The Twins Paradox and the Experience of Time

[CJames]

Hello again LWS,

“. . . time is altered by acceleration or gravity. But again, it is always the time of the other reference frame that is altered.” Now if that were true, then doesn’t that create a preferred frame of reference?

No. I don't want to speak for Janus, since you were asking him, but I will respond to this part. It is not creating a preferred reference frame, because this same concept applies to all reference frames.

Janus answered, “. . . Consciousness has no unique sense of time of its own; That its sense of time is derived from its physical surroundings.” Of course, that is what I’m asking, and there is his opinion. My opinion is that consciousness might sense it in spite of all measurements appearing normal

But is it truly his opinion, or is it fact? The way I see it, there are two possibilities for a concept. It can be tangible, or intangible. A spirit or consciousness that has no material actions governing it is intangible, since it can not be measured. Time and space, on the other hand, are measureable concepts, and are thus tangible. For this reason, it seems to me, the concept of time does not apply to an intangible conciousness. That's the quick and dirty anyway.

 

[Janus]

Originally posted by LW Sleeth
CJames & Janus,



Janus, I don’t know if you agree with CJames when he says the person who is measuring is at rest, and adds “. . . time is altered by acceleration or gravity. But again, it is always the time of the other reference frame that is altered.” Now if that were true, then doesn’t that create a preferred frame of reference? Is my point correct that the reason for assuming the measuring position is at rest is for purposes of measurement and calculation alone? It’s not that one position is any more at rest (or moving) than another.



No one disputes that each twin ages differently while one travels, right? No one disputes that the rate of time is determined by one’s frame of reference. Do we agree that when we say no frame of reference is “preferred,” it means as one alters acceleration/gravity, time-space contracts/expands proportionately so that all factors always appear “normal.” Therefore (in the case of the twins paradox) the only way the traveling twin can tell if his frame of reference has been altered (from what it was while on Earth), is when he returns to the prior frame of reference and finds time there has marched along at a faster pace than his has.

The problem is, the Instant you say:

" as one alters acceleration/gravity, time-space contracts/expands proportionately so that all factors always appear “normal.” "

You are making a Tacit assumption of a preferred frame of reference. You are saying the state you were in before the "change" is the preferred frame. (You changed wrt to it, causing space and time to alter for you, you just don't notice it.) This is not what Relativity says what happens.

Let's use gravitational time dilation as an example.

Two clocks are in a tall tower, one at the base and one at the top. And this tower is in a uniform gravity field (One that does change in strenght over the height of the tower)

At the base, you look up to the clock at the top. The light carrying the info about the clock has to "fall" the Height of the tower. (It has to traverse the Difference in gravity potential.) when it does this it must gain energy. An ordianry object would just pick up energy as extra velocity, but light can't gain velocity, so it gains energy by increasing its frequency. As a result, you will see the clock run faster than yours. (this is a Doppler-like effect.)

The longer you watch the upper clock, the greater the elasped time between yours and it.

Now imagine that you are at the top of the tower. As you look down at the lower clock, now the light has to "climb up against gravity and lose energy as it does so. This loss of energy, is reflected as a lowering of frequency and causes the lower clock to appear to run slow.

Note, That which clock "runs slower" or "runs faster" merely depends on where you are standing. You can not say in any absolute way that the upper clock runs "fast" or that that Lower clock Runs "slow", only that relative to each other they run at different speeds. Also note that there is no "physical" cause that would effect each clock's time rate. (They feel exactly the same g force)

Now imagine yourself halfway up the tower. The upper clock will appear to run faster and the lower slower.

The clocks are on open elevators so that you can see them at all times. You push the buttons so that each clock comes to your level , watching them as they climb or descend. As they do so, you will note that their rates will start to match your own, But the accumulated time difference between them and your clock will remain. Once they become even with you they will click at the same rate as yours, but will show different times. One will have shown more time as having passed, and the other less. Remember, at all times both clocks were an equal g field so you cannot attribute the difference in their time to the local conditions they were in.
So even though the apparent difference is time rates was due to the light traversing the height between the clocks, the resulting time difference is "real". And you cannot say that one clock ran fast and just didn't notice it, or that the other ran slow and just didn't notice it.

The same is true for the twin paradox, you cannot say that one twin's time rate ran slow and he just didn't notice it. In fact, during the Twin paradox, the twins won't even agree as what their relative rates of time are at any given moment, only what the total elasped time for each is at the end.

 

[Fliption]

Originally posted by Janus
The problem is, the Instant you say:

Let's use gravitational time dilation as an example.

Well, I'm going to admit it. I don't get it. Lol. I've been reading about this theory for years and I've heard all these explanations over and over.

In this example, it just doesn't make sense to me that neither clock "changes" it's rate, yet somehow when they are brought together they have a "real" difference. I always think I understand until the end when the differences turn out to be real.

If I ever figure this thing out, I swear I'm going to come up with a way to explain it.

 

[Les Sleeth]

Originally posted by Janus
You are making a Tacit assumption of a preferred frame of reference. You are saying the state you were in before the "change" is the preferred frame. (You changed wrt to it, causing space and time to alter for you, you just don't notice it.) This is not what Relativity says what happens. . . . Note, That which clock "runs slower" or "runs faster" merely depends on where you are standing. You can not say in any absolute way that the upper clock runs "fast" or that that Lower clock Runs "slow", only that relative to each other they run at different speeds. Also note that there is no "physical" cause that would effect each clock's time rate. (They feel exactly the same g force)

Actually, gravity is not the same for both clocks; it is stronger for the clock closer to the ground than the clock situated higher above it. This is why I am saying there are two physical issues involved, one is measurement and the other is rate of entropy or aging. If when the two clocks were brought together one hadn't moved faster than the other, then we'd know it had only been a measurement issue. But the fact that the hands moved further on one clock than the other, and movement demands entropy, we also know the rate of entropy was different in each frame of reference.

