Jump to content
michel123456

michel123456's relativity thread (from Time dilation dependence on direction)

Recommended Posts

45 minutes ago, The victorious truther said:

In the description is declares that it's a row of dice moving. Not a single (die) pictured at different times while it was moving if I recall correctly. 

My mistake. The questions are still focusing on irrelevant details, given the fundamental misunderstanding of relativity.

 

Share this post


Link to post
Share on other sites
26 minutes ago, swansont said:

My mistake. The questions are still focusing on irrelevant details, given the fundamental misunderstanding of relativity.

That's fine. . . simple mistakes pail in comparison to those regarding our fundamentals. 

Share this post


Link to post
Share on other sites
9 hours ago, michel123456 said:

Quest1. Why is the distance d2 larger than the distance d1? Shouldn't it be contracted?

It is, see image (b). Image (c) is what the dice look like when you receive (at the same time) light that left the dice at different times and traveled different distances. Image (b) is what you see if you remove the differences due to delay of light.

In fact, if you put points of light all over the dice and sync'd them to flash at a single moment in the observer's frame, what you see would look exactly like (b). This assumes persistence of vision or exposure time somewhat proportional to d2, since the light wouldn't all arrive at the same time.

You could figure out so many mysteries if you learned SR.

1 hour ago, swansont said:

Is the “length” moving? No. So it’s not contracted.

Do you mean the lengths between the dice? Those lengths are contracted, see (b).

Here's a thought experiment to show that the spaces between objects are contracted the same as objects themselves: Consider the dice in their rest frame. Put an enclosure around each die, and connect them with sticks. In the moving frame, everything contracts, and the dice never leave the enclosures. The distance between the dice must contract the same as an object of the same length.

Edit: After catching up to the rest of the conversation I see my explanation isn't necessary. I think that if you showed the dice say 1s apart (big dice) in a Newtonian frame I guess??? in (a), and showed them "at the same events" 1/gamma s apart in (b), it would look the same as it does now. If (b) showed them 1s apart in the new frame, they'd be spaced farther.

Edited by md65536

Share this post


Link to post
Share on other sites
2 minutes ago, md65536 said:

Do you mean the lengths between the dice? Those lengths are contracted, see (b).

I based this on my misunderstanding that these were snapshots of one die. See above.

 

Share this post


Link to post
Share on other sites
33 minutes ago, md65536 said:

It is, see image (b). Image (c) is what the dice look like when you receive (at the same time) light that left the dice at different times and traveled different distances.

That is highly confusing, I assumed the dices were equidistant. Thanks for the explanation.

17 hours ago, joigus said:

Time for the free falling trajectory is actually a maximum, not a minimum.

Unintuitive? Perhaps, but that's the way it is.

I was still thinking about this statement, when I agree too quickly it means I haven't think enough.☺️ The frequency equation gives results clocks ticking slower but also faster than normal. In Janus example, with 0.8c, the clock that goes away ticks at 0.3 rate, and the returning clock ticks at rate 3. As seen from the observer at rest, this clock ages faster. So, why do you say that time for the free falling trajectory is a maximum?

Share this post


Link to post
Share on other sites
14 minutes ago, michel123456 said:

[...]

I was still thinking about this statement, when I agree too quickly it means I haven't think enough.☺️ The frequency equation gives results clocks ticking slower but also faster than normal. In Janus example, with 0.8c, the clock that goes away ticks at 0.3 rate, and the returning clock ticks at rate 3. As seen from the observer at rest, this clock ages faster. So, why do you say that time for the free falling trajectory is a maximum?

Geodesics are obtained by minimizing the action. The action in relativity is proportional to proper time. Geodesics correspond to inertial observers.

Proper time is maximum instead of minimum. Action in physics is stationary, rather than minimum really, so the positive-negative character is not so clear. AAMOF, action across different physical theories typically is a saddle point. In relativity it's a maximum instead of a minimum because of hyperbolic geometry (I think it's all in the hyperbolic geometry of space time). Action must always be stationary, but not necessarily positive definite. And in relativity it's not.

7 minutes ago, Charles 3781 said:

I offer this thought, in all humility - if Special Relativity theory can generate the above 6 long, complicated pages of debate among highly intelligent people,  without their being able to reach any agreement about what it actually means, as appears to be the case -  could this be because the theory isn't right?

