Let's assume you have three clocks sitting next to each other. They are relatively stationairy and they're synchronized. Let's call these clocks A, B, and C.

Suddenly, clocks A and C both fly away from clock B at a speed of .45c, while clock B remains stationairy. Clock A and C are both flying in opposite directions of each other. After 1 second of clock B, clocks A and C turn around and fly back towards clock B at the same speed of .45c. When clocks A, B, and C are together again:

A) What time do each of the clocks indicate if when they started flying apart they were all synchronized to read 0.00 seconds?

B) Are clocks A and C synchronized at all times, or not?

Tom

The two clocks would be synchronized and read a slower time than clock B. During the flight, each clock would be going relatively slower through time than each other. This seems contradictory, but it's only relative. As soon as they turn around they rejoin the reference frame of clock B and synchronize, then they fly to clock B and do it again.

Alpha,

This seems contradictory, but it's only relative.

It doesn't seem contradictory, it is contradictory.

How can the clocks A and C be synchronized and unsynchronized at the same time? Each clock can only give one unique reading, right?

Tom

i've got a paper here somewhere, who mentions this in a longer fashion

i'll look for it and put it here

Originally posted by Prosoothus
Alpha,
It doesn't seem contradictory, it is contradictory.

How can the clocks A and C be synchronized and unsynchronized at the same time? Each clock can only give one unique reading, right?
Tom No, you're trying to think from an absolute reference frame, which you can't do.
From A's point of view, the other clocks are running slower. Same thing from C's point of view. Each one seems slower to each other. But when they slow down to turn around, they enter the same reference frame as B and their clocks synchronize as they do. It's not really a contradiction, it just seems that way. It's hard for most people to wrap their head around relativity, but even when you do it can still trip you up.

Alpha,

But when they slow down to turn around, they enter the same reference frame as B and their clocks synchronize as they do. It's not really a contradiction, it just seems that way.

How do they synchronize? Which clock, A or C, decides to slow down or speed up to synchronize with the other?

How can one clock be slower and faster than the other at the same time? The clocks can only have one unique reading at a time.

Tom

A) What time do each of the clocks indicate if when they started flying apart they were all synchronized to read 0.00 seconds?

These results will depend on acceleration and deceleration of clocks A and C. You must also specify which frame you are referring. I presume you are always using clock B as your rest frame with all measurements derived from that frame ?

B) Are clocks A and C synchronized at all times synchronized, or not?

Relative to what ? Again, are you assuming clock B as the rest frame which all measurements are derived ?

Q,

These results will depend on acceleration and deceleration of clocks A and C. You must also specify which frame you are referring. I presume you are always using clock B as your rest frame with all measurements derived from that frame ?

Yes. And for the sake of simplicity, let's assume that there is no acceleration or decceleration.

B) "Are clocks A and C synchronized at all times, or not?"

Relative to what ? Again, are you assuming clock B as the rest frame which all measurements are derived ?

Relative to clock B. However, if clock C indicates 0.79 seconds as clock B indicates 1 second, clock C will always indicate 0.79 seconds regardless of which frame you are looking at it from. (Note: The perception of time may change based on a relative frame of reference, but the appearance of the "second hand" of the clock does not.)

Tom

Prosoothus, watch out with assuming...

... that there is no acceleration or decceleration.

otherwise, how would they ever reach .45c? :p you'll mean that the acceleration and deceleration is infinitely high, so at the one moment A and C are stationary and the very next they move at .45c

anyway, Alpha, stop falling over obvious parts of the question! :p ;) :mad: :D

I'm with the others that A and C wil both show a time that is less than B and A & C show the same time.

ps. Alpha: both A and C will be destroyed by the forces applied on the clocks. :p :D

I had a quick look at this, analysis suggests:

If the positions of A and C where shifted for the duration of 1 second away and 1 second back (to travel the distance it went originally) Then clock B is going to be at 2.00 seconds.

