Relativity - Oh dear, here we go again!

[ynot]

(I can here the moans from around the world

It seems to me that Relativity is claiming that observing the reality of one rest frame, from the reality of another rest frame, creates a new and different reality of the observed reality.

To explain what I mean I will use the light clock thought experiment as an example. Instead of a light clock however, let’s imagine a more “human friendly” clock. Our clock consists of a metre long clear glass tube with parallel end caps. Inside the tube, a ball continuously bounces up and down between the end caps. The ball has the same property as light in that it can only move at one speed. One of the end caps has a clock face that registers a second every time the ball hits it.

According to Relativity (as I understand it): When the clock is observed from within its own rest frame (A), the ball will bounce directly up and down between the end caps and the clock will function correctly. When observed from a different rest frame (B) however, the clock will not function correctly. This is because when (A) and (B) rest frames pass each other, (B) observes that the ball in the clock not only bounces up and down between the end caps, but it also moves sideways. This means that (B) observes that the ball is moving between the end caps in a zigzag manner, and therefore has to travel a greater distance to bounce from one end cap to the other. As the ball cannot increase its speed, it takes longer for the ball to bounce between the caps and the clock therefore runs slower.

The problem I have in accepting this is that Relativity seems to be claiming that observing the clock from a different rest frame creates another actual version of the same clock. I believe that objects (such as the clock) only have actual existence within their own reference frame. In other words, an object only exists once, as it is, where it is. That objects can be observed from different reference frames, doesn’t mean that other actual versions of the objects are created. (B) observes that the clock is moving sideways but it isn’t. It’s “at rest” in its rest frame (A) and the ball therefore is never actually moving in a zigzag manner. It is just being wrongly perceived by (B) that it is.

Look at a film strip and you observe a series of individual still pictures in many frames. Run the film strip through a projector at the correct speed and you will observe that the pictures are merged together as a single moving picture in a single frame. Obviously this is an optical illusion (unless Relativity says that it‘s not . That (B) observes that the clock is moving sideways and the ball is moving in a zigzag manner, is also an optical illusion. In the “movie illusion“ the many individual pictures of the film strip are being merged in to a single picture. In the “Relativity illusion” the single clock is being separated in to many individual versions of the clock. In reality the clock can only exist once.

Lets take the human elements (peripheral vision, memory, anticipation, etc) out of the clock experiment as much as possible and see what the result is. Instead of directly observing the passing clock, an observer (Bx) in rest frame (B) is in an enclosed structure and is viewing the passing clock on a screen via a live feed from a movie camera mounted on the structure (same rest frame as the observer). The camera is computer controlled and masks everything out of the picture other than the clock. The camera also zooms in and out as the clock passes to keep it at the same size when observed by (Bx). Essentially (Bx) would observe the clock as if it was being observed from rest frame (A). The clock wouldn’t appear to be moving sideways and the ball wouldn’t appear to be moving in a zigzag manner.

I welcome any constructive feedback on

 

[Delusions_O_Grandeur]

It is my experience that special relativity is easier to understand after you worked through a good textbook. You might want to try "A traveller's guide to space-time" by Thomas A Moore. It's the book I used for the subject SR during my physics course. You do need a basic understanding of algebra though. (Things like a^2 + b^2 = c^2 and a few simple integrals).

 

[ynot]

It is my experience that special relativity is easier to understand after you worked through a good textbook. You might want to try "A traveller's guide to space-time" by Thomas A Moore. It's the book I used for the subject SR during my physics course. You do need a basic understanding of algebra though. (Things like a^2 + b^2 = c^2 and a few simple integrals).

If the basis on which the math is founded is incorrect, surely that makes the use of the math redundant. To put it another way, I don’t think reality can be reverse engineered from math. Lets get the observations right before we move to the math. I don’t expect that what I have explained is correct. I just can’t see where I’m wrong. Non-math feedback would be appreciated

 

[ynot]

Several interpretations of E=MC₂ . . .