It's rather a two-sided debate. Basically @michel123456 vs everyone else. Among the rest, the only debate I see is how to find the argument that clinches the case and doesn't end up in Michel spending another 20 years doubting relativity.

2 hours ago, michel123456 said:

I was still thinking about this statement, when I agree too quickly it means I haven't think enough.☺️

You don't strike me as someone who agrees too quickly on anything. ;)

Whenever you agree, I brace myself. ;)

Share this post


Link to post
Share on other sites
1 hour ago, joigus said:

You don't strike me as someone who agrees too quickly on anything. ;)

You got me.

1 hour ago, joigus said:

Michel spending another 20 years doubting relativity.

1.I hope I have that much.

2. Again, Relativity is OK to me as long it is considered as a Theory that describes (between others) a phenomena comparable to perspective: a kind of effect caused by the different states of motion of different observers, a Theory that explains how one observer can relate his observation to another observer. Taking the example of length contraction, it seems evident (to all of us I hope) that once the traveler stops, the resting observer does not observe length contraction anymore,  the phenomena has vanished. In fact, in his own FOR, the traveler was never contracted at all: length contraction is an observational effect that appears from the FOR of reference (at rest). Exactly as the forearm presented in perspective: it does not change length. Is this doubting of Relativity?

Share this post


Link to post
Share on other sites

IMO, fields are the tipping point. When you review a handful of examples with Alice and Bob, the twins, the car getting in the garage, etc., it's all very useful, it's very illuminating. But somebody will always come around and tell you, "what about a guy with a flashlight traveling on a spaceship..." and so on, presenting you with a new "paradox."

Studying relativistic fields really makes you give up on trying to find either mechanical explanations, or counterexamples. Thought experiments, or gedankens, are not the reason Einstein came up with relativity. It was field theory. And then he devised some of these impressively clever ways to reason it out. The tipping point for him were Maxwell's equations for the electromagnetic field. Everything else must comply with it. You think about the paradoxes very carefully and some argument always saves the day for Einstein.

In the twins' paradox example, it would be really complicated to calculate how much time the non-inertial twin rejuvenates in doing the trip. The spirit of the argument is not in the calculation really. It's in the concept. You immediately say "doh!"

So it's the other way around, really. It's like Darwin's theory. Some people never get it. This theory must be true. The arguments are so compelling. Different organisms produce almost equal offspring organisms. The external conditions change much more slowly than the cycle of reproduction, so to speak. Some differences will be maintained; others will disappear. Now let's explain why different protists have different layerings of membranes. And Darwin's theory gives you the right line of reasoning. Aren't you convinced? Do an experiment. And the results always confirm the theory. Same in relativity. Only in relativity it's so much easier to do an experiment.

Eise told you about muons lasting longer when they move fast, for example. How else do you explain that? I think the time has come to call you to task and challenge you to come up with a better explanation for that than time dilation, which has been checked to extraordinary precision.

And that really is my two cents.

2 hours ago, joigus said:

Geodesics are obtained by minimizing the action.

I meant: Geodesics are obtained by making the action stationary (doesn't matter if they're maxima or minima; they happen to be maxima).

Share this post


Link to post
Share on other sites
1 hour ago, michel123456 said:

You got me.

1.I hope I have that much.

2. Again, Relativity is OK to me as long it is considered as a Theory that describes (between others) a phenomena comparable to perspective: a kind of effect caused by the different states of motion of different observers, a Theory that explains how one observer can relate his observation to another observer. Taking the example of length contraction, it seems evident (to all of us I hope) that once the traveler stops, the resting observer does not observe length contraction anymore,  the phenomena has vanished.

Yes

Quote

In fact, in his own FOR, the traveler was never contracted at all: length contraction is an observational effect that appears from the FOR of reference (at rest). Exactly as the forearm presented in perspective: it does not change length. Is this doubting of Relativity?

No, it is not an “observational effect” Yes, this is doubting/denying relativity.

While moving, the object is length contracted to any observer in another frame. If it undergoes an interaction that depends on its shape, like a nucleus and electromagnetic and nuclear interactions, those interactions are such that the nucleus is length contracted. If you assume the nucleus is spherical (or whatever shape it has at rest) you get the wrong answer. The effects from electric and magnetic fields of moving particles only give correct answers if you account for the length contraction. Also the muon decay mentioned by Eise, that you have avoided addressing. All confirmed by experiment.

