Understanding Time Dilation: How Fast Do You Have to Go?

[DrGreg]

I became a non-believer after reading a lot about SR, not as a matter of faith. The reason for my taking part here was to test my belief. So far all your arguments have not persuded me to change my stand.

Logically there are 3 views of time dilation you can take:

1. You can take the positive view that it is true
2. You can take the negative view that it is false
3. You can take the neutral view that it might be true or false

The logic of my argument in this thread has been to show that if you begin with the neutral view, the demonstration should convince you, by the end, to take the positive view.

However, if you begin by taking the negative view, then, frankly, nothing is going to change your mind. Yes, you will find contradictions, but the contradictions are not between the parts of my argument. The contradictions are between my argument and your assumptions.

If time dilation is true, it must mean that clocks that were once synchronised do not remain synchronised. Your attacks on my argument rely (whether you realize it or not) on an implicit assumption that clocks do remain synchronised.

As this argument has been going round in circles for a long time, I see no point in continuing along this road. I think it would be good for you to follow the advice in post 175 and look at this from another angle.

As for GPS, I just searched this forum for “GPS dilation” and found https://www.physicsforums.com/showthread.php?t=87010", for example, and many more. I’m sure other readers may be able to quote better references.

For a whole list of various experimental evidence look at this thread: Experimental support for SR & GR.

 

[EngineeredVision]

Potential Solution

I first want to apologize that I have not yet read all the posts throughout this thread. However, I believe that I may be able to provide a way to add a visualized approach to this subject. Until just today, I myself was having difficulty entirely grasping relativity, especially SR and how simultaneity and time dilation occured.

Being a technical artist and animator with access to advanced 3d modeling and animation programs I decided to create some visual simulations that would help illustrate how simultaneity and time dilation operate. I've had many intelligent individuals attempt to explain how SR works in the past, yet never fully understood it. Words and even mathematical expressions and equations aren't enough sometimes. A picture is worth a thousand words, and an animaiton is worth even more. Upon viewing the animations that I created the relationships jumped out at me eliminating my previous doubts about the concepts of relativity.

Anyway, if members here believed that there would be enough of a use for animations such as these then I might be willing to improve them and make them presentable in a pre-rendered avi or mov format. Unfortunately, I'm currently without webspace so I don't have anywhere where I could upload the animations, but if there is a significant demand for these type of visual tools/simulations then I'll try to make something happen.

Sometimes, seeing really is believing.

 

[russ_watters]

Okay, I am really sorry for all the mess. Please forgive me as you would do some other slow students. As to the GPS, I do not know a lot. It seemed there is plenty of information available on the internet. Just tell me how time dilation is applied to GPS because I have not found any (on the internet) to this effect.

Then you must not have looked, because there is tons of material out there (some already linked). The gist of it is that the clocks on GPS satellites are adjusted prior to launch to run at a different rate than identical clocks on earth. After launch, they stay in sync with clocks on the ground, to within a very high degree of precision.

I wish to point out, my reading of other dissident scientists showed, experiments (GPS included) claimed to be verifying the time dilation idea could be interpreted in different ways. In order to silence dissent, you should be able to show, time dilation is the only mechanism to make GPS work well, no other.

This absurd request highlights that you really do have a strong faith-based belief that time dilation isn't real. Unless you start taking an honest and open-minded view of the subject, you will never understand it.

Sam, try this on: using the assumption that you are wrong, prove to us that you are right!

 

[Sam Woole]

As this argument has been going round in circles for a long time, I see no point in continuing along this road. I think it would be good for you to follow the advice in post 175 and look at this from another angle.
As for GPS, I just searched this forum for “GPS dilation” and found https://www.physicsforums.com/showthread.php?t=87010", for example, and many more. I’m sure other readers may be able to quote better references.
For a whole list of various experimental evidence look at this thread: Experimental support for SR & GR.

Thank you DrGreg for the links to the GPS and other evidence material. I shall take a good look at them and see whether I can be convinced. Regardless whatever may be the outcome, my scope of view will no doubt become wider.

