Relativity, a theory of information?

[faen]

I know that the relativistic effects really do happen, such as time dilation and length contraction. However both frames of references predict these effects in the other frame of reference. It is said that these effects really happen in both of them, due to relativity of simultaneity. The thing is that I don't really believe in relativity of simultaneity. Isn't it possible that only one or none of the frames of references make the right prediction. The other frames prediction is then wrong? The measurements between each frames are different events from the ones being measured.

Consider this example. There is observer A on the ground and observer B on a train. Observer A sees two lightning bolts strike the train at both sides simultaneously. Observer A sees that observer B observes the light from the front lightning bolt first, because he travels towards it. Observer B sees that the front lightning bolt strikes at first and then the one behind. He predicts that observer A sees them simultaneously because the lightning bolt at the back strikes when the light from the front bolt is at the same position. So the question is, why aren't just one or none of these predictions the right one according to more absolute properties of time and space?

In the end when two observers arrive at an equal frame of reference, it is only one of them who shows relativistic effects.

 

[Dale]

Isn't it possible that only one or none of the frames of references make the right prediction. The other frames prediction is then wrong? The measurements between each frames are different events from the ones being measured.

Yes, it is possible. The problem is identifying the right frame, it looks just like all of the other ones and behaves as though it doesn't exist.

 

[Naty1]

Isn't it possible that only one or none of the frames of references make the right prediction. The other frames prediction is then wrong?

The 'right' frame ends up being the one you are in. The other frames are right for those observers. The weird thing is that all are correct, yet generally different. One of the other frames is 'right' for you when you are in that frame.

Simultaneity is a tricky 'dude' when time and distance are not agreed upon by different observers, yet the speed of light is agreed upon by different observers...that still seems 'impossible' to me, but it's what we observe, so that's 'reality'...consistently inconsistent! It simply refuses to conform to everyday 'logic'...

 

[bahamagreen]

To the degree that the data one receives (magnitude and sequence) is dependent on one's frame of reference, relativity might very well be characterized as a theory of information, not an existential theory of reality.

An existential theory would require absolute positions, magnitudes, and sequences that would ultimately be comprehensive, complete, and consistent for any measures from each frame of reference, and across all possible frames of reference. From an existential perspective, it does seem peculiar that each observer views his local measures as normal but requires relativistic transforms to interpret measures from a distance or at high speed. The "firm fundamental foundation" aspect of an existential concept of physical reality is just not present in relativity measures.

The sense that ultimate reality must be at least logically existential is what I think has motivated analysis of mathematical structures where comprehensive, complete, and consistent entities can be found that display invariant attributes.

 

[ghwellsjr]

I know that the relativistic effects really do happen, such as time dilation and length contraction. However both frames of references predict these effects in the other frame of reference. It is said that these effects really happen in both of them, due to relativity of simultaneity. The thing is that I don't really believe in relativity of simultaneity. Isn't it possible that only one or none of the frames of references make the right prediction. The other frames prediction is then wrong? The measurements between each frames are different events from the ones being measured.

Consider this example. There is observer A on the ground and observer B on a train. Observer A sees two lightning bolts strike the train at both sides simultaneously. Observer A sees that observer B observes the light from the front lightning bolt first, because he travels towards it. Observer B sees that the front lightning bolt strikes at first and then the one behind. He predicts that observer A sees them simultaneously because the lightning bolt at the back strikes when the light from the front bolt is at the same position. So the question is, why aren't just one or none of these predictions the right one according to more absolute properties of time and space?

In the end when two observers arrive at an equal frame of reference, it is only one of them who shows relativistic effects.

I don't see how your example illustrates your reason to disbelieve relativity of simultaneity or how it illustrates conflicts in measurements between frames since both observers agree as to what the observer sees and predicts. What am I missing?

 

[ghwellsjr]

To the degree that the data one receives (magnitude and sequence) is dependent on one's frame of reference, relativity might very well be characterized as a theory of information, not an existential theory of reality.

Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?

 

[faen]

I don't see how your example illustrates your reason to disbelieve relativity of simultaneity or how it illustrates conflicts in measurements between frames since both observers agree as to what the observer sees and predicts. What am I missing?

I didn't give any reason yet which explains why I disbelieve in relativity of simultaneity. I was just trying to illustrate how it is possible that there could perhaps be an absolute frame of reference? What each frame predicts is not reality, it is just predictions after all.

Also, it seems as though they have different conclusions as well. In the given example, both of them believe that it is the other person who moves and have relativistic effects, leading to different predictions of sequences of events.

The reason I don't believe in relativity of simultaneity is because I think it can be a bit ignorant to only consider what measurements tells us, without taking into account that what we see is actually based on an objective existence. Measurements are nothing but a separate prediction of a true event. What about entanglement? This tells us how particles relate to each other simultaneously regardless of speed.

 

[Dale]

The reason I don't believe in relativity of simultaneity is because I think it can be a bit ignorant to only consider what measurements tells us, without taking into account that what we see is actually based on an objective existence. Measurements are nothing but a separate prediction of a true event.