Similarly, moving clocks run at a different rate than while at rest, and as a result, will disagree with a clock that remained at rest. And again, we have done the experiment. This actually happens.

18 minutes ago, joigus said:

IMO, fields are the tipping point.

That would require maths. 

Share this post


Link to post
Share on other sites
2 hours ago, swansont said:

That would require maths. 

I know. It's out of the question.

3 hours ago, michel123456 said:

2. Again, Relativity is OK to me as long it is considered as a Theory that describes (between others) a phenomena comparable to perspective: a kind of effect caused by the different states of motion of different observers, a Theory that explains how one observer can relate his observation to another observer.

Let me give offer you an analogy of why foreshortening is not as inconsequential as you seem to think. You try to get a very long slab of wood into a garage. If you introduce it with its length (analogue of proper time or proper length) perpendicular to the garage's door baseline, so to speak, it doesn't fit. But if you foreshorten it by rotating it, it does fit. Picture yourself inside the garage helping others to get it inside. You may even close one eye so you don't have parallax errors and you can more precisely estimate the foreshortening. The slab has "shortened", and you know it's safe to push it in.

So foreshortening has real consequences.

If you "rotate" muons in space time with hyperbolic angle v/c, they last long enough that they can reach you from the ionosphere. If they were at rest, they wouldn't "fit." (In this case they would be too "short", they wouldn't last long enough.)

I hope that helps. Analogies sometimes help.

Edited by joigus

Share this post


Link to post
Share on other sites
9 hours ago, joigus said:

I offer this thought, in all humility - if Special Relativity theory can generate the above 6 long, complicated pages of debate among highly intelligent people,  without their being able to reach any agreement about what it actually means, as appears to be the case -  could this be because the theory isn't right?

A theory such as special relativity or general relativity can be a successful well understood mathematical/theoretical and applied theory of how the world works. Yet we could still disagree on philosophical interpretations of the relationship of our naive realism and previous theories with their accompanying previous ontologies to this specific theory (as well as fully interpreting the theory itself). Take the discussion of proper mass and relativistic mass and ask the legitimate question of whether one/both/neither of these newer concepts in special relativity would match up intuitively/ontologically (philosophically) to the classical physics concept of inertia (mass). Is relativistic mass the relativistic counterpart to inertia or is this a false comparison? This is a legitimate question but it doesn't really come to much difficulty when it comes to actually applying said theory if you had a case to make that we applied it, expected a certain result but got the wrong one, but under a different interpretation the experimental results could be construed to be correct then i'd agree there is something contentious. . . i'll await for you to actually propose this. 

In the history and philosophy of physics the discussion of what forces are as well as whether we should even accept action-at-a-distance ones wasn't settled with Newtons Principia but this philosophical side discussion didn't stop us from applying successfully the mathematical results there in for generations. 

7 hours ago, michel123456 said:

1.I hope I have that much

You just said your biased. . . 

7 hours ago, michel123456 said:

2. Again, Relativity is OK to me as long it is considered as a Theory that describes (between others) a phenomena comparable to perspective: a kind of effect caused by the different states of motion of different observers, a Theory that explains how one observer can relate his observation to another observer.

Which is technically what the GALILEAN transformation already did in CLASSICAL physics but I do not see you screaming at the top of lungs about that and how it must be a perspective thing. Classical physics did the same thing of relating certain quantities in one frame of reference to that of another but they were no less real with respect to those frames of reference. 

7 hours ago, michel123456 said:

Taking the example of length contraction, it seems evident (to all of us I hope) that once the traveler stops, the resting observer does not observe length contraction anymore,  the phenomena has vanished.

Be careful with your language here. . . novice. . . when you say STOP it's implied you mean non-inertially accelerate or change reference frames so that they entered the specific one in question. Obviously if we go to classical physics in which a person who was moving with respect to our frame of reference then suddenly de-accelerate to enter our frame of reference. . . they aren't moving any more. . . cause they stopped with respect to our frame of reference. . . so if you ask whether the non-moving observer is moving then clearly no. . . because they aren't moving. To be length contracted or appear as such from other frames of reference the object in question would have to be moving. 

7 hours ago, michel123456 said:

In fact, in his own FOR, the traveler was never contracted at all: length contraction is an observational effect that appears from the FOR of reference (at rest). Exactly as the forearm presented in perspective: it does not change length. Is this doubting of Relativity?