You claim I create a preferred frame of reference by comparing the traveling rate of time to Earth's rate of time saying, "You are saying the state you were in before the "change" is the preferred frame" but I don't yet see how that is true.

What I said was that traveling time for the twin involving acceleration is objectively "different" from the time of the earthbound twin. The reason I, as an objective observer, can know that is because I can observe both twins, just like the clocks, and watch them age at different rates. As the traveling twin steps off his space ship, he and his brother have actually aged differently -- I can see it and they can see it, plus the clocks agree they have. Yet as the traveling twin measured time (or anything else) while traveling he found no indications that would tell him when he returned his brother would be 35 years older than him.

Of course, I've introduced a third issue (other than measurement and aging), which is that of consciousness. My point was that before the traveling twin took off he'd lived for thirty years at Earth's rate of time. In physics that does not mean it can be considered the preferred frame of reference, but it might serve as an experiential reference point if consciousness is not fundamentally physical. If so, then we might expect the non-material aspect of consciousness to "notice" something experientially different about time when its rate significantly changes.

 

[ahrkron]

Hi, it's been a while since you addressed my post, but replying seems to be relevant at this point.

Originally posted by LW Sleeth
I probalby should have made it more clear that I've assumed the twins grew up together,

I was assuming that as well. All physical processes will have "business as usual" on each frame. This includes all brain processes.

Now, even if you assume that thought (or "experience") is not an exclusive result of material processes, you have to agree that there is a close connection between both. Let's say, for the sake of argument, that there is a soul in communication with the brain.

Such soul would learn to estimate/use time using some brain processes (let's say, some stable cycles of activity in some strucutres), and to pace itself according to the time it takes for the brain to transform a "soul-thought" into an electrochemical pattern in the language centers of the brain (or the image-processing centers, depending on how your thought-processes are). This is not only in order to express itself, but also in order to "acquire" some information stored in the brain, to be used as part of its reasoning (or "experiencing", or whatever the soul does).

Some issues soon arise:

1. If the soul is to notice the change in the "pace of time", it needs to have another way of estimating time, which has to be non-physical in order to be unaffected by relativity. What would this be?

2. Such "soul-time" can be diferent for different souls, or the same for all. If different, what sets its pace?, if the same, then there is a preferred physical reference frame after all (the one whose "time pace" coincides with that of all souls)... plus a huge conspiracy that makes the universe look like if such was not the case (why would there be a special physical frame, and yet all physical laws be consistent with no such a thing?).

3. The strong correlation between brain processes and "soul-experiences" (which we are assuming to be non-causal) put strong constraints on what such experiences can be. Let's say that, after living 30 years on Earth, you start a trip at a speed that corresponds to a time dilation of 1000. Your soul, used to "Earth speed", would have the potential to "experience" 1000 more experiences than before the start of the trip. However, those experiences can be, at most, very peculiar:

__a. They cannot be perceptions (of what is happening on the ship, let's say) since all perceptual information is happening at "physical-time-rate" (both the signals themselves and the neural processes that make them available for the soul are "affected by relativity").
__b. They cannot be "inside talk", since all language-related resources and processes are also at "physical-rate". The same goes for "image-like-thoughts".
__c. They cannot use any information stored in the brain,
__d. Those experiences would not leave the usual imprint on the brain; i.e., you would keep no recollection of them... unless souls were able to keep memories without the help of a brain, and yours decided to wait until appropriate in order to record such experiences on the slow functioning physical brain it now has to deal with (but then... why would we have brains, if souls were able to memorize, reason and decide).

4. Also, the very definition of time comes into play. Is time that which is measured by clocks, or that which has to do with the souls' rate for "experiencing" word-less, image-less, usually unremembered sensations?Even assuming the existence of souls, I think it is much more plausible that time is what clocks measure, that souls can only use physical processes to estimate time or experience experiences, and that no preferred frame exists.

 

[Janus]

Originally posted by LW Sleeth
Actually, gravity is not the same for both clocks; it is stronger for the clock closer to the ground than the clock situated higher above it. This is why I am saying there are two physical issues involved, one is measurement and the other is rate of entropy or aging.

I specifically stated as a condition that the tower was in uniform gravity field. So for this experiment there is no difference in the strength of the gravity from top to bottom and no difference in the physical conditions each clock finds itself in.

 

[Les Sleeth]

Originally posted by Janus
I specifically stated as a condition that the tower was in uniform gravity field. So for this experiment there is no difference in the strength of the gravity from top to bottom and no difference in the physical conditions each clock finds itself in.

Yes, but you had gravity affecting EM energy, so the conditions were not the same for both clocks.

 

[Janus]

Originally posted by LW Sleeth
Yes, but you had gravity affecting EM energy, so the conditions were not the same for both clocks.

The gravity affected the light carrying information between the clocks. The local conditions of each clock are, however, identical.

 

[Janus]

Originally posted by LW Sleeth
[B

What I said was that traveling time for the twin involving acceleration is objectively "different" from the time of the earthbound twin. The reason I, as an objective observer, can know that is because I can observe both twins, just like the clocks, and watch them age at different rates. As the traveling twin steps off his space ship, he and his brother have actually aged differently -- I can see it and they can see it, plus the clocks agree they have. Yet as the traveling twin measured time (or anything else) while traveling he found no indications that would tell him when he returned his brother would be 35 years older than him.