Theory suggests that if these clocks weren't bound by quantum entanglement rules, where gravity and mass had no effect, and there was no background energy to cause friction. Then the clocks would all say 2.00 Seconds.

Reality suggests that the friction of the universe, the fact that clocks have moving parts that during that instance of acceleration could be at any given position would suggest that clocks A and C would seem to have a time loss. (As for how much, that would need more than just a simple calculation.)

This assumption is presumed from an experiment done with two clocks and an aircraft where a few seconds was lost. But most people didn't take into account for magnetic shifts, like landplate alignment, and altitude to have effects on how the clock would react in the air.

Even a version of the EPR experiment using Mozarts 40th Symphony travelling at 4.7 times the speed of light, didn't do any more than send Mozart compressed into Picaseconds.

Perhaps if you want a true answer you might like to have a search for that experiment.

Enqrypzion,

otherwise, how would they ever reach .45c? you'll mean that the acceleration and deceleration is infinitely high, so at the one moment A and C are stationary and the very next they move at .45c

I tried to simplify the situation because otherwise it would be more complex to calculate the individual time dilations for the individual speeds from 0 km/h to .45c.

I'm with the others that A and C wil both show a time that is less than B and A & C show the same time.

I agree with you. The only problem is that relativity claims that there is no absolute frame of reference, and that all the results of relative frames of reference are correct. For example, in the clocks C's frame of reference, clock A is moving away from it at a speed of .90c. According to relativity, for C's frame of reference, clock A should be running slow (1 second for clock A should equal 2.29 seconds for clock C). However, as you and I have concluded, when you look at clocks A and B we find that they are synchronized and there is no time dilation.

By the way, let me go out on a limb: I predict that clocks A and C will not be completely synchronized, there will be a slight variance. This variance is directly proportional to the speed of clock B relative to the absolute frame of reference. In other words, the greater the speed of clock B in the absolute frame of reference, the greater the variance between clock A and C.

Tom

Stryderunknown,

From reading your post, I can see that your not a firm believer in relativity. :) I agree with you that time doesn't slow down at high speeds, only reactions do.

You suggested that this "perceived" time dilation is the result of spacial friction. I'm not sure what causes it, but I leaning towards the fact that the omnidirectional speed of light (electromagnetic radiation) is only c in the absolute frame of reference. In a moving frame of reference the speed of light would be smaller or greater than c, depending on the speed and direction of the frame and the light. Since electromagnetic radiation is used to measure time in atomic clocks, the slowing down or speeding up of the electromagnetic radiation in these clocks at high speeds can influence their measurements.

Tom

I can't find the paper, but Prosoothus, I think you are missing a part: the paradox, as I remember it, is about the relativity principle and the Lorentz equation who contradict each other.

stryder, do you have some more information on those effects on clocks?, (website, from you, etc) cause, as James R pointed out, all the parts gain kinetic energy so the explaination of Paul Marmet can't be correct.

c'est moi,

I can't find the paper, but Prosoothus, I think you are missing a part: the paradox, as I remember it, is about the relativity principle and the Lorentz equation who contradict each other.

I explained the paradox you are referring to in a private message I just sent you.

Tom

Stryder,
Even a version of the EPR experiment using Mozarts 40th Symphony travelling at 4.7 times the speed of light, didn't do any more than send Mozart compressed into Picaseconds.

Perhaps if you want a true answer you might like to have a search for that experiment.
I have no knowledge of the EPR being used for such an experiment. I thought it was only meant ot show the strange implications of Heisenberg.
Anyway: Mozart's 40th symphony at 4.7c... I must witness THAT! amazing....
To be honest it makes your story somewahat less credible to me: what value must I give to the picasecond now? (or did you mistype .47c?) Also, how does a symphony travel?

and what is "the friction of the universe"?
i would appreciate some clarifications here.