The problem is that the only "objective existence" that is compatible with the experimental evidence is a type that is consistent with there being no "objective existence". In other words, it doesn't matter if there is one "true frame", it doesn't do anything, so you can ignore it if you want to. Of course, if it comforts you to believe that it is there, then you can imagine it is there, somewhere, lurking in the shadows, completely hidden and impotent. But if you don't want to be bothered with it then you will not get anything wrong by ignoring it either.

 

[nitsuj]

The reason I don't believe in relativity of simultaneity is because I think it can be a bit ignorant to only consider what measurements tells us, without taking into account that what we see is actually based on an objective existence. Measurements are nothing but a separate prediction of a true event. What about entanglement? This tells us how particles relate to each other simultaneously regardless of speed.

Dalespam's retort is well said.

for the part in bold;
"Relate" to each other in the same sense I "relate" to my brother. And that relation exists no matter the spatial seperation. Also regardless of speed.

What does "entanglement" mean to you faen?

 

[bahamagreen]

Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?

You are questioning this?

 

[ghwellsjr]

You are questioning this?

Yes, the OP didn't give an example, can you?

 

[Austin0]

Originally Posted by ghwellsjr View Post

Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?

Yes, the OP didn't give an example, can you?

Not sure where your going here but how about:
Simultaneous light flashes are set off on a train [inertial of course and by train clocks]

In that frame the sequence is simultaneous and the magnitudes of the light spheres are isotropically uniform only varying equally with distance from the sources. No Doppler shift.

In the ground frame they are sequential. The observed magnitude is location dependent and does not vary consistently with distance from the source . There is position dependent Doppler shift.

Perhaps this isn't what you are talking about at all, so maybe you could give an example of what you mean.

 

[ghwellsjr]

Originally Posted by ghwellsjr View Post

Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?

Yes, the OP didn't give an example, can you?

Not sure where your going here but how about:
Simultaneous light flashes are set off on a train [inertial of course and by train clocks]

In that frame the sequence is simultaneous and the magnitudes of the light spheres are isotropically uniform only varying equally with distance from the sources. No Doppler shift.

In the ground frame they are sequential. The observed magnitude is location dependent and does not vary consistently with distance from the source . There is position dependent Doppler shift.

Perhaps this isn't what you are talking about at all, so maybe you could give an example of what you mean.

This isn't what the OP nor what bahamagreen were talking about. They were talking about what an observer sees or measures. You didn't have any observers, did you? Can you put in some observers and demonstrate how what they see or measure is different in the two frames?

 

[Austin0]

This isn't what the OP nor what bahamagreen were talking about. They were talking about what an observer sees or measures. You didn't have any observers, did you? Can you put in some observers and demonstrate how what they see or measure is different in the two frames?

Sorry I thought that observers were implicit as the factors mentioned would apply through out the frames.
So a midpoint train observer would see the flashes as simultaneous and equal in magnitude/brightness and without Doppler shift , other train observers would measure the magnitude as a consistent function of their distance from the sources. No Doppler
A midpoint ground observer would see the rear flash first ,measure it as of lesser magnitude than the front flash even though equidistant and would see the rear blue shifted and the front red shifted.
Another ground observer behind the train but at an equal distance from the rear flash as the mid observer would measure it as having a lesser magnitude and being red shifted . No consistency of the ratio of distance to measured magnitude.Etc,etc...
But maybe I am missing something here and this is still not what you are talking about?
BTW I thought what bahamagreen was talking about was exactly this and thought his view was lucid and to the point.

 

[ghwellsjr]

Sorry I thought that observers were implicit as the factors mentioned would apply through out the frames.
So a midpoint train observer would see the flashes as simultaneous and equal in magnitude/brightness and without Doppler shift , other train observers would measure the magnitude as a consistent function of their distance from the sources. No Doppler
A midpoint ground observer would see the rear flash first ,measure it as of lesser magnitude than the front flash even though equidistant and would see the rear blue shifted and the front red shifted.
Another ground observer behind the train but at an equal distance from the rear flash as the mid observer would measure it as having a lesser magnitude and being red shifted . No consistency of the ratio of distance to measured magnitude.Etc,etc...
But maybe I am missing something here and this is still not what you are talking about?

Now you have a bunch of different observers who all see and measure different things as you described but no mention of which frame(s) you used to determine what they each see and measure. Are you suggesting that if you consider all these observers using the ground frame, they make one set of observations and measurements but if you consider them using the train frame they each make a different set of observations and measurements?

For instance, take your first observer, if you analyzed what he sees using the ground frame (or any other frame), would you conclude that he sees the flashes at different times or with different magnitudes or with a Doppler shift? Or any of the other observers analyzed from any other frame?

 

[ghwellsjr]

I don't see how your example illustrates your reason to disbelieve relativity of simultaneity or how it illustrates conflicts in measurements between frames since both observers agree as to what the observer sees and predicts. What am I missing?

I didn't give any reason yet which explains why I disbelieve in relativity of simultaneity. I was just trying to illustrate how it is possible that there could perhaps be an absolute frame of reference? What each frame predicts is not reality, it is just predictions after all.