[/B]

The problem with you as "an Objective observer" is that what you see depends on which frame you are watching from. If you watch from the Earth twin's frame, the space twin's aging is the one that has changed. If you watch from the Space twin's frame, It would be the Earth twin's aging that changed. From some other frame, both twin's aging changed.

If you are trying to invoke the idea of the "outside observer" (one that belongs to no frame of reference) , Relativity says no such thing exists.

If you are trying to say you are watching from some frame where you can absolutely say which twin actually underwent change of time rate, you are invoking a preferred frame of reference. Again Relativity says such doesn't exist.

 

[Les Sleeth]

Originally posted by Janus
The problem with you as "an Objective observer" is that what you see depends on which frame you are watching from. If you watch from the Earth twin's frame, the space twin's aging is the one that has changed. If you watch from the Space twin's frame, It would be the Earth twin's aging that changed. From some other frame, both twin's aging changed.

If you are trying to invoke the idea of the "outside observer" (one that belongs to no frame of reference) , Relativity says no such thing exists.

If you are trying to say you are watching from some frame where you can absolutely say which twin actually underwent change of time rate, you are invoking a preferred frame of reference. Again Relativity says such doesn't exist.

You gave me just such an "objective observer" in your clock hypothetical. There is no such possiblility as you described for a single observer, but I knew you gave it in order for us to discuss what was going on outside of an individual's perception.

And actually my little proposal about some essential part of us being unaffected by relative circumstances pretty much corresponds to the objective observer. The only reason it might remain unaffected by relativity is because it remains constant throughout.

I am not saying this constant part of consciousness which might recognize change (the "soul-thought," as Ahrkron put it, and who I've yet to answer . . . I'm still thinking how to respond) is preferred in any physical way, but rather it would be a visceral "sense" someone in touch with that part of himself might feel. So I do not believe any physical aspect of us, such as the intellect or physical senses, would be able to establish a preferred frame of reference, just as you say.

 

[Fliption]

Originally posted by Fliption
Well, I'm going to admit it. I don't get it.

OK I've been doing some reading and thinking about this. I've also gone back and read through this thread again. It seems a lot of the confusion for me is arising because there are actually 2 different discussions going on.

There is a discussion about relativity and then there is the materialism discussion. The discussion on relativity doesn't answer 'yes' or 'no' to LWSleeth's question in the beginning post. But it tells us whether it even makes sense to ask that question. Once we figure out whether it makes sense to ask the question, then we would entertain whether the mind is subject to physical effects.

Now that I got all that straightened out let me continue by saying that I just cannot understand the relativity discussion. I understand everything that Janus and Cjames have said. It just doesn't "explain" anything to me. It's almost like the math makes sense but when the words are chosen to convert/interpret that math into language, there's no real explanation. Let me use an analogy and see where that goes.

I have left a 10 dollar bill on the kitchen table. In my absense, my 2 friends are left alone with it. When I return, I find that my money is gone. Someone has stolen it. Now let's say that I ask friend number 1 where my money is. He claims that he saw friend number 2 steal it. When I question friend number 2 he claims that he saw friend number 1 steal the money. Now let's say that they both are telling the truth. From the perspective of each friend, they did nothing wrong(they were at rest). It was the "other" friend that did the stealing. So you can see that this situation has given me no explanation. The question that is unanswered is "how did my money disappear from the table?

I realize that this isn't related to gravity or motion etc. It is only intended to convey to you why I cannot make sense of the relativity explanations thus far. We have a situation where each twin is at rest and blames the distortion on the other twin. Each twin noticed no change because "THERE WAS NO CHANGE". Yet there is an age difference when they get back together. The explanation for this age difference (like my stolen money), has me completely perplexed. I've seen the "time dilation and spatial contraction" comments. But they don't mean much to me. So equate that to my money analogy and tell me what that means.

 

[Les Sleeth]

Originally posted by Janus
The gravity affected the light carrying information between the clocks. The local conditions of each clock are, however, identical.

I think I might have finally understood something. I had to go back and read Einstein's prediction about what would occur if a clock is placed on the equator, and another clock is placed on the North Pole (in that experiment, like your tower example, acceleration factors from circular motion at the equator were discounted). You can see there that the distance traveled between clock "ticks" is longer at the equator than at the North Pole, so the equatorial clock registers fewer ticks than the North Pole clock. I think that made it clear to me how motion dilates time relative to another frame of reference.

In the case you set up Janus, the higher clock in the tower traveled faster in between each tick than did the lower clock; that higher relative speed dilated time for it respective to the lower clock. But then as you brought them closer together, their speeds got closer and closer to one another, and the clocks got more in synch. And when they finally were traveling at the same speed, the ticks once again corresponded but the clocks still reflected the different rates of time they been progressing at before. Correct?

 

[Fliption]

Originally posted by LW Sleeth
I think that made it clear to me how motion dilates time relative to another frame of reference.

You guys don't leave me in the dark. Someone stole my money!

 

[Janus]

Originally posted by LW Sleeth


In the case you set up Janus, the higher clock in the tower traveled faster in between each tick than did the lower clock; that higher relative speed dilated time for it respective to the lower clock. But then as you brought them closer together, their speeds got closer and closer to one another, and the clocks got more in synch. And when they finally were traveling at the same speed, the ticks once again corresponded but the clocks still reflected the different rates of time they been progressing at before. Correct? [/B]

Actually, no. In my case, the only factor involved is the uniform gravity field. You cannot consider factors,(such as sitting on a rotating planet) that are not part of the original scenerio.

 

[Les Sleeth]

Originally posted by Janus
Actually, no. In my case, the only factor involved is the uniform gravity field. You cannot consider factors,(such as sitting on a rotating planet) that are not part of the original scenerio.

