Twins paradox confusion

  • Thread starter Xeinstein
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Main Question or Discussion Point

I am having trouble understanding how the explanation of the paradox solves the problem. What if people in two different frames were moving wrt one another with constant velocity. Say for instance, these people never turn around to meet up once again and are constantly moving at a constant velocity wrt one another.

Clearly, each will percieve the other's frame to be moving more slowly than their own. There is never a change in reference frame so they disagree on who is older. Who is actually older???? Are they both younger and both older simultaneously? That seems to be a weird consequence of relativity. What am I missing here?

Also, I know the speed of light is constant in all inertial frames. However, it does not necessarily have to be constant in accelerated frames, correct? I believe this because the postulate of relativity states that "all laws of physics are the same in all inertial reference frames", so some laws of physics are not the same in accelerated reference frames, and therefore the speed of light is not necessarily constant in all reference frames, but it is only constant in inertial frames?
 

Answers and Replies

  • #2
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Your just making it harder for your self by thinking of it that way...
 
  • #3
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your missing that things dont age like we do... objects age only by observing the difrence from one preceptable frame to another :/ please refine your other questions :/
 
  • #4
JesseM
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I am having trouble understanding how the explanation of the paradox solves the problem. What if people in two different frames were moving wrt one another with constant velocity. Say for instance, these people never turn around to meet up once again and are constantly moving at a constant velocity wrt one another.

Clearly, each will percieve the other's frame to be moving more slowly than their own. There is never a change in reference frame so they disagree on who is older. Who is actually older???? Are they both younger and both older simultaneously? That seems to be a weird consequence of relativity. What am I missing here?
Simultaneity between distant events isn't objective in relativity, that's what is meant by the relativity of simultaneity--If we are light-years apart, then in one frame the event of my turning 30 can be simultaneous with the event of your turning 40, in another frame the event of my turning 30 can be simultaneous with the event of your turning 20. Asking who is "really" older in this case would be like asking which of two objects moving slower than light is "really" moving at a greater speed, in relativity these questions are frame-dependent so there simply is no single correct answer.
Xeinstein said:
Also, I know the speed of light is constant in all inertial frames. However, it does not necessarily have to be constant in accelerated frames, correct?
That's correct.
 
  • #5
JesseM
Science Advisor
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your missing that things dont age like we do... objects age only by observing the difrence from one preceptable frame to another :/ please refine your other questions :/
That doesn't really make any sense. Any object that you can attach a clock to can be said to age exactly like we do, with the age just defined as the elapsed time on the clock.
 
  • #6
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play with a tape recorder, and record your self talking at a slower turning speed. then play it back at a faster turning speed. your voice would be slower. do the oppisite and it would be faster
 
  • #7
JesseM
Science Advisor
8,492
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play with a tape recorder, and record your self talking at a slower turning speed. then play it back at a faster turning speed. your voice would be slower. do the oppisite and it would be faster
What do tape recorders have to do with Xeinstein's question?
 

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