All Questions
6
questions
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Is the non-simply connected version of AdS space a maximally symmetric spacetime?
A common construction of anti-de Sitter space is the following:
Start with the flat five-dimensional manifold with metric $ds_5^2 = -du^2 - dv^2 + dx^2 + dy^2 + dz^2$.
Consider the hyperboloid ...
- 48.4k
1
vote
1
answer
243
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Common misunderstanding of Birkhoff Theorem
I just found a paper "On a common misunderstanding of the Birkhoff theorem". This means that inside a spherically symmetric thin shell there is no gravitational force, BUT there is time ...
- 770
0
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0
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66
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Curvature and Symmetries of spacetime
Is there any relation between symmetries of spacetime and the curvature invariants? For example is spherical symmetric spacetimes, necessarily have positive curvature? Could we define any spherical ...
- 159
2
votes
2
answers
266
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Einstein equations in the spherically symmetric, static case
This question is not about the solutions but much rather about the equations we write in GR for a spherically symmetric, static vacuum 4D spacetime.
The Einstein equations are
$$G_{\mu\nu}=0\;\;\;\...
- 1,874
5
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1
answer
158
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Assuming a fixed total mass, will the spacetime geometry outside a spherical mass distribution depend on the shape (of the distribution)?
Consider two independent spheres of equal masses but of different radius and in different spacetimes. The first sphere is less dense than the second one, i.e., it has a larger radius. For example, if ...
- 51
2
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Examples of manifolds (not) being: flat, homogeneous and isotropic
I am looking for (at least) one example of the following manifolds:
Flat, homogeneous and isotropic
Curved, homogeneous and isotropic
Flat, non-homogeneous and isotropic
Flat, homogeneous and non-...
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