy density, momentum density, and stress (pressure and tension).

2. How is the Stress-Energy tensor related to mass?

The Stress-Energy tensor is directly related to mass through Einstein's famous equation, E=mc^2. This equation states that mass and energy are equivalent and can be interconverted. The components of the Stress-Energy tensor represent different forms of energy, including mass-energy.

3. What is the significance of the Stress-Energy tensor in general relativity?

The Stress-Energy tensor is crucial in general relativity as it describes the curvature of spacetime caused by the distribution of matter and energy. This curvature is what we experience as gravity. In other words, the Stress-Energy tensor determines the gravitational field in a given region of spacetime.

4. Can the Stress-Energy tensor be used to predict the motion of objects?

Yes, the Stress-Energy tensor can be used to predict the motion of objects in the presence of a gravitational field. This is because the curvature of spacetime caused by the Stress-Energy tensor dictates the path that objects will follow in space.

5. How is the Stress-Energy tensor calculated?

The Stress-Energy tensor is calculated using the Einstein field equations, which relate the curvature of spacetime to the distribution of matter and energy through the Stress-Energy tensor. The precise calculation depends on the specific physical system being studied.

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