# Nature of Time Dilation and Length Contraction

Discussion in 'Physics & Math' started by Prosoothus, Apr 4, 2006.

1. ### DaleSpamTANSTAAFLRegistered Senior Member

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Excellent. I applaud you for trying to find out how things really work. However, you will never find out how things really work if you insist on closing your eyes to reality in favor of your preconcieved notions. This is what you do each time you insist that time doesn't dilate when the best experimental evidence is that it does. Personally, I did "explore other possibilities" for about 7 years, but since I kept an honestly inquisitive and open mind I was eventually forced to conclude that SR matched the available evidence and each of my several alternative theories did not.

What's wrong with it is that it is a very useful variable for describing how the world works. In many equations that correctly describe reality there is a term d/dt. In other words, the measurable values change with respect to some quantity. That quantity is time.

Regarding your dynamic aether, I don't see why not. Personally your use of the name "aether" doesn't bother me a bit. You just have to flesh out what you mean. So far everything you have described sounds like spacetime by another name. What you need to do is to describe your aether, how it leads to the results of current observation, and how it predicts different results for experiments that have not yet been performed. Science is perfectly willing to discard a good model for a better model, but not to discard a good model for nothing.

The reason why is simple. No aether model which matches observation has yet been proposed. If someone comes up with an aether model that actually works then it will be given the same treatment as any new theory. Specifically, if it matches all current observation and predicts new observations that are different from current theories then it will be tested and reality will be the judge.

And what would these actions and reactions unfold through if not time? What does "actions and reactions" even mean without time? Do you really think you could even describe basic classical physics in terms of "actions and reactions" without using time?

What a ridiculous quote. All of the things you mention are the things that modern physics (the relativists as you say) are looking into.

-Dale

3. ### DaleSpamTANSTAAFLRegistered Senior Member

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When I think of time I think of the thing that quantities change with respect to. In other words time is the t in the d/dt terms that crop up all over physics.

The absurdity I intended to point out is the idea that talking about a non-dilating "true" time has any physical significance.

Again, Occam's razor is a big argument in favor of SR. It is hard to beat a theory that makes so many correct predictions with only 2 simple postulates.

-Dale

5. ### DaleSpamTANSTAAFLRegistered Senior Member

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I don't know exactly what you mean by "predisposed". Regarding momentum in SR I would look at the Wikipedia article on Four Momentum. The four-momentum is the relativistic equivalent of regular momentum. The components of the four-momentum are the energy and the regular three-momentum, and the magnitude of the four-momentum is the mass which is frame-invariant. The nice thing about the four-momentum is that it is conserved and so in one relativistic conservation principle you get the classical conservation of momentum, energy, and mass.

-Dale

7. ### PeteIt's not rocket surgeryRegistered Senior Member

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Interestingly, I think this could be a valid paradigm that might be quite useful in some situations.

There's a great chapter in Kip Thorne's Black Holes and Time Warps (read it! everyone!) called What Is Reality, in which he discusses two equivalent paradigms of GR, one in which space-time bends, and one in which our clocks and rulers bend.

Extremely briefly (too briefly.. really, find and read it!):
In the curved spacetime paradigm of GR, Perfect clocks and Perfect rulers accurately measure spacetime, which is curved by mass-energy.
In the flat spacetime paradigm of GR, spacetime is flat, but Perfect clocks and Perfect rulers are rubbery, their shapes and readings altered by gravitational fields. They don't always accurately measure spacetime.

Quotes:
"What is the real, genuine truth? Is spacetime really flat, or is it really curved? To a physicist like [Kip Thorne] this is an uninteresting question because it has no physical consequences. Both viewpoints give precisely the same predictions for any measurements performed with any kind of physical apparatus whatsoever... Moreover, physicists can and do use the two viewpoints interchangeably when trying to deduce the predictions of general relativity."

"This freedom carries power. That is why physicists were not content with Einstein's cured spacetime paradigm, and have developed the flat spacetime paradigm as a supplement to it."​

I don't pretend to understand this fully... so if you want to know more about it, I'll just point you to the book.

8. ### PeteIt's not rocket surgeryRegistered Senior Member

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Confession - most of that last post was a cut'n'paste from a post I made a year ago.

9. ### DaleSpamTANSTAAFLRegistered Senior Member

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Hey Pete,

I agree with Kip, it is a completely uninteresting question. But I will admit it here and now: if any of the dilating-clocks-and-non-dilating-time crowd can show any use for the concept then I will shamelessly use it whenever appropriate. What problems does it simplify, but still produce the correct answer? What situation does it conceptually clarify? Show that and I will embrace the idea. Until then, however, I will continue to attack the concept as the completely useless and physically irrelevant nattering typical of the anti-relativity crowd.