Can you be specific about what the characteristics of this absolute frame are? Einstein's Frames of Reference all have an origin (where t=0, x=0, y=0 and z=0). Would this be true of the absolute frame?

Also, it seems as though they have different conclusions as well. In the given example, both of them believe that it is the other person who moves and have relativistic effects, leading to different predictions of sequences of events.

If two frames were identical in every respect except that they had different origins, this would result in them having different conclusions, wouldn't it? Would that be a reason to discount the concept of frames?

The reason I don't believe in relativity of simultaneity is because I think it can be a bit ignorant to only consider what measurements tells us, without taking into account that what we see is actually based on an objective existence. Measurements are nothing but a separate prediction of a true event. What about entanglement? This tells us how particles relate to each other simultaneously regardless of speed.

Isn't what we see a form of measurement? What if we had a precision, calibrated video camera to make measurements, would you discount that? Aren't all measurements just as much objective existence as what we see?

 

[Austin0]

Now you have a bunch of different observers who all see and measure different things as you described but no mention of which frame(s) you used to determine what they each see and measure. Are you suggesting that if you consider all these observers using the ground frame, they make one set of observations and measurements but if you consider them using the train frame they each make a different set of observations and measurements?

For instance, take your first observer, if you analyzed what he sees using the ground frame (or any other frame), would you conclude that he sees the flashes at different times or with different magnitudes or with a Doppler shift? Or any of the other observers analyzed from any other frame?

OK finally I see what your talking about and of course the answer is no. I got from the OP and bahamagreen that the idea was hypothetical direct observation and measurement , not analyzation or calculation which can be done solely from any frame , even this one :-),,,, on a good night.

 

[faen]

Can you be specific about what the characteristics of this absolute frame are? Einstein's Frames of Reference all have an origin (where t=0, x=0, y=0 and z=0). Would this be true of the absolute frame?

I suppose I am trying to get an idea of what space really is. Assuming that one frame is the "right one" makes it possible to imagine an existing mathematical construct of space. Otherwise I really can't think of any mathematical construct of space which is consistent with that all the relativistic "predictions" are true for all frames of references. At least not if I don't believe in relativity of simultaneity.

If two frames were identical in every respect except that they had different origins, this would result in them having different conclusions, wouldn't it? Would that be a reason to discount the concept of frames?

No not that alone. I guess it's for the reason mentioned above, and sceptisism towards relativity of simultaneity.

Isn't what we see a form of measurement? What if we had a precision, calibrated video camera to make measurements, would you discount that? Aren't all measurements just as much objective existence as what we see?

Measurements are evaluated subjectively. Even sight. Thus they are not objective existence. Also the measurements themselves are different events from those measured.

 

[ghwellsjr]

Measurements are evaluated subjectively. Even sight. Thus they are not objective existence. Also the measurements themselves are different events from those measured.

In your first post, you said that "Observer A sees two lightning bolts strike the train at both sides simultaneously". I took that literally as an objective truth. Now you are saying that I was misled, that I should have taken it subjectively, but that just makes it impossible for me to have any idea what you meant. If we can't trust our measurements, then there is no hope of making any sense out of anything. With this level of skepticism, I wonder why you even consider such a thing as an absolute frame or why you are even "trying to get an idea of what space really is".

 

[faen]

In your first post, you said that "Observer A sees two lightning bolts strike the train at both sides simultaneously". I took that literally as an objective truth. Now you are saying that I was misled, that I should have taken it subjectively, but that just makes it impossible for me to have any idea what you meant. If we can't trust our measurements, then there is no hope of making any sense out of anything. With this level of skepticism, I wonder why you even consider such a thing as an absolute frame or why you are even "trying to get an idea of what space really is".

Maybe it was misleading that I said that it is subjective. I do still consider it as information related to the objective caused "somewhere" by objective reality, most likely by determined by the current models/theories we have. Perhaps it's just best to pretend that I didn't say anything about subjective in case it causes any confusion, sorry..

When it comes to the lightning bolts they were measured by the frame of reference to strike simultaneously, but whether they truly did or not is still unknown to me, since perhaps it did not to an absolute/real frame of reference..

 

[Austin0]

Maybe it was misleading that I said that it is subjective. I do still consider it as information related to the objective caused "somewhere" by objective reality, most likely by determined by the current models/theories we have. Perhaps it's just best to pretend that I didn't say anything about subjective in case it causes any confusion, sorry..

When it comes to the lightning bolts they were measured by the frame of reference to strike simultaneously, but whether they truly did or not is still unknown to me, since perhaps it did not to an absolute/real frame of reference..

Here you have it in a nutshell. Because whether they truly did or not is unknown to everybody That was Einsteins brilliant recognition. Just like absolute motion there is simply no means of determination.
The best we get is the purely operational simultaneity of clocks reading the same proper time in a frame, which makes physics work fine, but tells no truth about actual or absolute simultaneity.
I also think there is an objective reality but sadly we can't seem to access it's truth and must make do with only "information". Relative measurements and theories.

