How, John S. Bell preferred to teach special relat

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16 years 9 months ago #16151 by tvanflandern
Bell's example reflects a failure to understand special relativity. It goes wrong in this sentence:

"Then (as reckoned by an observer in A) they will have at every moment the same velocity, and so remain displaced one from the other by a fixed distance."

That condition cannot be maintained for B and C because they each are at a different moment of existence. If B precedes C, then B will be doing its accelerations in the relative past and C in the relative future, as judged by A.

If you don't accept relativity's premises, that's fine. Special relativity is a falsified theory. But you (and Bell) can't argue that it has a logic problem when you deny the premises on which the theory is built. One of those premises means that there is no such thing as remote simultaneity between frames. -|Tom|-

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16 years 9 months ago #19852 by Leo Vuyk
Replied by Leo Vuyk on topic Reply from
I realize that there is a problem.
At the moment of the start signal given form A to B and C, A is not able any more to measure the reality of B and C.
However because it is a gedanken experiment, we ( John Bell) did accept that B and C are instructed beforehand to accellerate in an exact same way.

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16 years 9 months ago #20524 by Stoat
Replied by Stoat on topic Reply from Robert Turner
I fail to understand this argument at all. The two ships accelerate to some near light velocity and they are going in the same direction. That surely means the two ships are one ship, the thread is part of the this one ship. As one ship, all of its constituent parts are in the same inertial frame. The thread won't break.

What would be better, I think, would be to consider two ships acting as tugs for the third. They use super thread to pull the third ship. As tugs they can pay out more thread, for when they want to use their momentum to steer the hulk ship. Micro relativistic observers would see an infinite number of vector resultant movements of the three craft. Now that would be the case if the speed of light was an absolute. Given a speed of gravity which is almost instant, the observers would be able to map their co-ordinate systems in one to one correspondence with each other and hence arrive at an agreed series of movements for the three craft.

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16 years 9 months ago #19853 by tvanflandern
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Leo Vuyk</i>
<br />B and C are instructed beforehand to accelerate in an exact same way.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">What does "exact same way" mean when time for B and C is not the same? From A's perspective, the lead ship exists in the past relative to the trailing ship. Something similar is true for B and C because their acceleration means that they are never in the same frame. (In SR, there is no such thing as "a universal instant of NOW".) -|Tom|-

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16 years 9 months ago #20868 by Leo Vuyk
Replied by Leo Vuyk on topic Reply from
John Bell thought the smae frame problem could be solved, that is why he wrote:
they "drift freely in a region of space remote from other
matter, without rotation and without relative motion, with B and C
equidistant from A".

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16 years 9 months ago #20651 by tvanflandern
<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Leo Vuyk</i>
<br />they "drift freely in a region of space remote from other
matter, without rotation and without relative motion, with B and C
equidistant from A".<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">That's the starting condition, when all are in the same frame. As soon as the accelerations start, they are all in different frames, and it is useless to claim that B and C accelerate "at the same time" because there is no such thing as remote simultaneity in SR. -|Tom|-

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