Prosoothus,
I agree with you that time doesn't slow down at high speeds, only reactions do.
Well, maybe that is the entire clue! If all reactions slow down (or speed up for that matter) in an moving frame of reverence, there is no way of telling what it the real time. What if time is defined by the progress of those reactions?

And I think we should ask an expert in what situations electromagnetic radiation does not travel at c. (I know it is possibille in principle and Feynmann has something to say about it. (I have nothing to quote here, though).

Merlijn

Prosoothus,
I'm glad you mentioned about reactions "Slowing down", as it would appear from the position of either A or C while moving that the universe was slowed, although you would find that if you look at those clocks at the same instance, they too would be as slow as the universe around it.

I mentioned spacial friction because all matter has entanglement that can have small gaps allowing radiation to pass through, at speed it's more likely to come up against more friction, as any radiation isn't likely to make it directly through the holes.

This can be proven with a simple experiment of turning a bicycle wheel infront of a torch light, the faster the wheel turns then the centre of the wheel appears solid because the spokes are passing at speed creating a blur.


C'est Moi,
I'm afraid I had no papers or URLS to quote, as at the time I was just analysing what would be the case.

What I can say is that a wave function hitting a object at speed, can change it's amplitude similar to how Horizontal and Vertical frequencies are used to tune a picture in on a television.

I suppose you could add to the experiment, a radiation bombardment that is vertical, and another that is horizontal to see what differences occured.

Merljin,
I might have mistyped the speed info, From what I remember I worked out how fast information was travelling in picaseconds.
Mozart just happened to be what got picked.

As for mentioning "Friction", the universe is filled full of energy. It swamps everything and it can cause friction (Again I mentioned Horizontal and Vertical frequencies, that could interact with the amplitude/wave functions of all quanta travelling)

Hope that's understandible.

Originally posted by Prosoothus
Alpha,



It doesn't seem contradictory, it is contradictory.

How can the clocks A and C be synchronized and unsynchronized at the same time? Each clock can only give one unique reading, right?



They are not synchronized and unsynchronized at the same time. When they are first synchronized, they are in the same frame. When one clock changes inertial frames, the two are no longer synchronized. This is not contradictory, but it is admittedly counter-intuitive, which is not the same thing. "Contradiction" ensues when multiple solutions emerge from a theory which cannot all be true. Relativity has no such contradictions. That is, when you want to determine what time which clock reads according to such-and-such a reference frame, you get a unique answer.

okay... from what alpha says he sounds right... i think? if you go start at one point and go 167658.741 miles away from your starting point (the actual distcane traveled at the speed of .45c in 2 sec.) you time will be slower than the time at your starting point because of our expanding universe... (relativity) but when you return to
your starting point your time will synchronize with the starting time. right??? it is one of those absolute/relative things.

so to answer your question...

a) clocks A,B, and C have a time of 0.02

b)yes

Tom2,

They are not synchronized and unsynchronized at the same time. When they are first synchronized, they are in the same frame. When one clock changes inertial frames, the two are no longer synchronized.

So you are saying that they are synchronized, then they are unsynchronized, and then they are synchronized again.

Interesting....Now in order for them to be unsynchronized, one clock must be slower than the other. Which clock is slower: A or C? How can one be slower when they are both moving away from clock B at .45c???

You forgot one important thing about clocks: They not only measure the present time, they record past times. If one of the clocks was truly slower than the other, time would have to speed up for it in order for it to resynchronize with the other clock. As far as I know, Einstein's time dilation formula doesn't allow time to speed up, just slow down. And if time can only slow down, a slower clock can never synchronize with a faster clock.

Tom

JimmyJames,

if you go start at one point and go 167658.741 miles away from your starting point (the actual distcane traveled at the speed of .45c in 2 sec.) you time will be slower than the time at your starting point because of our expanding universe... (relativity) but when you return to
your starting point your time will synchronize with the starting time. right???

Actually, no. Time dilation isn't dependent on the direction the clock is travelling. Therefore, the time dilation should be the same regardless of whether the clock is moving away, or towards its starting point(as long as its speed doesn't change).

