Is the relativity of simultaneity the reason for time dilation?

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Discussion Overview

The discussion revolves around the relationship between the relativity of simultaneity and time dilation within the framework of special relativity. Participants explore whether one concept causes the other, examining the implications of their interdependence and the conceptual challenges that arise from this relationship.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants argue that understanding the relativity of simultaneity is crucial for grasping time dilation, suggesting that it may contribute to conceptual difficulties faced by students of special relativity.
  • Others propose that both time dilation and relativity of simultaneity arise from the same underlying principles of special relativity, indicating that neither can be said to cause the other.
  • A participant presents an analogy involving a right triangle to illustrate that the relationship between the sides does not imply causation, questioning the formulation of the original question.
  • Another viewpoint suggests that time dilation, when combined with the isotropy of spacetime and the principle of relativity, implies the relativity of simultaneity, presenting a reverse perspective on the causation issue.
  • One participant expresses dissatisfaction with the wording of the question, indicating that it was designed to provoke discussion about mutual time dilation and its connection to simultaneity.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the relativity of simultaneity is the reason for time dilation. Multiple competing views are presented, with some arguing for a causal relationship and others denying it.

Contextual Notes

The discussion highlights various interpretations and assumptions regarding the concepts of time dilation and simultaneity, with no resolution on the implications of their relationship. The complexity of the topic and the differing perspectives contribute to the ongoing debate.

MachPrincipe
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A yes answer can cause conceptual problems. What is your opinion?
 
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This depends on what you put into the concept of time dilation. In the most common approaches, the answer is yes. And it does cause people to have conceptual problems ...
 
MachPrincipe said:
A yes answer can cause conceptual problems. What is your opinion?
I think that "the" reason is too strong of a claim, but certainly understanding the relativity of simultaneity is important for understanding time dilation. Failure to understand the relativity of simultaneity is the key conceptual problem faced by students of SR:

http://arxiv.org/abs/physics/0207081
 
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MachPrincipe said:
A yes answer can cause conceptual problems. What is your opinion?
Metaphorically you could say length contraction and time dilation are two sides of the same coin. That coin is the relativity of simultaneity.
 
MachPrincipe said:
What is your opinion?
That the question is poorly formulated.

Both follow from assuming a particular structure to the universe (pseudo-Riemannian, locally Minkowski) so we can't have one without the other. That doesn't mean that either one has to cause the other.

I'm looking at a 3-4-5 right triangle. Does the fact that one side is of length three and the hypotenuse is of length five "cause" the other side to be of length four? Or does the fact that the two sides have the lengths they do "cause" the hypotenuse to be of length five?
 
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MachPrincipe said:
A yes answer can cause conceptual problems. What is your opinion?

Time dilation and relativity of simultaneity each follow from the postulates, so in that sense neither is the cause of the other.
 
MachPrincipe said:
A yes answer can cause conceptual problems. What is your opinion?

I don't see how the statement can be justified offhand, and no supporting argument has been presented.

One can make a case that the existence of time dilation, combined with the isotropy of space time and the principle of relativity, implies the relativity of simultaneity. Which is the reverse of your original statement. The principle of relativity, combined with isotropy, means that if A is moving at some velocity relative to B, if A sees B's clock time dilated, B must also see A's clock time dilated. This is only possible if the means for comparing clocks depends on the frame of reference, if the method of clock were frame-independent (as it is in Newtonian mechanics), if A's clock ran slow relative to B's clock, it would logically follow that B's clock ran fast relative to A's clock.

Perhaps there is some way to justify the argument in the other direction, but I'm not aware of it offhand.
 
Perhaps there is some way to justify the argument in the other direction, but I'm not aware of it offhand.
The bad wording of the question is intentional. I wanted to see some reference to the mutual time dilation. Basically, one observer can say that it is the other obserrver who sees her moving and time dilated because of relativity of simultaneity, so, in this sense, relativity of simult. can be seen as a «reason» for time dilation. From this case you extrapolate to every single inertial frame, forget that in your calculations you first introduce some time dilation too, and you are done: simultaneity has to do, entirely, with time dilation.
I have seen so many times that I am glad to see the No responses.
In special, I would like to know the arguments of the first response to say Yes, and the exceptions mentioned.
 
MachPrincipe said:
The bad wording of the question is intentional.
That is not acceptable.

Thread closed.
 

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