 

[ghwellsjr]

In your first post, you said that "Observer A sees two lightning bolts strike the train at both sides simultaneously". I took that literally as an objective truth. Now you are saying that I was misled, that I should have taken it subjectively, but that just makes it impossible for me to have any idea what you meant. If we can't trust our measurements, then there is no hope of making any sense out of anything. With this level of skepticism, I wonder why you even consider such a thing as an absolute frame or why you are even "trying to get an idea of what space really is".

Maybe it was misleading that I said that it is subjective. I do still consider it as information related to the objective caused "somewhere" by objective reality, most likely by determined by the current models/theories we have. Perhaps it's just best to pretend that I didn't say anything about subjective in case it causes any confusion, sorry..

When it comes to the lightning bolts they were measured by the frame of reference to strike simultaneously, but whether they truly did or not is still unknown to me, since perhaps it did not to an absolute/real frame of reference..

OK, so let's agree that any observation or any measurement is objective as far as the data collected is concerned but any extrapolation of that data to what is happening at another location and/or time is subjective--at least that's what I think you are saying.

So when you say that "Observer A sees two lightning bolts strike the train at both sides simultaneously" we take that to be an objective truth because the light from those two bolts arrived at his eyes at the same time but that doesn't mean that the bolts actually occurred at the same time at both sides of the train and to draw that conclusion would be subjective--agreed?

Now let's not be concerned about these subjective aspects but only focus on the objective aspects. What we need is a theory to allow us to make predictions about what different observers will objectively see and measure at different times and when they are not all located at the same place. If a theory can do that, even if the subjective aspects vary all over the place, wouldn't that be a valuable theory?

 

[faen]

Here you have it in a nutshell. Because whether they truly did or not is unknown to everybody That was Einsteins brilliant recognition. Just like absolute motion there is simply no means of determination.
The best we get is the purely operational simultaneity of clocks reading the same proper time in a frame, which makes physics work fine, but tells no truth about actual or absolute simultaneity.
I also think there is an objective reality but sadly we can't seem to access it's truth and must make do with only "information". Relative measurements and theories.

OK, so let's agree that any observation or any measurement is objective as far as the data collected is concerned but any extrapolation of that data to what is happening at another location and/or time is subjective--at least that's what I think you are saying.

So when you say that "Observer A sees two lightning bolts strike the train at both sides simultaneously" we take that to be an objective truth because the light from those two bolts arrived at his eyes at the same time but that doesn't mean that the bolts actually occurred at the same time at both sides of the train and to draw that conclusion would be subjective--agreed?

Now let's not be concerned about these subjective aspects but only focus on the objective aspects. What we need is a theory to allow us to make predictions about what different observers will objectively see and measure at different times and when they are not all located at the same place. If a theory can do that, even if the subjective aspects vary all over the place, wouldn't that be a valuable theory?

Yes, I agree with these two posts. The theory of relativity is a valuable theory which makes the correct predictions. However as with all theories, it is only a model of the "real" reality.

 

[ghwellsjr]

Yes, I agree with these two posts. The theory of relativity is a valuable theory which makes the correct predictions. However as with all theories, it is only a model of the "real" reality.

Well, since you agree that only actual observations and measurements are objective, and extrapolations are subjective, then doesn't that make your idea of a "real" reality subjective?

Here are three more quotes of yours that express the same idea:

So the question is, why aren't just one or none of these predictions the right one according to more absolute properties of time and space?

I was just trying to illustrate how it is possible that there could perhaps be an absolute frame of reference?

I suppose I am trying to get an idea of what space really is. Assuming that one frame is the "right one" makes it possible to imagine an existing mathematical construct of space.

What objective observation or measurement can you make in support of these ideas?

I would suggest that you carefully re-read and study DaleSpam's post #8 and see if it now makes more sense to you.

 

[bahamagreen]

Once you start down the path of comparing observations, models, and reality, you eventually find that all notions of reality are conceptual models.

And if you look closely it gets weird fast. One might believe that the visual image they see is not the reality but some kind of model analogous of that reality, but at least spatially and geometrically it must correspond...
But what happens to that correspondence when you come to notice that the image on the retina is reversed left to right and top to bottom? And that the optic nerve connections to the rods and cones are not made behind the retina, but from the front surface (this is why the retina has a blind spot where the connections pass through it)? And that the part of the brain that processes this information is on the back surface of the brain?
It's even more complicated because the pairs of left and right halves of the two retinae are connected separately and crossed through the optic chiasma serving as the splitting station, then mapped to six layers alternating left and right in a subsequent pair of nuclei to extract spatial information...
And much more... the movement, color, and shape of a single visual object are processed in three different parts of the brain...

This system works very well; we drive cars, play sports, and manage to get around fine, but please rest assured that what you think you see is quite removed from "reality". The dependence of science on instruments and measurements is the history of untangling our naive misconceptions of reality and substituting coherent models, strange as they may seem.

 

[yuiop]

Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?

Take the classic Einstein train example as mentioned in the OP but this time the lightning strike hits the back (Event B) slightly before the strike at the front (Event F) in the reference frame of A who is at rest with the track. He sees light arrive from the back before light arrives from the front. In the reference frame of B who is on board the train and at the centre, light arrives from the front flash before light arrives from the back (If the train is going fast enough) so he concludes that Event F occurred before Event B. (Opposite sequence of events). That is a clear example that the sequence of events depends on the frame of reference. Note also that the sequence in which data is received is also frame dependent.