Tom

Originally posted by Prosoothus
[B]Tom2,



So you are saying that they are synchronized, then they are unsynchronized, and then they are synchronized again.


Sorry, I read it wrong. I was thinking that C was the stationary clock. So, if A and C are accelerated in such a way that they are always traveling with the same speed relative to B, then they will always be synchronized as determined by frame B. This does not mean that A and C will agree that their clocks are synchronized with each other.

Tom

Tom2,

So, if A and C are accelerated in such a way that they are always traveling with the same speed relative to B, then they will always be synchronized as determined by frame B. This does not mean that A and C will agree that their clocks are synchronized with each other.

So are you saying that the clocks are truly synchronized, but the fact that clocks A an C don't see themselves as being synchronized is actually the result of an illusion?

Before you answer the question, remember that the all three clocks can have only one reading each. If the second hand of a clock is on the two second mark, it is on that same location in all frames of reference. Einstein speaks of time dilation and length contraction, but none of his formulas would imply that the physical second hand of the clock is in different locations dependent on your frame of reference. Therefore, this fact would imply that there is an absolute frame of reference, and that, at least part of the theory of relativity is flawed.

Tom

Hi Tom,

"Before you answer the question, remember that the all three clocks can have only one reading each. If the second hand of a clock is on the two second mark, it is on that same location in all frames of reference."

Eventually it will, yes. But you are forgetting that simultanity is no longer preserved when going from one observer to the other: for one frame of reference, the second hand can be on the second mark, while for another frame of reference, it is not (yet) at that moment.

Bye!

Crisp

Crisp,

But you are forgetting that simultanity is no longer preserved when going from one observer to the other: for one frame of reference, the second hand can be on the second mark, while for another frame of reference, it is not (yet) at that moment.

As I explained on another thread, the fact that one observer sees the second hand on the second mark, while the other does not yet, is not the result of relativity. It is the result of the light taking longer to reach the second observer. In other words, the observer that is farthur away "percieves" a greater delay than the closer observer. If you take this delay into consideration, you will find that the second hand is on the two second mark in all frames of reference at the same time.

Tom

<i>As I explained on another thread, the fact that one observer sees the second hand on the second mark, while the other does not yet, is not the result of relativity. It is the result of the light taking longer to reach the second observer. In other words, the observer that is farthur away "percieves" a greater delay than the closer observer. If you take this delay into consideration, you will find that the second hand is on the two second mark in all frames of reference at the same time. </i>

I explained to you before why your explanation is incorrect. Have you forgotten, or didn't you understand?

James R,

I explained to you before why your explanation is incorrect. Have you forgotten, or didn't you understand?

I'm sorry, James. It's just that it's so hard for me to understand things that are illogical. :)

Tom

Originally posted by Prosoothus
So are you saying that the clocks are truly synchronized,


Stop: What is "truly synchronized"? Synchronization in one frame does not imply synchronization in any other frame.


but the fact that clocks A an C don't see themselves as being synchronized is actually the result of an illusion?


No, there is no illusion, unless you want to consider all points of view an illusion.


Before you answer the question, remember that the all three clocks can have only one reading each. If the second hand of a clock is on the two second mark, it is on that same location in all frames of reference. Einstein speaks of time dilation and length contraction, but none of his formulas would imply that the physical second hand of the clock is in different locations dependent on your frame of reference. Therefore, this fact would imply that there is an absolute frame of reference, and that, at least part of the theory of relativity is flawed.


If the event of the second hand reaching the two second mark occurs in one frame, then yes, it occurs in every frame. However, there is no guarantee that it happens simultaneously in every frame. That is the thing you are missing.

Prosoothus

Before you answer the question, remember that the all three clocks can have only one reading each. If the second hand of a clock is on the two second mark, it is on that same location in all frames of reference.

