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If the thermodynamic arrow of time reverses, the laws of physics should be reversed.Eg: A spaceship enters the event horizon of black hole, it has no chance of escaping the gravitational forceof the black hole. But. if time rewinds, the spaceship escapes the blackhole.So, if we reverse the laws of physics, and by some means, make it work, is it possible to rewind time?
Pmb, if one believes in Einstein's general relativity, he should also treat seriously its theoretical consequences, like living in infinitely thin submanifold of multidimensional something,
black holes with infinite density matter state, wormholes connecting two places of spacetime, warp drive ... or time reversing loops - which theoretically would allow to literally observe "rewinding the time".
I don’t know what you’re talking about. Can you please be specific and give an example of “like living in infinitely thin submanifold of multidimensional”?
That’s not necessarily true. While one can describe the spacetime of such things it need not follow that there exist in nature ways of accomplishing such things. Relativity predicts certain things given certain assumptions. E.g. Yes. I know that there is a metric which describing Warp Drive but nobody knows yet if its theoretically possible to construct one. As I recall the outer surface of the warp drive cannot be causally connected to the inside surface. Therefore there may be no way of controlling such a warp drive. As far as ‘time reversing loops” go they might exist in theory but may not be able to exist in practice. Something similar holds for wormholes.
Imagine 2D sheet with constant positive internal curvature - it just has to enclose into a sphere ... where this sphere is?
It is infinitely thin 2D submanifold of 3D - even if we use only internal curvature like in GRT, it can create structures clearly requiring higher dimensions –
So accordingly to GRT, our spacetime is infinitely thin something in mutidimensional something
And so accordingly to GRT, internal curvature caused by well placed huge amount of mass could theoretically create wormhole of chosen shape ... even if it is completely not realizable by us.
Quote from: Jarek DudaSo accordingly to GRT, our spacetime is infinitely thin something in mutidimensional something I see no reason to make a statement that spacetime is a subspace of something if you can’t define that something and its usefulness.
Wormhole creation, … must be accompanied by closed timelike curves … and also a violation of the “weak energy condition”. .. it is not known whether the stress-energy tensors required by the Einstein equations in those spacetimes are permitted by quantum field theory.