 

[ghwellsjr]

Can you give an example of where the data one receives (magnitude and sequence) is dependent on one's frame of reference?

Take the classic Einstein train example as mentioned in the OP but this time the lightning strike hits the back (Event B) slightly before the strike at the front (Event F) in the reference frame of A who is at rest with the track. He sees light arrive from the back before light arrives from the front. In the reference frame of B who is on board the train and at the centre, light arrives from the front flash before light arrives from the back (If the train is going fast enough) so he concludes that Event F occurred before Event B. (Opposite sequence of events). That is a clear example that the sequence of events depends on the frame of reference. Note also that the sequence in which data is received is also frame dependent.

The OP did not use any frames in his description of his scenario nor did he mention any remote events. He didn't even say any observers were at the centre of anything. He didn't say this was Einstein's classic train example. None of that is relevant to this discussion. He was talking about what each observer actually sees for himself and what each observer sees that the other observer sees. He does not believe in relativity of simultaneity so he isn't concerned about whether remote events are simultaneous in different frames.

But, to address your concern, of course if you change the scenario, then the observers will see something different than what they saw in the original scenario. That's not the question. The question is for any given scenario, do different Frames of Reference change anything about what each observers sees and measures? In your new scenario, you said the ground observer "sees light arrive from the back before light arrives from the front" and for the train observer "light arrives from the front flash before light arrives from the back." Then you concluded by saying, "the sequence in which data is received is also frame dependent" but you have not shown how this is true because it isn't true. All frames will agree with your two quoted statements about the sequence in which each observer receives the light.

 

[yuiop]

... All frames will agree with your two quoted statements about the sequence in which each observer receives the light.

Your question was not very clear but I see what you are getting at now.
In the scenario I gave:

1)Observer A sees event B before event F.
2)Observer B sees event B after event F.

All (reasonable, intelligent, rational, honest, informed, cogent, sane, sober) observers agree that the above two statements are true.

 

[faen]

Well, since you agree that only actual observations and measurements are objective, and extrapolations are subjective, then doesn't that make your idea of a "real" reality subjective?

Here are three more quotes of yours that express the same idea:



What objective observation or measurement can you make in support of these ideas?

I would suggest that you carefully re-read and study DaleSpam's post #8 and see if it now makes more sense to you.

Yes theories are subjective. However if we were to learn about the reality in more fundamental terms, it could turn out that an absolute frame of reference is a more symmetric describtion with what is "real". At least I was interrested in if it could be a possibility.

Once you start down the path of comparing observations, models, and reality, you eventually find that all notions of reality are conceptual models.

And if you look closely it gets weird fast. One might believe that the visual image they see is not the reality but some kind of model analogous of that reality, but at least spatially and geometrically it must correspond...
But what happens to that correspondence when you come to notice that the image on the retina is reversed left to right and top to bottom? And that the optic nerve connections to the rods and cones are not made behind the retina, but from the front surface (this is why the retina has a blind spot where the connections pass through it)? And that the part of the brain that processes this information is on the back surface of the brain?
It's even more complicated because the pairs of left and right halves of the two retinae are connected separately and crossed through the optic chiasma serving as the splitting station, then mapped to six layers alternating left and right in a subsequent pair of nuclei to extract spatial information...
And much more... the movement, color, and shape of a single visual object are processed in three different parts of the brain...

This system works very well; we drive cars, play sports, and manage to get around fine, but please rest assured that what you think you see is quite removed from "reality". The dependence of science on instruments and measurements is the history of untangling our naive misconceptions of reality and substituting coherent models, strange as they may seem.

I am not disbelieving in any measurements though. I am aware of that all my beliefs about reality are based on some kind of measurement.

 

[ghwellsjr]

Yes theories are subjective. However if we were to learn about the reality in more fundamental terms, it could turn out that an absolute frame of reference is a more symmetric describtion with what is "real". At least I was interrested in if it could be a possibility.

After more than a century of intense searching, there doesn't appear to be any hope that an absolute frame of reference could be objectively determined.

Now the question is: are you interested in learning Special Relativity or do you already understand it but just don't believe it?

 

[faen]

After more than a century of intense searching, there doesn't appear to be any hope that an absolute frame of reference could be objectively determined.

Now the question is: are you interested in learning Special Relativity or do you already understand it but just don't believe it?

I am interested in the theory in general and learning more about it wherever I can. I believe I understand the basic concepts. I am open for the possibility of relativity of simultaneity, but I am sceptic towards it as well. As of now, if I would have to make a bet, I would put my money on that relativity of simultaneity is not true.

 

[ghwellsjr]

I am interested in the theory in general and learning more about it wherever I can. I believe I understand the basic concepts. I am open for the possibility of relativity of simultaneity, but I am sceptic towards it as well. As of now, if I would have to make a bet, I would put my money on that relativity of simultaneity is not true.