Mathematician - E = Energy, M = Mass and C = speed of light

Theist - E = Existence, M = Miracle, and C = Creation

Relativity Sceptic - E = Einstein, M = Mathematical and C = Conjurer

<< means I'm joking

 

[Atlas]

I'm not sure I understand the distinction you're making.

Math has no affect on reality. It helps us quantify our own subjective observations. When the roofer pounds nails on the house while I watch in the street I notice that I hear his strikes while the hammer is in the air. There is no secondary reality. He exists pounding on the roof and I have a deformed subjective experience of what's happening. Math can help me understand what is happening and also what I would experience if I moved closer or farther away.

 

[LordoftheLeftHand]

If the basis on which the math is founded is incorrect, surely that makes the use of the math redundant.

IF the basis on which math is founded is incorrect, how do you know you get the right change at the store?

LLH

 

[ynot]

I didn’t say that basis on which math per se is founded is incorrect. I’m saying that it seems to me that the math used in relation to the clock experiment is founded on the properties of an illusion. And just because the illusion can be expressed accurately mathematically, it doesn’t mean the illusion accurately represents the actual reality of the hammer hitting the nail (I love math by the way). As Atlas said, the distant observation of the hammer hitting the nail is “deformed” (an audio/visual illusion). In other words, it’s not an accurate representation of the hammer hitting the nail. The reality is that the sound is generated the instant the hammer hits the nail.

ETA - The reality in the clock experiment is that the clock never moves sideways and the ball never moves in a zigzag manner.

 

[Wolfman]

Guys, be nice. Ynot clearly wasn't saying that mathematics itself has no foundation, only that a nice mathematical equation doesn't prove something is real (in fact, there have been a number of very nice mathematical equations for quantum physics that looked very nice, very elegant in fact, but that subsequently proved not to actually reflect reality).

I myself am pretty much math-illiterate, so just throwing an equation at me and saying "this proves it" doesn't, in fact, prove a thing -- except that I'm supposed to accept, on blind faith, claims about something I don't really understand.

I think that ynot would appreciate more of a "layman's explanation", a simplified version that doesn't require mathematical formulae. I'd give it a shot, but quite frankly while I think I understand it better than ynot, I'm far from being a professional in this area, and expect that others can do a far better job at it than I can. In particular, I'd focus on the fact that ynot doesn't seem to me to be saying, "Prove it to me"...it seems to be more a question of "Explain how it works".

 

[PixyMisa]

The problem I have in accepting this is that Relativity seems to be claiming that observing the clock from a different rest frame creates another actual version of the same clock.

I can't see how you managed to get that out of it.

Observing the clock from a different frame of reference results in different observations of the same clock. That's the entire point.

 

[ynot]

I can't see how you managed to get that out of it.

Observing the clock from a different frame of reference results in different observations of the same clock. That's the entire point.

If that was what was being claimed by Relativity there would be no problem (for me). It seems to me however that Relativity is claiming that a different frame observation of the clock is creating a different reality of the clock. It’s not said that the clock seems to be running slower, it is said that it is running slower

 

[ynot]

Guys, be nice. Ynot clearly wasn't saying that mathematics itself has no foundation, only that a nice mathematical equation doesn't prove something is real (in fact, there have been a number of very nice mathematical equations for quantum physics that looked very nice, very elegant in fact, but that subsequently proved not to actually reflect reality).

Thanks, but I don‘t need them to be nice (I thought they were being anyway). I would rather they beat me up if they do using logic and reason and prove where I‘m wrong.

I myself am pretty much math-illiterate, so just throwing an equation at me and saying "this proves it" doesn't, in fact, prove a thing -- except that I'm supposed to accept, on blind faith, claims about something I don't really understand.