I hope you won't give up on us yet.

I don't quite understand your above statement. Are you saying the uniform gravity factor contributed to relativistic effects? I thought you made it common so it wasn't a contributing factor.

Let me ask this as well, would the equator-north pole difference in clocks be for the same reason as in your clock example?

Finally, when you say I added a rotating planet, are you saying motion has nothing to do with the difference in readings? In other words, the higher clock obviously will travel further during one Earth rotation than the lower clock, and so travels at at higher relative speed. But it seems you are saying, you want to eliminate that factor too (along with gravity differences). Would the two separated clocks register different times if you took that tower out in space and let it it rest still there away from any influence of gravity or motion?

 

[Les Sleeth]

Originally posted by ahrkron
Now, even if you assume that thought (or "experience") is not an exclusive result of material processes, you have to agree that there is a close connection between both. Let's say, for the sake of argument, that there is a soul in communication with the brain.

Such soul would learn to estimate/use time using some brain processes (let's say, some stable cycles of activity in some strucutres), and to pace itself according to the time it takes for the brain to transform a "soul-thought" into an electrochemical pattern in the language centers of the brain (or the image-processing centers, depending on how your thought-processes are). This is not only in order to express itself, but also in order to "acquire" some information stored in the brain, to be used as part of its reasoning (or "experiencing", or whatever the soul does).

I was going to wait until I had a better understanding of relativity before I answered you, but since that seems to taking time (and may never happen) I will answer now. I want to preface my comments by saying I consider relativity physical, and whatever "exception" I might suggest is not about relativity but about consciousness.

The way you put it is pretty close to how I would, but before I answer you let me theorize in my terms. In myself I see a part of me observing, controlling, learning and understanding. When I act it is this part of me that wants something. Even though it understands a great variety of things, it seems to be indivisible, singular, or holistic in nature – let’s call it consciousness and refer to its singular nature as integrated. Let’s also assume it is the “real” me, and is what such terms as “I” or “me/my” or “self” refers to from here on.

In my interaction with the world outside of me, my body is the intermediary. It responds to my will and provides me information about the world. The brain is the control center whose organization has taught me how to think, and links me to the rest of my body through the CNS.

The operations of the brain and body are very complex, and I am drawn into that complexity from birth. My senses excite and overwhelm, my brain fascinates, and to survive I must learn to use my physiology effectively. By the time I’ve reached adulthood I am fully absorbed into body and world participation.

While the incessant demands of living virtually enslaves me to physical processes, that original integrated nature of consciousness remains intact. In fact, this element of me can be no other way than “whole,” that’s its inalterable nature. Yet the more I participate in multifaceted activities, the more I lose touch with my underlying integrated nature unless, that is, I specifically were to practice experiencing that part of myself (which I do, and have for many years).

With those ideas in mind . . .

Originally posted by ahrkron
1. If the soul is to notice the change in the "pace of time", it needs to have another way of estimating time, which has to be non-physical in order to be unaffected by relativity. What would this be?

I think this question is really what all your questions are about, so I will use all your questions to gradually answer it. Let me start by explaining how I think the integrated part of consciousness perceives.

The only way the integrated part can detect is by “seeing” and feeling. An analogy to integrated seeing is how we can look at two lengths of boards side by side and see which is longer/shorter. We don’t need to think to see that, we can just “know” by looking. Similarly, as life experience builds, understanding is integrated into consciousness, and it can look at or “see” situations and instantly comprehend without thinking. Now, one might think about what one sees, but I say when someone finally “understands,” that is an integrated event. The feeling part is similar to seeing in that it is an integrated quality of consciousness, and as life experience progresses, it has felt many situations and things. The “feel” of things then contributes to the integrated sort of comprehension that consciousness does.

Originally posted by ahrkron
2. Such "soul-time" can be different for different souls, or the same for all. If different, what sets its pace?, if the same, then there is a preferred physical reference frame after all (the one whose "time pace" coincides with that of all souls)... plus a huge conspiracy that makes the universe look like if such was not the case (why would there be a special physical frame, and yet all physical laws be consistent with no such a thing?).

Regarding what others experience, I’ve only experienced my self, so I cannot speak with absolute certainty about others. But I do suspect it is the same for all for the following reasons.

It is difficult to explain about this unless you are familiar with the element of consciousness I am talking about. I only know about it because I have spent so much time focusing specifically on that part of me. One thing about it is that it seems amazingly constant. No matter what happens to me physically or how upset I might get emotionally, when I turn my attention inside there it is as stable as ever. Seeing that every day all these years makes me of the strong opinion that it isn’t subject to the ups and downs of physical change. I know others who practice doing this, and they report the same thing.

So in the end what it seems like is that that constancy provides a uninterrupted contrast to change (i.e., if one is sufficiently in touch with that part of oneself), and because of that simplicity of course anyone else who was aware of it would have the same inner standard.

I don’t believe there is any “conspiracy.” If you have read any other of my threads you’ve probably heard me reject supernatural ideas. I think that the physical world is the way it is because that’s how it has to be; and the conscious world is the way it is because that is how it has to be. I also can see that most people are caught between the two, and what I think is that since at our core we are consciousness, humans will thrive best if they prioritize and move in that direction. This is precisely why I am here debating with those of the materialist persuasion; to debate what should be prioritized first, consciousness or matter.

