# Is time universal? NO (and its proof)

Discussion in 'Physics & Math' started by Billy T, Aug 12, 2005.

1. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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Assume a train is moving past a line of men who are standing extremely close to the passing train. Assume two small bombs have been placed on the outside of the train and they just graze the noses of the men standing along the track as they pass. The bombs will explode when light from a flash bulb, placed on the train’s side, equally distant between the bombs, reaches them. An observer on the train standing midway between the bombs observes simultaneous explosions shortly after setting off the flash bulb.

Two of the thousands of men, who were standing on the ground right next to each other and right next to the passing train are killed by the exploding bombs. The man near the end of the train dies before the one near the front. They do not die simultaneously because in the line of men’s reference frame, the light flash moving towards the rear of the train explodes its bomb before the bomb at the front of the train explodes. (During the transit of the light towards the bombs, the bomb at the rear of the train has been moving towards the on coming light, while the one at the front of the train was trying to race away from the on coming flash of light.)

Note that their “non-simultaneous deaths” is not due to the time for light to travel to any observer - I had the two (now dead) stationary observers stand right next to the bombs when they exploded. If a third stationary observer, is standing mid way between the two that get killed, that third observer would observer them die at different times. (The two delays for him to see them die, due to finite speed of light, are equal.)

CONCLUSION: Simultaneous event in one frame are not simultaneous in one moving wrt to it. This is real effect of SRT. It is not due to any delay of light traveling to an “observer” waiting to sees the events.

People who dispute SRT often claim that the events are “really” simultaneous in all frames, but only “seen to be non simultaneous.” Events (or clocks) synchronous in one frame are not synchronous in a different frame and “seeing delays” are not the reason for their lack of simultaneity as most opponents of SRT claim. Thus clocks that strike noonday chimes simultaneously in one frame can not strike them at the same time as synchronized clocks are striking noon day chimes in another frame. That is, synchronized clocks distributed about in one frame can not be synchronous with many in another frame which are correctly keeping time in that frame.

If the time dilation of SRT is computed and used to adjust the rate of clocks in one frame, it is possible to synchronize any pair of clocks in two different frames, but not all of them, if they are to correctly keep time in their own frame. The reason is simple. A set of clocks that are separated only by space in one frame are separated by a mixture of space and time in the other. Thus clocks at different locations can not be both synchronous with each others in the same frame (keep time correctly) and yet synchronized with all synchronous clocks in another frame. Take your pick, (but only one of the following two):

(1)You can have all clocks in two different frames all show the same time (Each has a unique SRT correction to it rate, which depends on the clock‘s location.) but they do not show the same time as clocks that are synchronous in their own frame. (I.e. they are not keeping correct time in their own frame.) OR
(2) You can have all clocks in both of two different frames synchronized with others in their same frame, (Keeping correct time in their own frame.) but the clocks in one frame will not be synchronous with the clocks in the other frame.

Any comments from people who claim that all clocks in two different frames can both keep time correctly in their own frame and yet be synchronized with clocks in another frame that are all also showing the correct time in their frame? I.e. people who think time is universal for all frames and thus SRT must be wrong.

3. ### MacMRegistered Senior Member

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Hello Billy T,

My only comment. I have not advocated universal time. However, I have said, and do say, that if in a common frame an event is simultaneous to two or more observers, that when viewed from other frames they appear to not be simultaneous, that that is merely a perception and in no manner has altered the fact of simultaneity of the events.

5. ### catoless hate, more scienceRegistered Senior Member

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what makes two things simultaneous then? if two observers disagree, then who is right? you seem (I don't mean to put words in your mouth) to imply a master reference frame (or either) in which things are reality, and all others are illusions. I disagree with that view.

7. ### Neddy BateValued Senior Member

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BillyT, I volunteer to comment, but not because I have any claims of SRT being wrong. I doubt that my comment will have any bearing on whether SRT is valid, but it does seem an appropriate response to your challenge:

It appears that you have already built a universal clock system into your thought experiment. Every time a bomb touches a nose, the nose clock ticks one increment. Enery time a nose touches a bomb, the bomb clock advances one increment. In what way could the two clock systems not be both synchronious and correct in their reference frame?

8. ### catoless hate, more scienceRegistered Senior Member

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I don't see that as a problem. each person will have a clock hit their nose, but different frames will disagree on the simultaneity of their nose/bomb collision.

9. ### MacMRegistered Senior Member

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Notice that I stated simultaneous in a common frame. In such a frame simultaneous means simultaneous. You are certainly free to not believe that but I find no cause to not believe simultaneity is achievable in a common frame.

10. ### RosnetPhilomorpherRegistered Senior Member

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Yes, it is possible in a common frame, <B>if</B> you mean <B>the same frame</B> when you say <B>common frame</B>. Duh...

Last edited: Aug 14, 2005
11. ### catoless hate, more scienceRegistered Senior Member

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sorry mac, didn't see that.

12. ### MacMRegistered Senior Member

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Not sure why you see the Duh as appropriate. My point was that understqanding that one should then realise that the views of others in other frames as not being simultaneous in no manner alters the fact of simultaneity of the events.

You go from physics to perception at that point. The only physics are in the frame in which they occur all else is illusion.

13. ### RosnetPhilomorpherRegistered Senior Member

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All events are simultaneous.

Well, the are, in some frame or the other. How can you decide which frame is right?