I think that ynot would appreciate more of a "layman's explanation", a simplified version that doesn't require mathematical formulae. I'd give it a shot, but quite frankly while I think I understand it better than ynot, I'm far from being a professional in this area, and expect that others can do a far better job at it than I can. In particular, I'd focus on the fact that ynot doesn't seem to me to be saying, "Prove it to me"...it seems to be more a question of "Explain how it works".

A non-mathematical explanation doesn’t have to be a "layman's explanation". Taking the math away isn’t “dumbing it down” as far as I’m concerned. Don’t know on what grounds you claim to “understand it better”. Perhaps it’s because you are happier to accept it? I think I have a reasonable understanding of how it “works” so I would rather have what I have said challenged and explained where it is wrong.

 

[my_wan]

Yes trying to mix concepts born from the interpretation of Quantum Mechanics in Relativity is common. In a sense the change in perspective in Relativity is like the rubber pencils trick. The difference being that the pencil trick is due to a limited visual processing speed. Relativity defines a limited speed of information of reality. Try another perception experiment. Drop a small but heavy rock from a moving car. You will see that except for wind resistance the rock appears to drop straight down. However to the person standing by the road the rock appears to fall at an angle. It is no different in Relativity with your tube.

The big difference with Relativity is that what is space for one person can be time for another. This is not because space actually becomes something different (time) but because space is defined by the time it takes to move through it. In the relativity of rigidity it can appear that solid objects bend etc. The end result is nonetheless exactly what you would expect without relativity (like the pencil). The caveat being that separate clocks at different points on the object may not agree on how long it took. No need for separate realities when the changes in relative time completely defines the whole thing

 

[Fredrik]

First of all, observations don't create anything. All the inertial systems exist independenly of physical observers. (This isn't something that can be explained very well without going into the mathematics).

The clock is running slower in the other frame, but this doesn't mean that we're talking about two different "realities". We're just talking about two different points of view. Think of a cylinder for example. Viewed from the top, it looks like a circle. Viewed from the side it looks like a rectangle. But it's still just one object. We just can't see the whole thing just by looking at it from one direction.

This analogy is better than you think. The whole existence of the clock is four-dimensional, not three-dimensional. (The fourth dimension is time). What we're doing when we're observing it is equivalent to slicing up this four-dimensional object into three-dimensional objects and looking at these slices one at a time. When another inertial observer is observing the same clock, he's also slicing up the same four-dimensional object into three-dimensional objects, but if he's moving relative to us, he's not slicing it the same way! This is why he will see something different.

So the two different observers are describing the same four-dimensional reality. The only thing they really disagree about is which three-dimensional slices of space-time they should call "space".

If you feel even more confused after reading this, you might want to check out some of the literature on the subject. In my opinion, the best way by far to understand the basics of SR is to learn to draw space-time diagrams. My favorite book on special relativity is "An introduction to general relativity" by Bernard Schutz. Yes, I know the title says general relativity, but it has a chapter about special relativity that's just brilliant.

 

[BillyJoe]

It seems to me that Relativity is claiming that observing the reality of one rest frame, from the reality of another rest frame, creates a new and different reality of the observed reality.

Iv'e never seen it that way.
For me, the word "relative" says it all.
How an event appears depends on what reference frame you observe it from. But there is only one event, not several versions of the same event. That is correct.

According to Relativity (as I understand it): When the clock is observed from within its own rest frame (A), the ball will bounce directly up and down between the end caps and the clock will function correctly. When observed from a different rest frame (B) however, the clock will not function correctly. This is because when (A) and (B) rest frames pass each other, (B) observes that the ball in the clock not only bounces up and down between the end caps, but it also moves sideways. This means that (B) observes that the ball is moving between the end caps in a zigzag manner, and therefore has to travel a greater distance to bounce from one end cap to the other. As the ball cannot increase its speed, it takes longer for the ball to bounce between the caps and the clock therefore runs slower.

I don't think you need to use the word "rest". Our own frames are always at rest from our point of view, so that word is redundant.
Other than that, you are spot on here with your description as far, as I can tell.