Originally posted by ahrkron
3. The strong correlation between brain processes and "soul-experiences" (which we are assuming to be non-causal) put strong constraints on what such experiences can be. Let's say that, after living 30 years on Earth, you start a trip at a speed that corresponds to a time dilation of 1000. Your soul, used to "Earth speed", would have the potential to "experience" 1000 more experiences than before the start of the trip. However, those experiences can be, at most, very peculiar:
__a. They cannot be perceptions (of what is happening on the ship, let's say) since all perceptual information is happening at "physical-time-rate" (both the signals themselves and the neural processes that make them available for the soul are "affected by relativity").
__b. They cannot be "inside talk", since all language-related resources and processes are also at "physical-rate". The same goes for "image-like-thoughts".
__c. They cannot use any information stored in the brain,
__d. Those experiences would not leave the usual imprint on the brain; i.e., you would keep no recollection of them... unless souls were able to keep memories without the help of a brain, and yours decided to wait until appropriate in order to record such experiences on the slow functioning physical brain it now has to deal with (but then... why would we have brains, if souls were able to memorize, reason and decide).

I figure if I am going to get myself into trouble, it will be when I try to answer questions like these. Since I freely admit I don’t have the science expertise that a specialist does, I am not so sure of myself when someone asks me to predict what to expect in a physical situation (especially when I’ve not thought about it before). As of now I can’t answer those questions because I have no experience to base an opinion upon to determine how flexible the integrated part is to extreme relativistic change.

Originally posted by ahrkron
4. Also, the very definition of time comes into play. Is time that which is measured by clocks, or that which has to do with the souls' rate for "experiencing" word-less, image-less, usually unremembered sensations? Even assuming the existence of souls, I think it is much more plausible that time is what clocks measure, that souls can only use physical processes to estimate time or experience experiences, and that no preferred frame exists.

Here is what I can say with most confidence. The integrated part of us is constant and not subject to physical change other than to learn from it. Therefore that background constancy is THE preferred frame of reference, and serves as a contrast to any sort change. I doubt if that contrast would allow the integrated aspect to “see” relativistic change, but I do think it would “feel” the kind of significant change we’ve been visualizing.

 

[Janus]

Originally posted by LW Sleeth
I hope you won't give up on us yet.

I don't quite understand your above statement. Are you saying the uniform gravity factor contributed to relativistic effects? I thought you made it common so it wasn't a contributing factor.

No, I made it uniform to point out that it wasn't the difference in gravitational force that caused the clocks to run at different rates.

Let me ask this as well, would the equator-north pole difference in clocks be for the same reason as in your clock example?

That depends upon what frame you are analyzing the system from.

If you looking at it from the frame that the Earth is rotating with respect to, then part of the difference is due to the Equator clock's relative velocity.

If you are measuring from the Rotating frame, it can be just considered as due to a difference in gravitational potential.

Finally, when you say I added a rotating planet, are you saying motion has nothing to do with the difference in readings? In other words, the higher clock obviously will travel further during one Earth rotation than the lower clock, and so travels at at higher relative speed. But it seems you are saying, you want to eliminate that factor too (along with gravity differences).

I'm trying to simplify the system down so that you won't be mislead by those other factors.

Would the two separated clocks register different times if you took that tower out in space and let it it rest still there away from any influence of gravity or motion?

Not until you introduce a gravity field or acceleraton.

For instance, same situation, but let's put a rocket engine on the base of the tower. Fire it up so that the tower starts to accelerate.

Now we have the same result as before; From the base of the tower the clock at the top appears to run fast, and from the top the clock at the base appears to run slow. Even though the clocks share exactly the same accleration.
Again, if you bring the clocks together, The accumulated elasped time difference will remain.

Now, according to GR, gravitation and acceleration are equivalent, thus any effect caused by acceleration would also be caused by an equivalent gravity field. (In this case, a uniform gravity field, as in my first example.)

 

[Les Sleeth]

Originally posted by Janus
. . . I made it uniform to point out that it wasn't the difference in gravitational force that caused the clocks to run at different rates.

The problem I am having is how you’ve set up the clock tower experiment. Let me tell you how I analyzed the problem so you can see my reasoning process, and if I went wrong somewhere. You set up the first part of the problem as follows:

“Let's use gravitational time dilation as an example. Two clocks are in a tall tower, one at the base and one at the top. And this tower is in a uniform gravity field (one that does change in strength over the height of the tower). At the base, you look up to the clock at the top. The light carrying the info about the clock has to ‘fall’ the Height of the tower. (It has to traverse the Difference in gravity potential.) When it does this it must gain energy. An ordinary object would just pick up energy as extra velocity, but light can't gain velocity, so it gains energy by increasing its frequency. As a result, you will see the clock run faster than yours (this is a Doppler-like effect).”

For relativistic effects to occur, at least two different frames of reference are needed to compare. The at rest frame, and then there are those frames which are either in motion in relation to the rest frame, or those inertially/gravitationally altered in relation to it. So obviously to consider your clock tower problem, I began by looking for what established the two frames of reference (i.e., of the higher clock and the lower clock).

I could see that the difference in clock heights would create a velocity variance, but for this problem you said to discount SR. So that should mean what determines the different reference frames is due to gravity or acceleration.

In your experiment you went on to say, “. . . which clock ‘runs slower’ or ‘runs faster’ merely depends on where you are standing. You can not say in any absolute way that the upper clock runs ‘fast’ or that that Lower clock Runs ‘slow,’ only that relative to each other they run at different speeds.” Okay, by that you meant neither time is the “right” time, but that each time is correct for each frame.

But then you add this, “Now imagine yourself halfway up the tower. The upper clock will appear to run faster and the lower slower. The clocks are on open elevators so that you can see them at all times. You push the buttons so that each clock comes to your level, watching them as they climb or descend. As they do so, you will note that their rates will start to match your own, but the accumulated time difference between them and your clock will remain. Once they become even with you they will click at the same rate as yours, but will show different times. One will have shown more time as having passed, and the other less.”

