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### General Relativity and cosmology [duplicate]

What is the physical meaning of Ricci scalar is a covariantly constant?
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### Why do we say “Spacetime Curvature is Gravity”?

Although "Spacetime Curvature is Gravity" is the first statement that is told to an infant by the "popular science", I believe that really really misrepresents what GR has to say. I am posting this ...
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### What would happen if the light-speed was higher? [closed]

I came across a rather interesting passage in a book attempting to debunk Darwin's Theory of Evolution from a Christian viewpoint. One thing the book suggested, was that various scientific ways to ...
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### What does the Ricci tensor represent?

I'm new to this site so I am sorry if I get the format wrong. However, I'm having some trouble understanding the Ricci tensor. I know it is found by contracting the Riemann tensor and that this is ...
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### What is the geometrical interpretation of Ricci tensor?

In differential geometry and general relativity space is said to be flat if the Riemann tensor $R=0$. If the Ricci tensor on manifold $M$ is zero, it doesn't mean that the manifold itself is flat. So ...
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### What is a Christoffel symbol?

What is a Christoffel symbol? I often see that Christoffel symbols describe gravitational field and at other times that they describe gravitational accelerations. Then, on some blogs and forums, ...