You are inferring the speed of light is instantaneous. If a star goes supernova in a galaxy 10 million light years away, will we on Earth observe the event the instant it occurs? Will an observer who is halfway between us and the galaxy (5 million light years) view the event the instant it occurs?

Ok here we go again, lets try and sort this one out ... Well actually I am also making it more complicated, so you can see why it works.

The story so far... We have three frames A, B, C. From B's point of view A nd C accelerate away. And then accelerate back.

From B's view point, they do this identically with the directions reversed. From B's point of view they both return with their clocks time dilated by identical amounts (maybe see below). I.e slower than B's time.

Now A and C's point of view. In this experiment they are the same except for the direction so lets pick one say A. From A's point of view it is accelarted away from B. Can we say that B accelerated away from A ? No only in A's reference is the driver pushed into the back of the seat. I.e A is accelerated not B. A and C are not inertial frames of reference. An inertial frame of reference is S/R shorthand for an unaccelerated frame.

Ok so how about adding a fourth object D. Now this is traveling at .45c away from B, in the direction A will be accelerated.

Assume from D's point of view. B's clock is running slower than D's. From D's point of view while A is traveling along with B it is at the same slower rate as B. When A accelerates away from B, from D's point of view you might argue it is decelerating. If decelerating then A's clock stops being slowed, i.e speeds up. If we keep going it then it accelearates away from D and rejoins B. Sound like D should return with a time more than B'S ?

The reason this does not work is the key question is A acelerating D's point of view or accelerating from B's point of view ? Popular views on S/R say both, causes confusion, and is wrong. To show why consider we have two clocks on D and B based on vibrations of hydrogen. Now we have both send signals to each other 1 second long. Both frames will agree that one of the two is longer than the other. One of the two will have a slower clock.

To explain this consdier how the situation might arise. B and D are traveling together and their clocks agree. Now change it so they are moving apart at .45c. If D is accelarated relative to B, D's clock slows down. If B is accelerated relative to D B's clock slows down.

So to return to D's point of view. We have two scenarios. If we measure B's time from D's point of view we might find time is slower on D so when A starts out it is acclerated and time slows for A and all is as it was from B's point of view.

Ok take the opposite view Time is faster on D. When A returns it will have a clock that appears to have run faster. To solve this we need to return to B's point of view. Because in this situation, we can show that B has already been accelerated. So from B's point of view when A gets up to speed and moves away it is DEcelerating, and the clock on A will speed up. While C is accelearting and will slow down.

I could go on and give a description of C from D's point of view. The point is that S/R works consistantly when looked at from an inertial frame of reference. If your point of view has two or more different velocities compared to something else at different measuring times you need to be sure the frame ypou are calculating from is not the one being accelerated.

If I describe, the alternate situation of A,B and C and have B accelerate away from A to .45c and C away from A to .90c. I have described a different stituation. In this one B and C experience acceleration, in the previous experiment A and C experieince acceleration. And the results of these two different experiments are different.

Bright sparks that are following the above will be asking. How does an object know it is accelerating or has been accelerated ? Doesn't that mean there is a kind of zero frame that we can measure acceleration against ? The answer is yes. But note there is no zero speed, only a kind of zero acceleration. To make matters worse the zero acceleration is local, if separated by time or distance, observers may not agree on the zero of acceleration. (mind bending ain't it?).

The full answer to the accelaration zero requires G/R and the concept of space/time and curvature so go study G/R ! To give a hint: The accelaration is (kind of) against the space/time curve defined by gravity.

Prosoothus...
Now i am really lost.
Are you saying that the time shouldn't change?

I take back the statement I said about it resyncronizing when returning to the starting point. A and C should read a slower time than B.
I think. Explain...?

Sorry for getting in your "over my head" discussion... but I don't understand what you mean Crisp?

"Before you answer the question, remember that the all three clocks can have only one reading each. If the second hand of a clock is on the two second mark, it is on that same location in all frames of reference."