You added a third reference frame situated midway between the other two. As all three clocks were brought together the time between ticks began to get closer to being the same. At this point two things seemed clear: that the clocks had been ticking at different rates while separated, and that closing the difference in height between them eliminated the difference in ticking rates.

At this point in your problem I was still trying to understand what was differentiating the reference frames. As far as I can see, only GR is left. By leading off with “gravitational time dilation,” and attributing differences in the readings of the clocks to energized EM, you seem to introduce gravity into the problem. Yet you also said that for the sake of understanding your point, I should think of both clocks as in a uniform gravity field, and later you said, “Remember, at all times both clocks were an equal g field so you cannot attribute the difference in their time to the local conditions they were in.” Why is this important to me? Because in your example you say the readings appear to read differently because of the Doppler-like shift, yet when the clocks are brought together they show different times, so more than appearance has happened. The reason for the actual cause of the clock’s different rates of ticking is what I am particularly interested in understanding.

I asked, “Would the two separated clocks register different times if you took that tower out in space and let it rest still there away from any influence of gravity or motion?” You answered, “Not until you introduce a gravity field or acceleration. For instance, same situation, but let's put a rocket engine on the base of the tower. Fire it up so that the tower starts to accelerate. Now we have the same result as before. From the base of the tower the clock at the top appears to run fast, and from the top the clock at the base appears to run slow. Even though the clocks share exactly the same acceleration.”

That confused me because gravity/acceleration, and the clock’s height in relation to gravity/acceleration, is the only thing I can see that establishes the different frames. If you lay the tower down so the clocks are the same height during acceleration, there would be no different frames created. Since you cannot duplicate the relativistic effects by altering the clocks’ heights alone (i.e., in a non-accelerating/gravity field setting), what else can be the cause of not only the appearance of clocks moving at different rates, but the actual difference of intervals between ticks?

Couldn’t it be that acceleration/gravity exerts a constricting effect upon a reference frame? So if we were using light clocks, and were positioned between the upper and lower clocks as before, then we’d see that light had to travel further between mirrors on the upper clock than it did on the lower clock because the lower clock is more strongly affected by gravity/acceleration than the upper clock.

If I have it wrong, I am at a loss to figure out what is distinguishing the frames of reference in your clock tower example.


EDIT: My brain was tired when I wrote the second to last paragraph. I was still thinking of motion. What I meant was:

If an objective observer could be positioned between the upper and lower clocks as before, then he’d see that the upper clock ticked faster than the lower clock because each tick of the lower clock is more strongly constricted by gravity/acceleration than the upper clock.

 

[Janus]

Originally posted by LW Sleeth
The problem I am having is how you’ve set up the clock tower experiment. Let me tell you how I analyzed the problem so you can see my reasoning process, and if I went wrong somewhere. You set up the first part of the problem as follows:

“Let's use gravitational time dilation as an example. Two clocks are in a tall tower, one at the base and one at the top. And this tower is in a uniform gravity field (one that does change in strength over the height of the tower). At the base, you look up to the clock at the top. The light carrying the info about the clock has to ‘fall’ the Height of the tower. (It has to traverse the Difference in gravity potential.) When it does this it must gain energy. An ordinary object would just pick up energy as extra velocity, but light can't gain velocity, so it gains energy by increasing its frequency. As a result, you will see the clock run faster than yours (this is a Doppler-like effect).”

For relativistic effects to occur, at least two different frames of reference are needed to compare. The at rest frame, and then there are those frames which are either in motion in relation to the rest frame, or those inertially/gravitationally altered in relation to it. So obviously to consider your clock tower problem, I began by looking for what established the two frames of reference (i.e., of the higher clock and the lower clock).

I could see that the difference in clock heights would create a velocity variance, but for this problem you said to discount SR. So that should mean what determines the different reference frames is due to gravity or acceleration.

In your experiment you went on to say, “. . . which clock ‘runs slower’ or ‘runs faster’ merely depends on where you are standing. You can not say in any absolute way that the upper clock runs ‘fast’ or that that Lower clock Runs ‘slow,’ only that relative to each other they run at different speeds.” Okay, by that you meant neither time is the “right” time, but that each time is correct for each frame.

But then you add this, “Now imagine yourself halfway up the tower. The upper clock will appear to run faster and the lower slower. The clocks are on open elevators so that you can see them at all times. You push the buttons so that each clock comes to your level, watching them as they climb or descend. As they do so, you will note that their rates will start to match your own, but the accumulated time difference between them and your clock will remain. Once they become even with you they will click at the same rate as yours, but will show different times. One will have shown more time as having passed, and the other less.”

You added a third reference frame situated midway between the other two. As all three clocks were brought together the time between ticks began to get closer to being the same. At this point two things seemed clear: that the clocks had been ticking at different rates while separated, and that closing the difference in height between them eliminated the difference in ticking rates.

At this point in your problem I was still trying to understand what was differentiating the reference frames. As far as I can see, only GR is left. By leading off with “gravitational time dilation,” and attributing differences in the readings of the clocks to energized EM, you seem to introduce gravity into the problem. Yet you also said that for the sake of understanding your point, I should think of both clocks as in a uniform gravity field, and later you said, “Remember, at all times both clocks were an equal g field so you cannot attribute the difference in their time to the local conditions they were in.” Why is this important to me? Because in your example you say the readings appear to read differently because of the Doppler-like shift, yet when the clocks are brought together they show different times, so more than appearance has happened. The reason for the actual cause of the clock’s different rates of ticking is what I am particularly interested in understanding.

The problem you are having is you are trying to distinguish between what ismeasuredfrom each frame and what is actually happening. Relativity makes no such distinction.

