Closed Universe Twins Paradox: No Acceleration?

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Discussion Overview

The discussion revolves around the implications of a closed universe on the twins paradox, particularly focusing on whether the paradox persists if neither twin experiences acceleration. Participants explore the nature of the universe, time dilation, and the conditions under which the twins might reunite.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant questions whether the twins paradox remains a paradox in a closed universe where neither twin accelerates, suggesting this could imply such a universe does not exist.
  • Another participant raises the point that the universe's expansion complicates the scenario, proposing that if the universe is infinite, the likelihood of a duplicate traveler existing is certain, which may affect the uniqueness of the argument.
  • A different viewpoint suggests that as long as the universe does not expand faster than the traveler, the twins will eventually meet again, regardless of the universe's topology.
  • One participant references a paper that discusses the resolution of the twins paradox in a universe with compact dimensions, arguing that the paradox can be resolved through the existence of a preferred inertial reference frame, which breaks global Lorentz invariance.
  • Another participant mentions that proper application of Special Relativity resolves the twins paradox, indicating that it should not be considered a paradox in this context.

Areas of Agreement / Disagreement

Participants express differing views on whether the twins paradox is resolved in a closed universe and whether the universe's expansion affects the scenario. There is no consensus on the implications of a closed universe for the twins paradox, and multiple competing perspectives remain.

Contextual Notes

Discussions include assumptions about the nature of the universe (closed vs. infinite) and the implications of time dilation and acceleration. The references to various papers and previous discussions indicate a reliance on specific theoretical frameworks that may not be universally accepted.

infinitus
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If the universe was closed and such that if one continued in a straight line they would arrive where they began eventually. Wouldn't the twins paradox still be a paradox as neither party is accelerating (are they?) and this would prove that such a universe doesn't exist?
 
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hmmmmm time dilation, well who is to say that the universe is finite in the first place. considering that we know it is currently expanding(because the gallixys are moving apart) its not to hard to fathom the fact that it may be infinitely big in porportion and that it is getting biger even as we speak.
 
As long as it isn't expanding faster then the traveller they will still met again if the universe is as suggested in my original post.
 
infinitus said:
As long as it isn't expanding faster then the traveller they will still met again if the universe is as suggested in my original post.
But if the universe is infinite the odds of a duplicate of your traveler existing is 1 , so you argument is not unique to a closed as the same result can be expected in an infinite universe.

I do not see how the "twin paradox" enters into this. Proper application of Special Relativity resolves the "twin paradox", so it is not a paradox.
 
infinitus said:
If the universe was closed ... wouldn't the twins paradox still be a paradox ... and this would prove that such a universe doesn't exist?
The paper, "On the Twin Paradox in a Universe with a Compact Dimension" presents a very clear answer to your question:

"We consider the twin paradox of special relativity in a universe with a compact spatial dimension. Such topology allows two twin observers to remain inertial yet meet periodically. The paradox is resolved by considering the relationship of each twin to a preferred inertial reference frame which exists in such a universe because global Lorentz invariance is broken. The twins can perform 'global' experiments to determine their velocities with respect to the preferred reference frame (by sending light signals around the cylinder, for instance)."
http://arxiv.org/PS_cache/gr-qc/pdf/0503/0503070.pdf

See these references also:

http://physics.ucr.edu/Active/Abs/abstract-13-NOV-97.html
http://www.everythingimportant.org/viewtopic.php?t=79
http://cornell.mirror.aps.org/abstract/PRD/v8/i6/p1662_1
http://arxiv.org/PS_cache/gr-qc/pdf/0101/0101014.pdf
http://arxiv.org/PS_cache/physics/pdf/0006/0006039.pdf
http://www.everythingimportant.org/viewtopic.php?t=605
http://www.everythingimportant.org/relativity/simultaneity.htm

All this analysis has a pointed answer:

When the two twins meet again, the youngest, least-aged twin will be the one who is moving the fastest with respect to the absolute frame of reference.

Here's the main point:

Spatially compact spacetimes break global Lorentz invariance and define absolute inertial frames of reference.
 
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