Velocity is a real effect. . . but it's frame dependent on whether it arises and you won't see the same thing from every frame of reference nor could you claim that one particular velocity was more real or not or even declare that he is actually at rest when in other frames of reference he is moving. If this was purely a perceptual effect then we would think this wouldn't be accompanied by clear dynamical and kinematical issues involved with taking measurements. . . course you could mathematically reproduce this understanding with a classical theory of literal length contraction (as well as a counterpart one with no length contraction but finite speed of perceptual effects) and compare. . . to you know. . . show who is right. 

 

Share this post


Link to post
Share on other sites
33 minutes ago, The victorious truther said:

Velocity is a real effect

Just to add to what has been said already - velocity (or better: it's magnitude, being speed) isn't something that any one observer "has", it's a relationship between two frames in spacetime. What's more, this relationship is of a geometric nature - using the concept of what is called rapidity, speed is actually equivalent to a rotation angle.

So in that sense, @michel123456 does have a point - SR is all about perspectives. But these perspectives aren't optical/visual ones, and they aren't purely spatial ones either. When I talk about rotations above, then those aren't rotations in Euclidean space, but in a 4D hyperbolic spacetime. So we rotate from space to time, and vice versa. That's exactly what a Lorentz transformation is - a hyperbolic rotation in spacetime, so inertial observers in relative motion are related by a rotation in spacetime. This is why their measurements of space and time, taken separately, do not necessarily agree. But it is important to understand that this is physically real, it isn't just a matter of visual appearance; it has real physical consequences, which can be directly observed and measured. 

Share this post


Link to post
Share on other sites
8 hours ago, joigus said:

If you introduce it with its length (analogue of proper time or proper length) perpendicular to the garage's door baseline,

Always when I'm sleepy I make mistakes like this. I meant, of course, "if you introduce it with its length parallel to the garage's door baseline." :doh:

And @The victorious truther, you misquoted me.

Share this post


Link to post
Share on other sites
11 hours ago, michel123456 said:

In fact, in his own FOR, the traveler was never contracted at all: length contraction is an observational effect that appears from the FOR of reference (at rest).

As others also notice: you are consistently avoiding to explain from your view why muons make it to the surface of the earth. It is time you take the challenge.

Another remark (which might help you with the 'muon-challenge'): you assert that in the so called 'twin paradox', there is an asymmetry, because the effect of the time dilation stays (the traveler has not grown older so much as the home-stayer), but the length contraction has gone (the twins are still equally sized). Truth is that you comparison is wrong. After arriving back home the twin's clocks tick at the same rate, so the time dilation itself is gone, just as the length contraction. However this is not true during the travelling: the length contraction of the length of the trip for the traveler is real, and its 'mirror' for the home-stayer is the real time dilation. As space and time are relative, but spacetime is not, this is no problem at all. Important is that the twins agree on their observations when they are in the same FOR again: they agree that the traveling twin has not aged so much as the home-stayer twin. So they live in the same reality.

Edited by Eise

Share this post


Link to post
Share on other sites
2 hours ago, Markus Hanke said:

So in that sense, @michel123456 does have a point - SR is all about perspectives. But these perspectives aren't optical/visual ones, and they aren't purely spatial ones either. When I talk about rotations above, then those aren't rotations in Euclidean space, but in a 4D hyperbolic spacetime. So we rotate from space to time, and vice versa. That's exactly what a Lorentz transformation is - a hyperbolic rotation in spacetime, so inertial observers in relative motion are related by a rotation in spacetime. This is why their measurements of space and time, taken separately, do not necessarily agree.

Exactly. Whether foreshortening is real or not is quite immaterial a discussion to me. My example of the garage was meant to illustrate that foreshortening is "real" enough to anyone interested in getting a slab of wood inside a garage.

Share this post


Link to post
Share on other sites
1 hour ago, Eise said:

After arriving back home the twin's clocks tick at the same rate, so the time dilation itself is gone, just as the length contraction.

Good point. Also, a die, or a slab, or a person, all have some proper length, width and height, Lx, Ly, Lz, but they don't have a "proper time extension", T. In elementary relativistic discussions objects can be considered to have an instantaneous presence, so to speak. They are time-pointlike. That's why the treatment is not completely symmetric in space and time. 

From the POV of integrated, or elapsed, or covered time and/or space:

The twins differ in the proper time elapsed for each of them. But if you try to find an analogue of that in space (the proper length covered, integrated to the whole respective paths), you find it's always zero for both of them, because with respect to themselves, they haven't moved. You can be always at x=0, y=0, z=0. But you cannot keep at t=0. This question has arisen before.