Relativity of simultaneity is one of the basic concepts of Special Relativity. Is it one that you believe you understand? Or do you think you need to learn more about it? Either way, can you summarize what you believe it means?

 

[faen]

Relativity of simultaneity is one of the basic concepts of Special Relativity. Is it one that you believe you understand? Or do you think you need to learn more about it? Either way, can you summarize what you believe it means?

If you have two different frame of references, A and B. Events which are simultanous in A, exists as not simultaneous to B. That's what I'm skeptic about..

However, that they both predict that the events in the other frame are not simultaneous makes sense, and that is true.

 

[ghwellsjr]

If you have two different frame of references, A and B. Events which are simultanous in A, exists as not simultaneous to B. That's what I'm skeptic about..

However, that they both predict that the events in the other frame are not simultaneous makes sense, and that is true.

What is meant by "event"?

 

[faen]

What is meant by "event"?

That something happens I guess. A change in the universe.

 

[ghwellsjr]

In Special Relativity "event" has a very specific meaning but before we get to that, we need to cover some basic ground work. Could you please read section 1 of Einstein's 1905 paper introducing Special Relativity and note especially how many times he uses the word "define" or variations? See if you understand what he is saying.

 

[faen]

In Special Relativity "event" has a very specific meaning but before we get to that, we need to cover some basic ground work. Could you please read section 1 of Einstein's 1905 paper introducing Special Relativity and note especially how many times he uses the word "define" or variations? See if you understand what he is saying.

It's kinda long to read and I've already read the basics about special relativity before.. Could you please summarize what he means with define and variations if possible?

 

[ghwellsjr]

It's barely a page--I didn't mean the whole first part--just the first section called "Definition of Simultaneity". Can you at least read through it and tell me how many times he uses the word "define" or its variations?

 

[faen]

It's barely a page--I didn't mean the whole first part--just the first section called "Definition of Simultaneity". Can you at least read through it and tell me how many times he uses the word "define" or its variations?

Oh then it's no problem, I thought it was the whole kinematics part. It seems as if he defines simultaneity as when the clocks between two different frames measures the same time of light traveling back and forth. Which means that the frames are at equal speed.

It doesn't say anything there about how he defines unsimultaneous events. Does he believe that they are truly unsimultaneous, or just measured unsimultaneous? I get the impression that he doesn't conclude anything further than what can be measured.

I'm thinking about something like minkowsky space, that what is present for frame A, is something completely different from what is currently present at frame B. That is what I'm skeptic about.

A person wrote a book about how he believes that he has disproved presentism. What would your opinion be about something like that? Parts of his book is below in case you're interrested. I think the first page from the link would give an idea of his views.

http://books.google.hu/books?id=Azf...KpaDaCQ&sqi=2&redir_esc=y#v=onepage&q&f=false

 

[Dale]

I get the impression that he doesn't conclude anything further than what can be measured.

That is all that science can investigate. If there is something that cannot be measured then it is not amenable to investigation by the scientific method which relies on the outcome of experimental measurements to confirm or reject hypotheses.

The problem is not the science, but your desire for more than the science can provide. If you want more than what can be measured then you need to consult a preist or a philosopher, not a scientist.

 

[faen]

That is all that science can investigate. If there is something that cannot be measured then it is not amenable to investigation by the scientific method which relies on the outcome of experimental measurements to confirm or reject hypotheses.

The problem is not the science, but your desire for more than the science can provide. If you want more than what can be measured then you need to consult a preist or a philosopher, not a scientist.

I would disagree here. You can not measure every single molecule/atom, yet you assume that it is molecules/atoms constituting all of matter.

 

[ghwellsjr]

It's barely a page--I didn't mean the whole first part--just the first section called "Definition of Simultaneity". Can you at least read through it and tell me how many times he uses the word "define" or its variations?

Oh then it's no problem, I thought it was the whole kinematics part. It seems as if he defines simultaneity as when the clocks between two different frames measures the same time of light traveling back and forth. Which means that the frames are at equal speed.

It doesn't say anything there about how he defines unsimultaneous events. Does he believe that they are truly unsimultaneous, or just measured unsimultaneous? I get the impression that he doesn't conclude anything further than what can be measured.

I'm thinking about something like minkowsky space, that what is present for frame A, is something completely different from what is currently present at frame B. That is what I'm skeptic about.

A person wrote a book about how he believes that he has disproved presentism. What would your opinion be about something like that? Parts of his book is below in case you're interrested. I think the first page from the link would give an idea of his views.

http://books.google.hu/books?id=Azf...KpaDaCQ&sqi=2&redir_esc=y#v=onepage&q&f=false

Before you get into such things as minkowsky space or presentism, you need to thoroughly understand Special Relativity and by that time, maybe you won't care. At least I don't care about those things.

Now, you somehow got the idea that Einstein was talking about two different frames of reference in that first section of his paper and that they were traveling at some speed. He actually is defining the concept of what a frame is and he calls it the "stationary frame" so he's not concerned about any speeds (except the speed of light) at this point.

So let me take you through how Einstein is showing us how to create a Frame of Reference or a system of coordinates. He does this with a series of definitions. The first definition is with regard to the three spatial components where he says we use "rigid standards of measurement" or rulers at right angles to each other.