Go back to the observer in the middle of the tower. He sees each clock running fast or slow do to the Doppler like effect I mentioned. After a given time by his clock, each of these clocks will appeared to have gained or lost a certain amount of time.

He now brings the clocks to his point of the tower. As he watches them, he's notes that the "Doppler" caused time rate difference decreases for the clocks as they get closer, until it ceases to exist when the clocks are even to him. But the clocks will still appear to lost or gained time. This lost or gained time is purely due to the "doppler" effect he saw earlier. Nothing in bringing the clocks together had a "reverse Doppler" effect, which, from the observer's viewpoint, would have negated this measured time gain or loss.
If there were some other effect that caused the clocks to run at different rates, then the observer would have seen this in addition to the "Doppler" Effect.

In order for this other effect to be the reason for the clocks to show different times when brought together, then there would have to been the "reverse Doppler" effect I already mentioned to cansel out the "Doppler" observed time difference. But I already pointed out that such a reverse effect doesn't exist.

The only cause for the difference in the clocks is the observed "Doppler-like" effect.

I asked, “Would the two separated clocks register different times if you took that tower out in space and let it rest still there away from any influence of gravity or motion?” You answered, “Not until you introduce a gravity field or acceleration. For instance, same situation, but let's put a rocket engine on the base of the tower. Fire it up so that the tower starts to accelerate. Now we have the same result as before. From the base of the tower the clock at the top appears to run fast, and from the top the clock at the base appears to run slow. Even though the clocks share exactly the same acceleration.”

That confused me because gravity/acceleration, and the clock’s height in relation to gravity/acceleration, is the only thing I can see that establishes the different frames. If you lay the tower down so the clocks are the same height during acceleration, there would be no different frames created. Since you cannot duplicate the relativistic effects by altering the clocks’ heights alone (i.e., in a non-accelerating/gravity field setting), what else can be the cause of not only the appearance of clocks moving at different rates, but the actual difference of intervals between ticks?

Again, your are trying to make that distinction between "measurement" and "actuality" that Relativity doesn't.

Let's take another looks at Our accelerating tower. For some one accelerating with the tower, the clocks will appear to run at different rates.

But what about someone that the tower is accelerationg wrt. All he will see is that each clock has a changing velocity wrt himself, and both will appear to run slower and slower as the velocity increases. But each clock has an identical velocity wrt to him so each clock will stay in perfect sync (He will not see the clocks running at different rates.)

The acceleration stops, leaving the tower and the second observer with a constant relative velocity. The observer on the tower will see each clock as showing a different time, while the second observer will see tham as showing the exact same time.

The two clocks are brought together in the center of the ship. They still show the same time difference for the Tower observer.

What happens for the second observer is this:

The two clocks have identical velocities wrt to him until they are being moved together, during this period, each clock has a different velocity wrt to him, the clock at the top, moving to the center will have a velocity slightly less than that of the tower, and the one at the bottom, moving to the center will have a velocity slighty greater. As a result the "top" clock will show a slighty smaller time dilation than the tower and the "bottom" clock will show a slighty greater one. The tp clock will appear to run fater than the bottom clock unitl thaty are brought together and once again share the same realtive velocity. Th eamount of time gained and lost will be exactly that as seen by the tower Observer for different reasons.

To recap, the Tower observer sees the clocks develop a difference during the acceleration phase, and then run at the same rate while being brought together, while the second observer sees the clocks as running at the same rate during the acceleration phase, and develop a time difference while being brought together.

The point being that you can't say that one observer sees what is actually happening while the other only sees what appears to happen. Each observer's observation's are equally valid and are on equally solid ground.

 

[Les Sleeth]

Originally posted by Janus
Again, your are trying to make that distinction between "measurement" and "actuality" that Relativity doesn't.

There are a few things going on in our discussion, and some of it seems to have taken us away from the original idea of this thread. I want to try once more to figure this out.

As I’m sure you’ve discerned, you are talking to a non-professional about physics. My objective in study and contemplation is to have a broad understanding about the universe and its contents. Although I did nearly complete a degree in biology 30 years ago, since then I’ve mostly read books intended to popularize science. In one such book Physics – Concepts and Connections by Art Hobson, he points out the importance of the general population having a solid science understanding because of the “the problems and solutions of our times are bound up with science and its close relative, technology.”

Since we all can’t be scientists, I am grateful for books like Hobson’s. My own specialty is other than science, but I am very interested in and want to understand science fundamentals. You might agree that the best way to get the world on board is for science to be presented in ways everyone can relate to. I guess I am asking for a little flexibility in discussions that involve science. You said, for example, that the “devil is in the details” after I said the details of relativity weren’t that important to the idea behind this thread. I do believe I shouldn’t make any mistakes in my science, but I don’t think it’s important for me understand every element of relativity to set up an essentially non-science hypothetical.

What I think has happened is that you introduced an aspect of relativity beyond my expertise, I was unable to analyze the problem properly, and so we’ve taken off on a separate discussion. Plus, as I will outline below, everything I find appears to contradict at least one thing you seem to be saying (i.e., I freely admit I may be misinterpreting what you mean). This has made me think about and study relativity for week or so, which has been great for me really because I am grateful to be helped by an expert. You’ve been very patient and attentive, and I thank you for that.

But (you probably knew there was a “but” coming), I can’t see how the “details” of relativity change my little thought problem. In this thread I proposed an idea meant to focus on an aspect of consciousness. If you read my response to Ahrkron, I explained that I’ve become intimate with a part of consciousness which seems immune to the incessant change that goes on in the physical (and mental) world. In an indirect way, I was trying to see if I could interest others in noticing that constant aspect of consciousness more.