You always are moving in the time direction, unless you are a photon.

Share this post


Link to post
Share on other sites
4 hours ago, Eise said:

As others also notice: you are consistently avoiding to explain from your view why muons make it to the surface of the earth. It is time you take the challenge.

Another remark (which might help you with the 'muon-challenge'): you assert that in the so called 'twin paradox', there is an asymmetry, because the effect of the time dilation stays (the traveler has not grown older so much as the home-stayer), but the length contraction has gone (the twins are still equally sized). Truth is that you comparison is wrong. After arriving back home the twin's clocks tick at the same rate, so the time dilation itself is gone, just as the length contraction. However this is not true during the travelling: the length contraction of the length of the trip for the traveler is real, and its 'mirror' for the home-stayer is the real time dilation. As space and time are relative, but spacetime is not, this is no problem at all. Important is that the twins agree on their observations when they are in the same FOR again: they agree that the traveling twin has not aged so much as the home-stayer twin. So they live in the same reality.

But What the trveler twin is observing? he is observing that the guy at rest is older. How is that possible?

Share this post


Link to post
Share on other sites
1 hour ago, michel123456 said:

But What the trveler twin is observing? he is observing that the guy at rest is older. How is that possible?

I can't even guess how many times you have asked that question and how many times it has been answered.  But I think I get it now.  Your ultimate 'truth' is your intuition and what you see with your eyes.  If an answer conflicts with your intuition, then it must be wrong. 

You keep asking the same questions over and over because you are waiting for an answer that agrees with your intuition.  Sorry to say that you will never get that answer because your intuition is wrong.  Everyones intuition is wrong, at low speeds it does appear that velocities can be added by straight addition, but that is quite simply not true. 

I'm afraid you're destined to continue to ask the exact same questions that you have been asking for the last 20 years.  What a waste of time and effort.

Share this post


Link to post
Share on other sites
24 minutes ago, Bufofrog said:

I can't even guess how many times you have asked that question and how many times it has been answered.  But I think I get it now.  Your ultimate 'truth' is your intuition and what you see with your eyes.  If an answer conflicts with your intuition, then it must be wrong. 

You keep asking the same questions over and over because you are waiting for an answer that agrees with your intuition.  Sorry to say that you will never get that answer because your intuition is wrong.  Everyones intuition is wrong, at low speeds it does appear that velocities can be added by straight addition, but that is quite simply not true. 

I'm afraid you're destined to continue to ask the exact same questions that you have been asking for the last 20 years.  What a waste of time and effort.

First rule of physics: leave intuition at home. :)

Share this post


Link to post
Share on other sites
6 hours ago, joigus said:

And @The victorious truther, you misquoted me.

I must supremely apologize then. I must have missed some important context involved when I abruptly popped in here. 

6 hours ago, Eise said:

As space and time are relative, but spacetime is not, this is no problem at all.

Stated differently there is no relativity principle for non-inertial frames of reference in classical or relativistic physics. 

Share this post


Link to post
Share on other sites
3 minutes ago, The victorious truther said:

I must supremely apologize then. I must have missed some important context involved when I abruptly popped in here. 

It's not that bad. Your apologies are accepted, and they didn't have to be supreme. You just missed some aspects of the interface:

 
Quote

 

  19 hours ago, joigus said:

I offer this thought, in all humility - if Special Relativity theory can generate the above 6 long, complicated pages of debate among highly intelligent people,  without their being able to reach any agreement about what it actually means, as appears to be the case -  could this be because the theory isn't right?

 

 

I didn't say that. You did. :D 

Share this post


Link to post
Share on other sites
2 hours ago, michel123456 said:

But What the trveler twin is observing? he is observing that the guy at rest is older. How is that possible?

Because both twins agree that the world line of the travelling twin is shorter than that of the stationary twin (one reality!). A purely inertial frame always represents the longest possible world line between two given events - since the travelling twin is not purely inertial, his world line will be shorter, so he ages less in comparison.

Edited by Markus Hanke

Share this post


Link to post
Share on other sites
!

Moderator Note

After some staff discussion, we have decided that this thread is now the only place where michel123456 may discuss topics related to time and relativity. As such it has been split from the parent thread and placed in speculations.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.