The problem I have in accepting this is that Relativity seems to be claiming that observing the clock from a different rest frame creates another actual version of the same clock.

It might "seem" that way to you, but that is not what SR is actually saying. Again think of that all important word "relative".

I believe that objects (such as the clock) only have actual existence within their own reference frame. In other words, an object only exists once, as it is, where it is.

It's hard to disagree with "an object only exists once". That is, in fact, the case. SR doesn't actually say any different. But I'm still struggling to see why you think SR seems to be saying something else.
And I'm not sure what point you are making when you say that "an object only has actual existence within their own reference frame". It certainly doesn't have any existence outside it's reference frame. I mean it is where it is where it is. It's certainly nowhere else.

That objects can be observed from different reference frames, doesn’t mean that other actual versions of the objects are created.

Of course not. There is only one object (contained within it's own reference frame).

(B) observes that the clock is moving sideways but it isn’t. It’s “at rest” in its rest frame (A) and the ball therefore is never actually moving in a zigzag manner. It is just being wrongly perceived by (B) that it is.

From the reference frame of B, the clock IS moving sideways as well as up and down.
This is actually no different from someone bouncing a ball inside a passing train. From the POV of the person bouncing the ball, the ball simply bounces up and down. From the POV of a person standing at the station, the ball moves sideways as it bounces up and down.
There is obviously only one ball.

Look at a film strip and you observe a series of individual still pictures in many frames. Run the film strip through a projector at the correct speed and you will observe that the pictures are merged together as a single moving picture in a single frame. Obviously this is an optical illusion

The smooth movement is the optical illusion. The underlying reason is that the image on the retina (or in our brain) persists for about .04 seconds - long enough for the second image to appear if the film is run at 24 frames a second. Slow it down and you will observe that the smooth movement is lost.
I don't see an analogy with SR...

That (B) observes that the clock is moving sideways and the ball is moving in a zigzag manner, is also an optical illusion. In the “movie illusion“ the many individual pictures of the film strip are being merged in to a single picture. In the “Relativity illusion” the single clock is being separated in to many individual versions of the clock. In reality the clock can only exist once.

It only exists once, period.

How it acts is different depending on what frame of reference you are observing it from.
On the train: up and down.
On the train station: up and down while moving sideways.
On the spaceship: up and down.
On the space station: up and down while moving sideways.

I don't really see the problem.

Lets take the human elements (peripheral vision, memory, anticipation, etc) out of the clock experiment as much as possible and see what the result is. Instead of directly observing the passing clock, an observer (Bx) in rest frame (B) is in an enclosed structure and is viewing the passing clock on a screen via a live feed from a movie camera mounted on the structure (same rest frame as the observer). The camera is computer controlled and masks everything out of the picture other than the clock. The camera also zooms in and out as the clock passes to keep it at the same size when observed by (Bx). Essentially (Bx) would observe the clock as if it was being observed from rest frame (A). The clock wouldn’t appear to be moving sideways and the ball wouldn’t appear to be moving in a zigzag manner.

Exactly.
Yes, B would observe the clock as if it was being observed from reference frame of A. Why? Well, look at waht you are doing...
Your scenario is exactly the same as if A had taken the video, so no wonder it appears as it would from the POV of A. It is the POV of A. Effectively, the POV of A is being captured on film and shown to B.

 

[ynot]

Yes trying to mix concepts born from the interpretation of Quantum Mechanics in Relativity is common. In a sense the change in perspective in Relativity is like the rubber pencils trick. The difference being that the pencil trick is due to a limited visual processing speed. Relativity defines a limited speed of information of reality. Try another perception experiment. Drop a small but heavy rock from a moving car. You will see that except for wind resistance the rock appears to drop straight down. However to the person standing by the road the rock appears to fall at an angle. It is no different in Relativity with your tube.

