- #1
Hiero
- 322
- 68
I’m sure the resolution is something to the effect of “we can only apply special relativity in flat spacetime” but I’m hoping someone can explain in more detail.
Disclaimer: I don’t know general relativity.
So in a positively curved universe, if you keep traveling (let us neglect expansion) you will eventually come back to where you started?
This seems to present a paradox. Consider two inertial(?) observers in relative motion. They both see each other moving in slow motion (time dilation). This is normally not paradoxical because they can never compare clocks to see who really slowed down without one accelerating (thus breaking the symmetry) like in the twin ‘paradox.’ But in a positively curved universe they would come back to each other without ever changing their state of motion. So they would both expect the other to have had less time elapse on their clocks.
The only resolution I can think of is to say that a curved universe implies a universal rest frame? So that the one who is truly at rest (or I suppose, moving slower) is the one who ages more?
Appreciate any insight into this revised version of the twin paradox.
Disclaimer: I don’t know general relativity.
So in a positively curved universe, if you keep traveling (let us neglect expansion) you will eventually come back to where you started?
This seems to present a paradox. Consider two inertial(?) observers in relative motion. They both see each other moving in slow motion (time dilation). This is normally not paradoxical because they can never compare clocks to see who really slowed down without one accelerating (thus breaking the symmetry) like in the twin ‘paradox.’ But in a positively curved universe they would come back to each other without ever changing their state of motion. So they would both expect the other to have had less time elapse on their clocks.
The only resolution I can think of is to say that a curved universe implies a universal rest frame? So that the one who is truly at rest (or I suppose, moving slower) is the one who ages more?
Appreciate any insight into this revised version of the twin paradox.