The next definition has to do with time where he says that we use the reading of a clock located next to the event we want to associate time with. And if we want to attach a time to two events that are located some distance from each other, we need two identical clocks and we need a definition of how to synchronize those two clocks.

To illustrate how this is done, he envisions a setup involving one clock at location A with a light source that can emit a flash and at location B, some distance away, measured with a rigid ruler is a mirror and a second clock. When the flash is emitted at location A, the time on clock A, t_A is noted. Then when the flash reaches the mirror, the time on clock B, t_B is noted. Finally, when the reflection of the flash returns to A, the time t'_A is noted.

He states that the round trip speed of light can be calculated by taking double the distance between the two clocks (2AB) and dividing it by the total time interval it took for the light to make the round trip (t'_A-t_A) and that experiments have shown this to always equal the universal constant, c.

But, we cannot know what time between t_A and t'_A the light arrived at location B unless we supply a definition. In other words, we don't know what portion of the total time the light took to get from A to B as compared to getting from B back to A. Without a definition, we have a subjective situation but with a definition, we make it objective. And Einstein's definition is to make those two time intervals equal. So after doing the experiment we see if t_B-t_A, the time interval for the first portion of the trip is equal to t'_A-t_B, the time interval for the second portion of the trip. If they are, then the two clocks are synchronized. If not, we change the time on clock B to make them equal and we repeat the test to see if we have performed the synchronization correctly and we repeat until we have.

Now that we know how to synchronize a clock located at a remote location from a master clock, we place clocks at numerous locations throughout our 3-dimensional grid of rulers and make sure they are all synchronized to the clock at the spatial origin of the co-ordinate system. So now if we want to know the co-ordinates of any event, we look at the readings on the 3-dimensional grid of rulers and the time on the synchronized clock at the location of the event.

Thus, an "event" in Special Relativity is the four co-ordinates (three spatial and one temporal) defined according to a specified Frame of Reference.

What I want you to notice is that Einstein's definition of a Frame of Reference makes objective what previously had been subjective.

So now if you want to know if two events are at the same location, you look at their respective three spatial co-ordinates. If they match, they are at the same location, even if they are at different times. In exactly the same way, if you want to know if two events are at the same time, you look at their time co-ordinates. If they match, they are simultaneous even if they are at different locations. If they don't match, then they are, as you say, unsimultaneous.

Remember, we are just talking about co-ordinates defined according to a given Frame of Reference that we have "constructed".

Of course, someone else can construct a different Frame of Reference with a different origin (for both the spatial and temporal co-ordinates), with the axes pointing in different directions, and moving with respect to our Frame of Reference and then we would expect the co-ordinates to be all different, wouldn't we? But we shouldn't find that disturbing, it's purely a result of a different Frame of Reference.

Does this all make sense to you?

 

[Dale]

You can not measure every single molecule/atom

Why not? Given some molecule/atom X why couldn't you measure it? Given some collection of molecules/atoms why couldn't you measure every single one?

The only limitations I can think of are economic, not scientific.

This is fundamentally different from what you are asking, which cannot be measured even in principle regardless of economic or technological resources contemplated.

 

[faen]

Before you get into such things as minkowsky space or presentism, you need to thoroughly understand Special Relativity and by that time, maybe you won't care. At least I don't care about those things.

Now, you somehow got the idea that Einstein was talking about two different frames of reference in that first section of his paper and that they were traveling at some speed. He actually is defining the concept of what a frame is and he calls it the "stationary frame" so he's not concerned about any speeds (except the speed of light) at this point.

So let me take you through how Einstein is showing us how to create a Frame of Reference or a system of coordinates. He does this with a series of definitions. The first definition is with regard to the three spatial components where he says we use "rigid standards of measurement" or rulers at right angles to each other.

The next definition has to do with time where he says that we use the reading of a clock located next to the event we want to associate time with. And if we want to attach a time to two events that are located some distance from each other, we need two identical clocks and we need a definition of how to synchronize those two clocks.

To illustrate how this is done, he envisions a setup involving one clock at location A with a light source that can emit a flash and at location B, some distance away, measured with a rigid ruler is a mirror and a second clock. When the flash is emitted at location A, the time on clock A, t_A is noted. Then when the flash reaches the mirror, the time on clock B, t_B is noted. Finally, when the reflection of the flash returns to A, the time t'_A is noted.

He states that the round trip speed of light can be calculated by taking double the distance between the two clocks (2AB) and dividing it by the total time interval it took for the light to make the round trip (t'_A-t_A) and that experiments have shown this to always equal the universal constant, c.

But, we cannot know what time between t_A and t'_A the light arrived at location B unless we supply a definition. In other words, we don't know what portion of the total time the light took to get from A to B as compared to getting from B back to A. Without a definition, we have a subjective situation but with a definition, we make it objective. And Einstein's definition is to make those two time intervals equal. So after doing the experiment we see if t_B-t_A, the time interval for the first portion of the trip is equal to t'_A-t_B, the time interval for the second portion of the trip. If they are, then the two clocks are synchronized. If not, we change the time on clock B to make them equal and we repeat the test to see if we have performed the synchronization correctly and we repeat until we have.