My thanks also go to everybody else who have taken part in this thread such as Doc Al, JesseM and russ-waters, etc.

Wishing to see you again after I have digest all the material.

Sam.

 

[jackle]

...if members here believed that there would be enough of a use for animations such as these then I might be willing to improve them and make them presentable in a pre-rendered avi or mov format...

I'd be very interested to view your work. Unfortunately, I don't have any free time to contribute to your project.

 

[FX89]

I don't know how you got that conclusion from my words. What I said was: "The two twins don't disagree about what the other twin's clock reads--the traveling twin agrees that 3.944 years have passed on the earth-twin's clock, and the earth-twin agrees that 1 year has passed on the traveling twin's clock." So if they departed at the age of n, this sentence tells you that the traveling twin would agree that the earth-twin was n+3.944, and the earth-twin would agree that the traveling twin was n+1.

I can see this post is more than an year old and probably abandoned, but if by any chance the people that were posting here managed to travel forth through time and see this reply, i was wondering:

1) why do they have to be tweens?

2) (more serious mather) can anyone explain why this phenomena is occurring? Or is it just measured in clock ticks?


I'd be greateful to anyone who answered this post. (preferable during this lifetime as i don't yet understand what makes time travel possible)

 

[pervect]

How about starting a new thread with a self-contained question? This thread is too long (and too argumentative) for me to want to wade through it - at least that's my opinion.

 

[owenhbrown]

I have a problem more related to GR.

I read that if you have a stop-watch on the ground and another on a very high tower the one at the top, from the perspective of an observer on the ground, would move slower.

I can deal with that.

But then I read, I think, that if the stopwatch was brought down from the tower the two stop-watches would be in unision, reading the same time...

Now did I read this wrong? That just doesn't make sense to me... Is this example true?

I would imagine that the stop-watch on the tower, when brought back to Earth, should be BEHIND the time of the stop-watch at the bottom.

Please clarify...

 

[Ich]

I read that if you have a stop-watch on the ground and another on a very high tower the one at the top, from the perspective of an observer on the ground, would move slower.

It would tick faster.

But then I read, I think, that if the stopwatch was brought down from the tower the two stop-watches would be in unision, reading the same time...

Now did I read this wrong?

You probably read this wrong.

I would imagine that the stop-watch on the tower, when brought back to Earth, should be BEHIND the time of the stop-watch at the bottom.

Yes, but it would be ahead, not behind.

 

[owenhbrown]

Ok thanks... that all makes sense to me... Now I feel like reading more =)

 

[bydavies]

With all the material I have read about time dialatiion, I have learned that the only effect is the illusion the observer sees and there is no physical time difference once the object traveling and the observer are brought together.

There's a nice demonstration here http://uk.youtube.com/watch?v=KHjpBjgIMVk, which explains the theory in ways that even I could understand.

 

[Doc Al]

With all the material I have read about time dialatiion, I have learned that the only effect is the illusion the observer sees and there is no physical time difference once the object traveling and the observer are brought together.

Read up on the "Twin Paradox"; the time difference when the twins reunite is quite real.

There's a nice demonstration here http://uk.youtube.com/watch?v=KHjpBjgIMVk, which explains the theory in ways that even I could understand.

That's just an illustration of time dilation. Note that the ship and the Earth observers never get to reunite and compare clocks.

 

[owenhbrown]

You see what I mean now? ByDavies brought up the exact point that made me want to never try to understand time dilation - the suggestion that the clock moving faster at the top of the tower is only an illusion and no difference would be observable when the clocks are brought together again.

How does the act of bringing the clock back to Earth suddenly make the time go back to normal, Earth time?

 

[JesseM]

You see what I mean now? ByDavies brought up the exact point that made me want to never try to understand time dilation - the suggestion that the clock moving faster at the top of the tower is only an illusion and no difference would be observable when the clocks are brought together again.

But as pervect pointed out, bydavies was wrong--"the time difference when the twins reunite is quite real."