The big difference with Relativity is that what is space for one person can be time for another. This is not because space actually becomes something different (time) but because space is defined by the time it takes to move through it. In the relativity of rigidity it can appear that solid objects bend etc. The end result is nonetheless exactly what you would expect without relativity (like the pencil). The caveat being that separate clocks at different points on the object may not agree on how long it took. No need for separate realities when the changes in relative time completely defines the whole thing

The rock only exists in its own rest frame and falls in a straight line toward the force of gravity when dropped. That it is perceived to be moving on an angle when observed from another rest frame is an illusion. To use the movie analogy used earlier, the single event is being separated in to a strip of many events and this creates the illusion.

 

[PixyMisa]

If that was what was being claimed by Relativity there would be no problem (for me). It seems to me however that Relativity is claiming that a different frame observation of the clock is creating a different reality of the clock. It’s not said that the clock seems to be running slower, it is said that it is running slower

Well, the point is, there's no absolute "is" - no preferred frame of reference. There's just what you observe. You observe the clock running slower, so for you, the clock is running slower. It's the same clock, as viewed by two different observers.

 

[PixyMisa]

The rock only exists in its own rest frame and falls in a straight line toward the force of gravity when dropped.

Frames of reference aren't real. They're mathematical constructs.

What's more, the rock doesn't move relative to its own rest frame. The Earth moves.

That it is perceived to be moving on an angle when observed from another rest frame is an illusion.

Not an illusion; a perfectly accurate and correct observation from another frame of reference.

 

[ynot]

First of all, observations don't create anything. All the inertial systems exist independenly of physical observers. (This isn't something that can be explained very well without going into the mathematics).

That is exactly what I’m saying. As I understand it, Relativity is saying something different

The clock is running slower in the other frame, but this doesn't mean that we're talking about two different "realities". We're just talking about two different points of view. Think of a cylinder for example. Viewed from the top, it looks like a circle. Viewed from the side it looks like a rectangle. But it's still just one object. We just can't see the whole thing just by looking at it from one direction.

Here is the crux of the (my) problem! You say the clock “is” running slower when observed from the other frame. In other words the clock is actually simultaneously running both correctly and slower. Surely this is claiming two realities of the same clock. We're not “just talking about two different points of view”. You’re saying that, viewed from the other frame, the clock has a different reality. If you were saying that it was perceived to be running slower, I would quickly agree. I don’t think that the cylinder example is valid comparison. The shape of the silhouette of the cylinder changes when viewed from different an angles, but the time shown face of the clock doesn’t

 

[ynot]

How it acts is different depending on what frame of reference you are observing it from.
.

I think that should be how it appears or is percieved to act. How it actually acts at its most local level is the reality. Not how it appears from the frame of reference you are observing it from

Yes, B would observe the clock as if it was being observed from reference frame of A. Why? Well, look at waht you are doing...
Your scenario is exactly the same as if A had taken the video, so no wonder it appears as it would from the POV of A. It is the POV of A. Effectively, the POV of A is being captured on film and shown to B.

The observation is essentially the same but the scenario is different. The camera is observing from the frame of the person, not from the frame of the clock. The camera is making the same observation that the observer would, but it is able to filter out factors that cause the illusion.

 

[ynot]

Frames of reference aren't real. They're mathematical constructs.

What's more, the rock doesn't move relative to its own rest frame. The Earth moves.

I didn’t say that he rock moves relative to its own rest frame. I said it moves within it’s own rest frame. Actually it doesn’t, it’s accelerating to another rest frame. Given that everything is constantly moving relative to everything else at an atomic level, a true rest frame is impossible. Or perhaps only possible for the smallest possible particle.

Not an illusion; a perfectly accurate and correct observation from another frame of reference.

Perhaps illusion is not a good word to use. A perfectly accurate and correct observation from another frame of reference I agree, but not a perfectly accurate and correct observation of the actual event as it actually occured at it’s most local level.