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Author Topic: Is there a firewall in dense objects with relativistic rotation?  (Read 2425 times)

Offline jeffreyH

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Consider a shaft through a neutron star with a hypothetical observer at the centre of gravity. If his time dilation is such that external photons would appear to violate light speed would the shaft act as an information firewall? No path should be available, at the speed of rotation, for a photon to reach the central observer.
« Last Edit: 18/02/2015 02:33:29 by jeffreyH »


 

Offline PmbPhy

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Consider a shaft through a neutron star with a hypothetical observer at the centre of gravity. If his time dilation is such that external photons would appear to violate light speed would the shaft act as an information firewall? No path should be available, at the speed of rotation, for a photon to reach the central observer.
That's not true. Photons at larger values of r can reach smaller values of r regardless of the fact that observers at the smaller values measure the photons at larger values of r to have a larger coordinate speed of light. In doing so it violates no law of physics.
 

Offline yor_on

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Saw someone using the idea of 'sticks', put down at some origin (source) and at some sink (end station). If you use that then however you measure, accelerating or not, light won't pass 'c' for you. There's only two ways to measure a speed of light in a vacuum, from uniform motion and accelerations. If you are considering it from time dilations, like being very close to lights speed, then the 'container universe' might be evolving (changing) for you, and theoretically you can argue, from 'the eyes of a God' naturally, that this change must take place ftl. But that is using the eye of a God, at the same time as presuming that only one frame of reference (yours) can define this universe. No clocks anywhere change their 'pace' experimentally due to this, locally defined, though. And you won't measure anything else than before. What that leaves one is not a question of where one can place oneself to observe ftl, but a question of how relations allows it. That is as all clocks locally behaves as usual, yours too, which defines it as a result between frames of reference.
 

Offline jeffreyH

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Consider a shaft through a neutron star with a hypothetical observer at the centre of gravity. If his time dilation is such that external photons would appear to violate light speed would the shaft act as an information firewall? No path should be available, at the speed of rotation, for a photon to reach the central observer.
That's not true. Photons at larger values of r can reach smaller values of r regardless of the fact that observers at the smaller values measure the photons at larger values of r to have a larger coordinate speed of light. In doing so it violates no law of physics.

I know exactly what you mean but you are missing my point. If observer A's time is slowed down to 1 tenth that of observer B then to observer A observer B is moving faster than normal. As if a movie is speeded up to 10 times normal speed. Surely he would come to the conclusion that the photons relaying this information to him originated in the faster frame and they too must have been 10 times faster. When the photons get to him he records the correct speed of light but deduction must lead him to the conclusion that light was faster in the other frame by a factor of 10. My point is that this can never be true without a firewall of some kind. This could be exactly this reduction in the velocity of light so that all remote frames appear normal once the light reaches observer A because it has slowed down. We should never be able to visibly confirm time dilation in the same way we can never visibly confirm length contraction.
« Last Edit: 18/02/2015 18:58:24 by jeffreyH »
 

Offline yor_on

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Why do you think we need to invent a firewall for it? It's about frames of reference. What I think you are looking for is the mechanism allowing those different frames to describe a common universe. Maybe one should differ a 'common universe' from a 'commonly agreeable on universe' though? The common universe is the one we observe now and here, the 'commonly agreeable on universe' is the one described by Lorentz transformations, to me.
 

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