-Dale

10. ### CANGASRegistered Senior Member

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1,612
"nattering".

Wow! That takes me back to thrilling days of yesteryear when the President's chief lackey and boot licker vehemently disparaged anyone as a "nattering nabob" when they wildly and baselessly claimed that Nixon was a crook.

Thanks for sending me back so many decades in your literary time machine to a time when I was already intensely studying Relativy ( and antirelativy ) and sometimes paid a little attention to politics and current news.

Last edited: Apr 11, 2006
11. ### dav57Extraordinary Thinker ThingyRegistered Senior Member

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Dalespam,

Please consider a row of dominoes placed ready to fall. There are 1000 dominoes which you have set up before I come along and push the first one. A single action takes place and a process begins followed by a set of events which unfold. The result is purely physical and we draw conclusions from what we have seen.

Please explain to me how time is a requirement for this process. The way I see it, the requirements are mass, position, gravity and an initial force on the first domino. Time is NOT required for this to happen. Time is only useful when comparing one set of physical processes against another.

Please explain how time is a requirement here???

12. ### CANGASRegistered Senior Member

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Even though I cannot pass for Dale, I will interject to comment that you could not have typed the second and then the third "?" unless your typing happened in a sequence of events which, in my opinion, pass for TIME.

13. ### przyksquishyValued Senior Member

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3,171
Interjection #2: If you were told to write a 24 volume encyclopaedia by dawn tomorrow, get to the other side of the planet in 3 minutes, or make sure all the dominoes fell in under a nanosecond, what would you ask for more of?

14. ### dav57Extraordinary Thinker ThingyRegistered Senior Member

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No. Time assists you to measure and compare what has already happened or predict when an event will take place in comparison with other events.

Time was NOT required for me to press ???. Only a sequence of complex processes one after the other.

15. ### RaphaelRegistered Senior Member

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A construct used to standardize periods of change?

16. ### dav57Extraordinary Thinker ThingyRegistered Senior Member

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If you wanted the dominoes to fall in under a nanosecond you require more force, or for the dominoes to be closer, or smaller, or perhaps do the experiment in the vicinity of a larger gravitational field. Why is time necessary? All you need do is find a way of making the whole process take place "quicker" relative to your clock! Why don't you get this?

17. ### DaleSpamTANSTAAFLRegistered Senior Member

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Sure. Roughly speaking you push one of the dominoes exerting a force (f=dp/dt) which then accelerates (a=dv/dt) the domino which gains some velocity (v=dx/dt) and gains some energy (E=.5m(dx/dt)^2) which is then transfered to the next domino by the same procedure. Lots of d/dt terms all over the place.

Seems to me that time is pretty important to the situation. Besides, time is implicit in your comments of "initial force", "first domino", "process begins", "set up before", etc.

-Dale

18. ### DaleSpamTANSTAAFLRegistered Senior Member

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Thanks for noticing! I try to use fun words when I have the time.

What is a nabob? Maybe I can throw that in next time.

-Dale

19. ### DaleSpamTANSTAAFLRegistered Senior Member

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I cannot pass for CANGAS either, but I will point out that the concept of time is implicit here in the words "sequence", "process", and "after".

-Dale

20. ### DaleSpamTANSTAAFLRegistered Senior Member

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Sure, or "rates of change" for non-periodic changes. In other words, if something is changing what is it changing with respect to or changing over?

-Dale

21. ### dav57Extraordinary Thinker ThingyRegistered Senior Member

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It appears you are more concerned about defending and protecting the equations again.

I don't see why an event requires time. Think about it. All it requires is a cause and effect. One process causes another process and so on. The amount of "time" it takes is nothing more than a comparison of one set of processes to another. What's your problem with accepting that. Accepting this doesn't compromise anything with respect to relativity.

22. ### Physics MonkeySnow Monkey and PhysicistRegistered Senior Member

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Hi dav,

Why all the insults, dav?

Anyways, I would suggest that you have yet to formulate any of your questions without using the concept of time. For example, what meaning has "cause and effect" without the notion of before and after? I would be curious to hear you explain the statement "one process causes another" without using the concept of time. It seems to me that you are using a notion of primitive causality (which is still a notion of time) while trying to emphasize the role of physical processes in actually giving a measure to time.

Last edited: Apr 11, 2006
23. ### dav57Extraordinary Thinker ThingyRegistered Senior Member

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What insults? I wasn't aware of any intended insults