# The Naked Scientists Forum

### Author Topic: The remote triplet conundrum  (Read 298 times)

#### jeffreyH

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##### The remote triplet conundrum
« on: 24/07/2016 20:45:40 »
The twin paradox is said to resolve because of the accelerations at the start and turning point of the travelling twins journey. Let us consider 3 remote triplets. Triplets only because at certain positions in spacetime 2 out of 3 of them will have exactly the same age. The thought experiment proceeds this way. The first triplet is on earth. We have engineered a situation such that the second triplet will pass by the earth at 0.99c at exactly the instant that his and the earthbound triplets ages are the same. The second triplet then journeys x number of light years to a point where we have engineered a third triplet to pass by the second on a path back to earth. This third triplet also travels at 0.99c and is exactly the same age as triplet 2 when they pass each other. The question is how do triplets 1 and 3 compare agewise when they meet up at earth. Since no inertial frame is more preferred than any other both will see the other as aging slower. This cannot be so. We have removed the convenience of accelerating frames so what is the resolution?

#### alancalverd

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##### Re: The remote triplet conundrum
« Reply #1 on: 24/07/2016 23:26:42 »
How did you arrange for T2 to reach 0.99c with respect to T1, without an accelerating frame of reference?

#### PhysBang

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##### Re: The remote triplet conundrum
« Reply #2 on: 25/07/2016 00:14:43 »
We have removed the convenience of accelerating frames so what is the resolution?
No, you haven't. If any triplet comes near any other, then you have acceleration.

#### jeffreyH

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##### Re: The remote triplet conundrum
« Reply #3 on: 25/07/2016 00:18:27 »
There you have hit on the pertinent point. One that has been occupying me. When does an accelerating frame become an inertial frame. The answer of course is when forces are no longer applied. Does it matter at which point this happens or is it as counter intuitive as quantum mechanical effects?

#### jeffreyH

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##### Re: The remote triplet conundrum
« Reply #4 on: 25/07/2016 00:19:28 »
We have removed the convenience of accelerating frames so what is the resolution?
No, you haven't. If any triplet comes near any other, then you have acceleration.

That sound like hair-splitting.

#### jeffreyH

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##### Re: The remote triplet conundrum
« Reply #5 on: 28/07/2016 18:36:17 »
The points raised in the above posts by Alan and PhysBang are at the heart of the so called twin paradox. What saves the day is a changing frame. One that can no longer be considered inertial. I am not convinced that this is at all satisfactory. I may be in a very tiny minority of individuals that are likely to think this. To be honest a lot may be cranks. So why would I place myself in such distinguished company? I believe that something needs to be added to relativity. That something is missing. If only I knew what that was!

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##### Re: The remote triplet conundrum
« Reply #5 on: 28/07/2016 18:36:17 »