Twin paradox not a paradox?

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  • #51
Ibix
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I can remain in motion for 20 years, accelerate for one second, and then revert to inertial motion. It's not one or the other, all the time.
Of course. What you cannot do is stitch together the two implied inertial frames without doing so carefully. Did you carry out the computation I suggested in post #44 yet?
And the one second doesn't change the prior 20 years.
If you use the inertial frame in which you were at rest, and then naively switch to the inertial frame in which you are at rest after the acceleration, you've just changed your definition of "at the same time". It doesn't affect your history, but it does affect your assessment of what time it is elsewhere - and you fail to account for this change in assessment at your peril.
The spacetwin is treated as if his motion in inertial the whole time.
You are treating him as such, yes. And you are finding paradoxes. Perhaps you should consider not treating him as such and see if the paradoxes go away? As we've been telling you for the last hour or two?
It is a serious mistake to say that is is not inertial because he had to accelerate to achieve his crusing speed.
It's a mistake to describe someone as not inertial because he's not inertial?
 
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  • #52
Orodruin
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You DO give a standard of rest, every time you calculate a lorentz transformation. YOU are at absolute rest, then.
This is also not correct. The Lorentz transformation relates two inertial frames, it says absolutely nothing about absolute rest.

I don't know what your background is or who you think you are debating this with, but you should understand that you are talking with actual physicists. Some of which teach relativity at university level.
 
  • #53
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. This will result in the same prediction as that of the Earth twin.

Having the same "prediction" is not really even the problem. This is the paradox, not the resolution to it. The fact that they do agree (which they will be forced to once they reunite and compare clocks) is the problem.

They both agree that one clock was slower, the other faster. This is tantamount to them agreeing about which one was moving, whether they predicted it, or not. As it turns out, the earth twin did predict it accurately. But, either way, the clock difference, and hence the motion associated with it, is ABSOLUTE, not relative. It is unilateral, not reciprocal.

I can't make much sense out of the rest of your post.
 
  • #54
Ibix
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This is tantamount to them agreeing about which one was moving, whether they predicted it, or not.
No. It's tantamount to agreeing that at least one of them was not inertial for the whole time. Because that is a correct conclusion.
 
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This is also not correct. The Lorentz transformation relates two inertial frames, it says absolutely nothing about absolute rest.

What are you trying to say here? The obvious?

Yes, two frames are involved, one of which is deemed to be stationary, and the other moving. You're just making my point for me.
 
  • #56
Ibix
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I can't make much sense out of the rest of your post.
In that case, I suggest you look up the relativity of simultaneity. And/or carry out the calculation I suggested in post #44.
 
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Orodruin
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Having the same "prediction" is not really even the problem. This is the paradox, not the resolution to it. The fact that they do agree (which they will be forced to once they reunite and compare clocks) is the problem.
This is a lie. The classic paradox is that, failing to account for the relativity of simultaneity, you would get different predictions. That the theory actually predicts the same time difference just means that it is a consistent theory and not paradoxical at all.

You also seem to insist that there is something special about the Earth frame. There is not. You could start with the space twin going away and the Earth twin then blasting after him to catch up. If you did so the space twin would be older when they meet.

Yes, two frames are involved, one of which is deemed to be stationary, and the other moving. You're just making my point for me.
No. You are just interpreting it that way, but you are wrong. The Lorentz transformation says exactly nothing about one of the frames being "stationary". Claiming anything else is a lie.
 
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In that case, I suggest you look up the relativity of simultaneity. And/or carry out the calculation I suggested in post #44.

I don't have to "look it up." Nor do I have to accept that bogus notion as being determinative. It is relative simultaneity which creates all the "paradoxes" because it's ultimately inconstent. Only a presumption of absolute simultaneity, as is used in the GPS, can generate consistenly accurate predictions of time dilation
 
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I can't make much sense out of the rest of your post.
Then you should probably sit down and take a deep breath, because it means that you are seriously confusing yourself in regards to SR, what it says, and what is paradoxical or not.

I don't have to "look it up." Nor do I have to accept that bogus notion as being accurate. It is relative simultaneity which creates all the "paradoxes" because it's ultimately inconstent.
No it is not ultimately inconsistent. Your insistence on this is. Do you really think something like that would have eluded physicists for over 100 years?

Only a presumption of absolute simultaneity, as is used in the GPS, can generate consistenly accurate predictions of time dilation
This is simply wrong. There is no assumption of absolute simultaneity in GPS. There is a choice of coordinates, which is definitely not the same thing. Every post you have made here has just suggested to me that you do not have the faintest idea about what you are talking about.
 
  • #60
Ibix
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Only a presumption of absolute simultaneity, as is used in the GPS
The GPS does not assume absolute simultaneity. If it did, it wouldn't have to go through the whole rigmarole of defining a master clock and specifying which frame's simultaneity convention it uses.
Nor do I have to accept that bogus notion as being accurate.
OK - you aren't required to accept anything.

I'm out of this conversation at this point. You clearly don't understand SR, and I've pointed out repeatedly what you are doing wrong (applying results from inertial frames to non-inertial frames). At this point, if you won't consider revising your ideas to see if the paradoxes go away (they do) then I can't help you.
 
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You are just interpreting it that way, but you are wrong. The Lorentz transformation says exactly nothing about one of the frames being "stationary". Claiming anything else is a lie.

It doesn't, eh? Let say that, using radar guns, A and B both agree that they are moving at the rate of .6c relative to each other.

Now, tell me, who does all that speed get attributed to when you perform an LT calculation?

Hint, one frame has an attributed speed of zero, the other an attributed speed of .6c.
 
  • #62
Doc Al
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Enough already. Thread closed for moderation.
 
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