I put together two questions :(adsbygoogle = window.adsbygoogle || []).push({});

a) suppose there is a point mass with mass M..if it is moving, then from a certain oberver, the total energy is higher, via E=Mc^2...hence, following the generaly relativity qualitatively, where the energy density defines the curvature, the gravitation should be different ?

b) let's take two coordinate systems, linked by a transformation, how are the metric obtained as solution linked together : [tex] x^\mu=f^\mu(x'^\nu)[/tex] how are the [tex]g_{\mu\nu}[/tex] linked to the [tex]g'_{\mu\nu}[/tex]...since the tensor is symmetric, there are only 6 degree of freedom, and hence there should exist 6 degree of functional degree of freedom for the coordinates. Those should hence describe the same space-time. (e.g. Shwarzschild(singular)<->Kruskal(non singular))..Or the question can be stated as : how to know that 2 metrics cannot be obtained by a change of coordinates ?

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# Functional independence and energy

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