Are you saying that no two clocks can have the same time if they are in different locations? I am so lost...

JimmyJames,

I can explain to you what I really think, but my explanation differs from that of relativists. Here is what I think:

1) Clocks A and C will be almost synchronized, and both will be slower than the stationairy clock B.

2) The slight variance between clocks A and C will be the directly proportional to the absolute speed of clock B.

3) Clocks A and C will always be synchronized(minus the variance), at all times. Clock A will never be slower than C, or vice versa. If they ever where, it would be recorded by the clocks.

4)Clocks A and C will not be slower because time slows down, they will be slower because the speed of the electromagnetic radiation, that the clock is made of, changes based on the clocks speed.

The secret to making sense of all this is to seperate illusion from reality. Relativity tries to teach you that illusion is reality: That if the observer perceives something, it must be true. If you've ever been to a magic show, you know that this is not the case :).

Tom

Q,

You are inferring the speed of light is instantaneous. If a star goes supernova in a galaxy 10 million light years away, will we on Earth observe the event the instant it occurs? Will an observer who is halfway between us and the galaxy (5 million light years) view the event the instant it occurs?

No, I am saying that just because two observers see an event occuring at different times doesn't mean that the event actually occured at different times.

In the case you described, both observers are wrong. They are both observing an illusion based on the fact that the speed of light is finite. The only observer that wouldn't witness this delay-illusion is an observer that is right next to the supernova.

Tom

Prosoothus

No, I am saying that just because two observers see an event occuring at different times doesn't mean that the event actually occured at different times.

That is correct. The observers, in whatever reference frame they may view, will always see a delay due to the finite speed of light and the distance and velocity of the observers to the event.

In the case you described, both observers are wrong. They are both observing an illusion based on the fact that the speed of light is finite.

What is your definition of "illusion?" (An erroneous perception of reality.) That is not the case. The view of the observer is a delayed view of the event and is not erroneous in any way. The observer on Earth will view the same event as the observer 5 million light years closer to the event. The only difference is that they will view the event at different times due to the finite speed of light. This is not an illusion.

The only observer that wouldn't witness this delay-illusion is an observer that is right next to the supernova.

Incorrect. Although this observer is right next to the supernova, he too will witness a delay in the time between the occurrence of the event and his viewing of the event, under exactly the same conditions as any other observer, based on the finite speed of light and his distance and velocity to the event.

Of course, this observer's view of the supernova may be the last thing he ever sees. ;)

Q,

What is your definition of "illusion?" (An erroneous perception of reality.) That is not the case. The view of the observer is a delayed view of the event and is not erroneous in any way.

The observer is not seeing reality, he is seeing a reality that existed 5 million years ago. Even though there is no spacial illusion, there is a time illusion.

If you wan't to get picky about it, I agree that the observer next to the star experiences a delay as well. :)

Tom

prosoothus

The observer is not seeing reality, he is seeing a reality that existed 5 million years ago.

Good, we agree he is viewing a reality and not an illusion. If an amount of matter blown off by the supernova were to travel towards the observer and the observer was struck by the matter, would this be an illusion or a reality ? What would be the difference between this amount of matter striking the observer and the photons emitted by the supernova striking the observer ?

Even though there is no spacial illusion, there is a time illusion.

Not an illusion, just a delay, a similar delay the blown off matter would undergo traveling towards the observer.

If you wan't to get picky about it, I agree that the observer next to the star experiences a delay as well.

We gotta make sure our facts are straight, right ? ;)

If you believe that the time delay caused by the finite speed of light means that you're seeing an illusion instead of reality, then you must accept that <b>everything</b> you see is an illusion, since light takes a finite amount of time to travel any distance. The computer screen in front of you is an illusion, by that definition, since light from it takes a couple of nanoseconds to reach your eyes. You don't see your screen as it <b>is</b>, but rather as it <b>was</b> a few nanoseconds ago.

I'd argue that this doesn't make the screen any less real.