## The relationship between Stress-Energy tensor and Mass

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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 Blog Entries: 9 Recognitions: Homework Help Science Advisor Volumic mass density is the 00 component of the stress-energy tensor.

 Quote by Shyan 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%...3energy_tensor

The simplest case is a perfect fluid at rest. In that case, the nonzero components of the stress-energy tensor $T^{\alpha \beta}$ are:
$T^{0 0} = \rho$, where $rho$ is the mass-energy density, and
$T^{1 1} = T^{2 2} = T^{3 3} = p$, where $p$ is the pressure.

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## The relationship between Stress-Energy tensor and Mass

 Quote by dextercioby 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.
 Thanks guys But what about other components?

 Quote by Shyan 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.

Mentor
 Quote by Shyan But what about other components?
The diagram on the Wikipedia page identifies what the various components (or groups of them) represent.

 Quote by Shyan Thanks guys But what about other components?
In addition to what Steven said, the off diagonal terms are shear stresses.
 Recognitions: Science Advisor Staff Emeritus And of course you have momentum density....if you have a moving object or fluid.