In the example, the events are simultaneous in the <B>moving</B> (w.r.t the platorm, at least) frame. So does that mean that they're not <I>really</I> simultaneous? And it's not an illusion of motion. What happens in each frame is 'really real', in that frame. You can't determine otherwise.

Off topic (somewhat): I was just curious about what you think about Quantum Mechaincs.

14. ### MacMRegistered Senior Member

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That seems fairly obvious. If two events occur in a common (same) frame such that an observer midway between the events measures them as simultaneous then they were simultaneous.

Other observers not in the center or with relative motion has to compute simultaneity based on relative velocity, distance, etc to ascertain the simultaneity.

Restate the example of events claimed simultaneous in the moving platform scenario.

WHAT? You can't calculate relative velocity, distance and determine simultaneity? I can.

I don't.

15. ### Billy TUse Sugar Cane Alcohol car FuelValued Senior Member

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I don't think it an "illusion" when in my car (my frame) I am passed by someone in their car (their frame). By your reasoning, I am only an illusion to them.

Can you clarify a little what makes something only "illusion" when the choice of frames is arbitary? I.e. physics can be equally well described in the frame with my car at rest or in the frame with his car at rest, can it not.?

16. ### MacMRegistered Senior Member

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You are extrapolating "Illusion" to far. Of course you exist and are not an illusion. However, to claim either has any specific velocity is an illusion.

This is the error in SRT. It leads to the physically impossible (and unobserved in 100 years of relativity) condition of reciprocity which causes in theory each clock to run slower than the other.

The facts are that each may have some velocity component contributing to the total relative velocity. SRT treats the total relative velocity as being in one or the other. Since gamma is not linear that leads to error when in fact GPS shows that one should compute gamma for each component to determine the effective gamma.

If two clocks are accelerated equally, from a common inertial rest, condition in a co-moving direction. You have NO relative velocity and no systemic time dilation between them, although both mutually dilate relative to their origin point of acceleration.

Likewise if you launch the same two clocks equally but in opposite directions from a common inertial rest positon, you now have relative velocity but you will not find any systemic time dilation between them. Each are still mutually dilated relative to the origin point of their acceleration.

That is it can be seen (if you actually look) that the process of time dilation is a function of absolute velocity change due to acceleration, not just relative velocity.

That is why if you now take the same two clocks at relative rest and only accelerate one, the one accelerated will record time dilation relative to the one that did not accelerate. AND you will not record any time dilation of the clock which remained at rest relative to the one that did accelerate.

That is what actual recorded data supports. Not what SRT claims that either may be considered as at rest and the other is dilated. Only one clock has ever been recorded as being dilated. And it is the clock that has the most acceleration.

If both are accelerated but by different amounts the one that accelerated the most will be the one that shows dilation relative to the slower clock and never vice versa according to SRT. That is the facts.

Last edited: Aug 20, 2005

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18. ### MacMRegistered Senior Member

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You are not applying "Illusion" to the correct parameters. Actual relative velocity is not a factor. If it applies at all relativity also applies at everyday velocities as well. It just has negligable affect.

So an illusion is an illusion at all velocities. From my perspective there is only one issue which qualifies as a real physical property and that is time dilation.

It can be observed and has been recorded. Length contraction on the other hand has not and appears to be nothing more than an illusion created mathematically based on the illusion to an observer with an inertial velocity that he is at rest and his clock still ticks at a standard rate.

It in known that clocks in motion dilate and tick slower than the resting clock. It is not merely a case of an illusion of a moving observer but becomes recorded and can be seen in a subsequent common frame.

Recognizing that therefore it becomes obvious that you cannot claim both time dilation of a clock in motion and that distance for the clock have contracted.

If time accumulated on the clock is due to spatial contraction then the clock cannot also be dilated (don't say in his frame, dilation is physical and crosses frames to show it was dilated in comparison).

If (and it is known to be the case) clocks in motion are dilated then given a velocity and a distance it will accumulate less time and there is no room to claim that distance was foreshortened.

If you try to claim both as physical realities then you compound the affect and get an incorrect answer. It is not physics to switch physical affects at the whim of the observer. Physical is physical. Anything else is an illusion.

You certainly have the perogative to disagree. I just hope you are prepared to jusify your view.

I look forward to it.

19. ### RaphaelRegistered Senior Member

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One quick question:

Given a cesium atomic clock with a frequency of 9,192,631,770 hertz traveling at a relativistic velocity, how would using relativistic time dilation (T=&gamma;T<sub>0</sub>) mathematically differ from using a relativistic frequency contraction (f=f<sub>0</sub>/&gamma; )?

20. ### RosnetPhilomorpherRegistered Senior Member

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The latter doesn't take the doppler effect into account, I think. That is, if you're talking about actual perception, instead of reality.

21. ### RaphaelRegistered Senior Member

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Neither takes doppler effect into account. I was talking about mathematics. Unless there is a mathematical difference between an observed time being dilated and an observed frequency being contracted, the difference in reality is philosophical.

22. ### superluminalI am MalcomRValued Senior Member

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There is no difference except for what quantity you are after. Frequency is just the inverse of time.

23. ### AerRegistered Senior Member

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2,250
SL is right. There is no difference.

f = 1/t

T=γT<sub>0</sub>

1/T = 1/(γT<sub>0</sub>)

f = f<sub>0</sub>/γ