Now that we know how to synchronize a clock located at a remote location from a master clock, we place clocks at numerous locations throughout our 3-dimensional grid of rulers and make sure they are all synchronized to the clock at the spatial origin of the co-ordinate system. So now if we want to know the co-ordinates of any event, we look at the readings on the 3-dimensional grid of rulers and the time on the synchronized clock at the location of the event.

Thus, an "event" in Special Relativity is the four co-ordinates (three spatial and one temporal) defined according to a specified Frame of Reference.

What I want you to notice is that Einstein's definition of a Frame of Reference makes objective what previously had been subjective.

So now if you want to know if two events are at the same location, you look at their respective three spatial co-ordinates. If they match, they are at the same location, even if they are at different times. In exactly the same way, if you want to know if two events are at the same time, you look at their time co-ordinates. If they match, they are simultaneous even if they are at different locations. If they don't match, then they are, as you say, unsimultaneous.

Remember, we are just talking about co-ordinates defined according to a given Frame of Reference that we have "constructed".

Of course, someone else can construct a different Frame of Reference with a different origin (for both the spatial and temporal co-ordinates), with the axes pointing in different directions, and moving with respect to our Frame of Reference and then we would expect the co-ordinates to be all different, wouldn't we? But we shouldn't find that disturbing, it's purely a result of a different Frame of Reference.

Does this all make sense to you?

Yes I understand this. However, I am still seeking or interested in a deeper perspective as well. Or I'm still a presentist I'd say. Your explanation was still helpful in widening my perspective though since I didn't know of that way of defining simultaneity.

 

[faen]

Why not? Given some molecule/atom X why couldn't you measure it? Given some collection of molecules/atoms why couldn't you measure every single one?

The only limitations I can think of are economic, not scientific.

This is fundamentally different from what you are asking, which cannot be measured even in principle regardless of economic or technological resources contemplated.

Perhaps you could measure all the molecules, but you didn't. Taking into account that you still didn't measure all the molecules, you still believe that they constitute matter.

Do you believe that it is impossible that scientists will have a deeper understanding of the theory of relativity in the future?

Since you mentioned philosophy, I'd say that many philosophical theories can be scientific as well. For example that only one of the frames is "really" stationary, could be such a theory. It would then be based on the observation that time goes relatively slower in a frame. Fundamental reasons such as equal laws in all frames, causes them to still be uninformed about who is moving. Or perhaps there could be different layers of space moving relative to each other.. Those assumptions are fundamentally based on generalizing observations. It can't be tested which of any such assumption could be a correct one, or is it sufficient with the observations which they are already based on if such a theory is consistent? Nothing can be proven with 100% certainty anyway. Also, is string theory proven by experiments as well?

 

[ghwellsjr]

Yes I understand this. However, I am still seeking or interested in a deeper perspective as well. Or I'm still a presentist I'd say. Your explanation was still helpful in widening my perspective though since I didn't know of that way of defining simultaneity.

Well, I'm glad that helped because it is the basis of Special Relativity.

I mentioned earlier how another observer could create his own Frame of Reference with totally different co-ordinates and how that shouldn't be disturbing. Do you understand this and do you agree it's nothing to be disturbed about?

 

[Dale]

Since you mentioned philosophy, I'd say that many philosophical theories can be scientific as well.

If it can be experimentally tested then it is science, if it cannot then it is not science. That is the key defining characteristic of science. It seems like you have a misunderstanding of what constitutes science.

http://en.wikipedia.org/wiki/Science

 

[faen]

Well, I'm glad that helped because it is the basis of Special Relativity.

I mentioned earlier how another observer could create his own Frame of Reference with totally different co-ordinates and how that shouldn't be disturbing. Do you understand this and do you agree it's nothing to be disturbed about?

Yes I realize this. However it is only measurements of the surface of something more mysterious.

 

[faen]

If it can be experimentally tested then it is science, if it cannot then it is not science. That is the key defining characteristic of science. It seems like you have a misunderstanding of what constitutes science.

http://en.wikipedia.org/wiki/Science

I think I understand this concept better than whatever philosophers even came up with this idea. Anyway, this is the first link which came up when I googled if string theory is experimentally tested. http://io9.com/5714210/string-theory-fails-first-major-experimental-test

This means that string theory isn't physics anymore? Or perhaps you could explain to me why string theory is still science even if it can't be experimentally verified?

 

[Dale]

I think I understand this concept better than whatever philosophers even came up with this idea.

What are you referring to by "this idea" and "this concept"?

Anyway, this is the first link which came up when I googled if string theory is experimentally tested. http://io9.com/5714210/string-theory-fails-first-major-experimental-test

This means that string theory isn't physics anymore? Or perhaps you could explain to me why string theory is still science even if it can't be experimentally verified?

That link is a pop-sci link, not a scientific reference, so I am not sure about the report at all. However, I agree in general that string theory is not exempt from the experiment requirement. In order to be a scientific theory it must make experimentally testable predictions.