Is the relativity of simultaneity the reason for time dilation?

In summary, the conversation discusses the relationship between time dilation and the relativity of simultaneity in special relativity. Some argue that understanding the relativity of simultaneity is crucial for understanding time dilation, while others believe that both concepts are equally important and follow from the postulates of special relativity. The question posed by one participant is intentionally worded to provoke discussion and ask for supporting arguments, but the conversation ends with a request for clarification on the first response's arguments and exceptions. The thread is then closed.
  • #1
MachPrincipe
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A yes answer can cause conceptual problems. What is your opinion?
 
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  • #2
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 ...
 
  • #3
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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  • #4
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.
 
  • #5
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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  • #6
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.
 
  • #7
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.
 
  • #8
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.
 
  • #9
MachPrincipe said:
The bad wording of the question is intentional.
That is not acceptable.

Thread closed.
 

FAQ: Is the relativity of simultaneity the reason for time dilation?

1. What is the concept of relativity of simultaneity?

The relativity of simultaneity is a fundamental principle of Einstein's theory of relativity, which states that the concept of "simultaneity" is relative and depends on the observer's frame of reference. In other words, what is considered simultaneous for one observer may not be simultaneous for another observer moving at a different velocity.

2. How does the relativity of simultaneity relate to time dilation?

The relativity of simultaneity is one of the key factors that leads to time dilation. As time is relative and depends on the observer's frame of reference, an observer in relative motion will experience time passing at a different rate than an observer at rest. This is known as time dilation.

3. Can you provide an example of how the relativity of simultaneity affects time dilation?

Imagine two spaceships, A and B, moving in opposite directions at high speeds. From the perspective of an observer on spaceship A, time on spaceship B would appear to be passing slower due to the relativity of simultaneity. Similarly, from the perspective of an observer on spaceship B, time on spaceship A would appear to be passing slower. This is known as the twin paradox, where one twin ages slower than the other due to differences in their relative velocities.

4. Is the relativity of simultaneity the only factor contributing to time dilation?

No, the relativity of simultaneity is one of the factors that contribute to time dilation, but there are other factors such as gravitational time dilation, which occurs due to the influence of gravity on the passage of time. Additionally, the relative velocity between two observers is also a contributing factor to time dilation.

5. How does the relativity of simultaneity and time dilation impact our understanding of time?

The concept of relativity of simultaneity and time dilation challenges our traditional understanding of time as a universal constant. It shows that time is relative and can be affected by different factors such as velocity and gravity. This has significant implications for our understanding of the universe and how we measure the passage of time.

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