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Dec13-11, 12:23 PM
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Matterwave's Avatar
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Quote Quote by atyy View Post
Gravity in Newton is described only by one number at each point in space, whereas in GR it is described by 10 numbers at each point in spacetime.

In GR, relative velocities are only defined between objects whose worldlines intersect in spacetime. Let's call that the local velocity. The local velocity of a massive object in freefall never exceeds the speed of light, even as it approaches the singularity.

What goes faster than light in GR? It depends on the definition of "what" and "goes", but there is a sense in which space itself falls faster than light into a black hole.
Man you gotta be spending all your spare time on Arxiv cus you always have a paper ready...XD