Time dilation explaination with mechanical clock instead of light clockby R Power Tags: clock, dilation, explaination, light, mechanical, time 

#1
Feb812, 12:50 PM

P: 272

This page http://en.wikipedia.org/wiki/Time_dilation clearly explains time dilation by exampling with the light clock. But how can it be explained if suppose there was a simple mechanical clock instead of light clock. So, now for moving observer there is no light (in light clock) to follow longer path and hence elongate one second but only a second hand that rotates.




#2
Feb812, 01:00 PM

Mentor
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#3
Feb812, 01:11 PM

P: 272





#4
Feb812, 01:35 PM

Mentor
P: 40,907

Time dilation explaination with mechanical clock instead of light clock
I don't think there's any simple way of deducing time dilation using mechanical clocks, if that's what you're looking for. (At least I've never seen such a demonstration.)




#5
Feb812, 02:09 PM

P: 272





#6
Feb812, 02:18 PM

PF Gold
P: 472

If you want my view, the answer is clear: the mechanical clock also suffers time dilation (as per the same pattern as the light clock) because a clock is a moving thing inside an enclosed space; the clock ticks when the moving thing bounces against the walls or otherwise changes direction. The cause for this "acceleration" is an electromagnetic interaction (light) or any another force that does its job in a manner that is analogous, at least for this purpose, to light. 



#7
Feb812, 02:26 PM

P: 272

What about my explanation in post #5?




#8
Feb812, 02:56 PM

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#9
Feb812, 07:59 PM

P: 359

I've been wondering about this as well.
If the light clock were to be replaced with say, an infinitely precise pendulum clock, how would the thought experiment be explained then? Would it be different if the thought experiment were "relocated" to deep space, using the infinitely precise pendulum clock? 



#10
Feb812, 09:22 PM

P: 198

I don't get what the problem is. Any clock measures time, so when the fabric of space is distorted, time will flow slower, and thus any clock measurement will be slower since the flow of events is slower proportionally to the gravity. Although I will admit I don't quite understand completely why the shape of a well actually makes time run slower, but we know that it does. That's why if you are in an airplane, your clock will run eversoslightly faster than clocks on the ground.




#11
Feb912, 02:15 AM

P: 503

The request for an explaination is a good one.
If you take for granted that all possible clocks will be identically time dilated, then using the light clock as your generic clock in all subsequent though experiments is fine. But all must admit that light is a very special entity with extraordinary properties, and if you are attempting to verify the universality of clock dilation in your own thinking before moving to just take it for granted, it makes sense to wonder what would be the effect on the actions of a mechanical clock  something with size and mass. It makes sense to wonder that different orientations of the oscillating and rotating parts of the clock might change their lengths and radii in one dimension, and therefore effect centers of mass, centers of rotation, and thereby effect linear and angular accelerations, etc. This is not just "physical processes slowing down"... there are gross mechanical effects to account for, as well as smaller things in chemistry like molecular bonds, orbitals, and even smaller things, etc. Surely someone has done this analysis and demonstrated that all these effects must balance out so that the mechanical clock may be replaced with the simple light clock without reservation? 



#12
Feb912, 02:26 AM

P: 3,178





#13
Feb912, 02:30 AM

P: 3,178





#14
Feb912, 03:43 AM

P: 272

In case of light clock even, when observer travels at some speed, path of photon appears elongated to the moving observer now the velocity of observer should have been added to velocity of light which we know is not possible so the overall velocity of photon for the observer is constant i.e c (which causes dilation) but does this mean that photon has to slow its speed down in order to maintain total speed(photon speed + speed of observer) equal to speed of light?




#15
Feb912, 04:29 AM

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#16
Feb912, 04:37 AM

P: 272

When clock at rest... speed of photon = c speed of photon to observer = c When clock moves... speed of clock = v speed of photon = c speed of photon to observer= c+v but that is not possible..... so let speed of clock = v speed of photon = cv speed of photon to observer = cv+v = c. 



#17
Feb912, 04:54 AM

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#18
Feb912, 05:07 AM

P: 1,235

Manmade mechanical clocks might not be well suited for this analysis.
After all, it is almost impossible practically to test time dilation with such clocks. I see two "mechanical" alternatives: 1) atomic clocks that are based on a (quantum) mechanical system, indeed 2) astronomical bodies Given that several astronomical observations support special relativity, it is very likely that time dilation could be explained by taking an astronomical system as an example. This would amount to comparing astronomical observations made in differents frame of references. I was impressed by a paper from Julian Barbour on the nature of time: http://platonia.com/nature_of_time_essay.pdf Starting from this point of view would not only offer you some insight about how to answer your question, but it would also invite you to reflect about your question itself. 


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