The purpose of my experiment was to ask if the constant consciousness aspect, after having spent 30 years at Earth’s rate of time, would “notice” on his spaceship journey if his physical circumstances had been altered to a different rate of time. I wasn’t suggesting the brain, the intellect, the senses or any other physical factor might notice, only that constant consciousness aspect. This is the point where you seemed to question the science part of my hypothetical, and it’s why our debate has taken off sideways. How I am interpreting what you seem to be saying is really important if you are correct, because it would mean I am very confused about relativity. Let me explain.

You repeated your objection twice in your last post saying, “The problem you are having is you are trying to distinguish between what is measured from each frame and what is actually happening. Relativity makes no such distinction. . . . Again, you are trying to make that distinction between ‘measurement’ and ‘actuality’ that Relativity doesn't.” However, every physics book I consulted indicated there really is a difference. I called two physics professors at local universities, and they also said there is an “actual” alteration of the time rate in the twins paradox.

Hmmmmm. I am wondering what Janus is saying. I want to understand your point, but I don’t so I pull out a more dedicated physics textbook Modern Physics by Bernstein, Fishbane and Gasiorowicz. I studied the chapter on the basics of relativity and cannot find a basis for your statement, “. . . you are trying to make that distinction between ‘measurement’ and ‘actuality’ that Relativity doesn't.”

Then in your last post I finally realized you were discussing a prediction for relativity concerning the Doppler shift that I had never heard of. Sure enough, the next chapter in the book I was reading addressed it; in fact, the twin’s paradox was invented by Einstein precisely to talk about the relativistic Doppler shift. In the Bernstein, et seq. book they set up the problem by defining the twins as “harmonic oscillators,” and say that their “ages” are simply a measure of the number of pulses they have emitted. Excellent -- I can relate to this since I see time dilation as due to the altering of cycles. Let me quote part of the book that sets up the problem and then specifically addresses my issue:

“We know by now that in specifying the properties of these oscillators [i.e., the twins] we must be careful to state whether they are in motion with respect to an observer, or whether they are at rest. We shall assume that each oscillator has the proper frequency [the authors mean the formal definition of proper]. . . when it is measured at rest in its own frame of reference. Now we send one of the oscillators – the traveling twin, say, twin B – on its trip. The trip is specified in terms of the rest system of the other oscillator – the stay-at-home twin, or twin A – by the following five sequential steps:
1. The oscillator B accelerates to a speed v in a negligible time.
2. It moves away at this constant speed for a long time.
3. It reverses its direction in a negligible time.
4. It returns to the starting point at the same constant speed v.
5. It stops in a negligible time.
“The stay-at-home twin sees the traveling twin’s clock running slow, by time dilation, and would claim that the traveling twin returns having aged less. But we have emphasized the symmetry of relativistic effects. Why can’t the traveling twin claim that in fact he is at rest, while the stay-at-home twin is moving? From this point of view, it is the stay-at-home twin who will have aged less. Which one ages less? This is a question that must have a definite answer, because when the twins get together at the end, they can literally compare their ages. What is wrong with the superficial analysis is that the situations of the twins simply are not symmetric.” [my italics]

The book goes on with an in-depth mathematical analysis that includes allowing the twins to receive pulses from each other so they can calculate how each is aging. After first having the stay-at-home twin calculate his own age based on the pulses, the traveling twin calculates the stay-at-home twin’s age, and then the book states, “This result is identical to the age the stay-at-home twin assigns to himself. The twins have arrived at the same conclusion. The more superficial reasoning at the beginning of the discussion assumed that the two twins were in symmetrical situations. But they are not: One undergoes acceleration and the other does not; there is no symmetry in the situation of the two twins.”

I emphasized the words above with italics because there is exactly what I am talking about. In the twins paradox, the authors point out not only is there an actual aging difference between the twins, but it would be detectable. In your clock tower examples I started looking for situational asymmetry between the clocks to account for the actual difference in aging of the clocks. Even though it has nothing to do with the hypothetical of this thread, it really interests me. Then you seemed to say that one cannot take into account actual aging difference in relativity. Yet every other source I’ve consulted says it is relevant, and so that is where we diverged from the original discussion.

To reiterate, the reason it was important in my hypothetical that an actual change in the rate of time occurred for the traveling twin, is because I set it up that he had had thirty years at Earth’s rate of time. When he traveled, his rate of time was altered from what he was used to. Now although on board ship there would be no indications of that, I was asking, for the reasons I detailed above, if any part of him might nonetheless notice the change. If he really did age slower than he had been used to, that means my hypothetical makes sense. If he doesn’t age differently, then my hypothetical does not make sense. Whether or not you think there is anything within human consciousness that can notice is, of course, another issue.

 

[Janus]

I don't have a lot od time right now but I'll give a short response and then a more detailed one later. I have no real problem with eothr of the sources you quoted. The only thing is that the phrasing used leaves room for misinterpretation by the reader.

When I talked about making a distinction between "actuality" and measurement, I meant just what I said, making a distinction. In Relativity, "What you measure is what you get". Measurement is actuality. What "actually" happens depends upon which frame you are in. The two twins, once brought back into the same frame, agree that their ages differ, They will not agree however, just how this difference was brought about. Nor is there anyway to choose between the twin's separate interpretations of the events leading to the age difference.

This discussion reminds me of the old puzzle. You've probably heard about it. It is the one with the three salesmen, the hotel manager and the bellhop. the gist is that after a series of money transfers, a dollar supposedly comes up missing. The thing is that the "missing dollar" is just an artifice created by the way the end part of the puzzle is worded, The dollar is never really missing.

The simularity, is that your search for what "actually" causes the end time difference is akin to looking for the "missing dollar".