Is a length contraction just a visual thing?

[The God]

Absolute Space..

Few here know the maths of transformation and they will prove length contraction. But try it this way spacetime expands and with that wavelength also, spacetime curves and with that light bends. So if light bends or expands or contracts then it is natural that other things cannot hold on and must bend, contract and expand.

take this as about distance measurement in spacetime in a moving frame.....that mathematically has to contract to keep 'c' intact...everyone here knows that it is not some kind of speed dependent elastic contraction which you are trying to push.. But none here wish to take a position contrary to SR, they are flowing without understanding and with doubts hidden and supressed for fear of getting termed as cranks....

 

[paddoboy]

Absolute Space..

Few here know the maths of transformation and they will prove length contraction. But try it this way spacetime expands and with that wavelength also, spacetime curves and with that light bends. So if light bends or expands or contracts then it is natural that other things cannot hold on and must bend, contract and expand.

take this as about distance measurement in spacetime in a moving frame.....that mathematically has to contract to keep 'c' intact...everyone here knows that it is not some kind of speed dependent elastic contraction which you are trying to push.. But none here wish to take a position contrary to SR, they are flowing without understanding and with doubts hidden and supressed for fear of getting termed as cranks....

Length contraction takes place and is real.....The evidence to support that has been given.
Time dilation is also real and also evidenced.
Any claims you have to the contrary about any aspect of SR/GR or standard accepted cosmology, which you cannot support is baseless and without credibility. That is fact.
You of course presumably do not have credentials in the field of cosmology, and as such although you are within your rights to say what you like, your expectations that it be taken seriously is in question.

 

[The God]

Length contraction takes place and is real.....The evidence to support that has been given.
Time dilation is also real and also evidenced.
Any claims you have to the contrary about any aspect of SR/GR or standard accepted cosmology, which you cannot support is baseless and without credibility. That is fact.
You of course presumably do not have credentials in the field of cosmology, and as such although you are within your rights to say what you like, your expectations that it be taken seriously is in question.

Paddoboy,

As soon as you push physical and real contraction, then things become dicey and causes many other physics based issues, thats why relativity creates notorious paradoxes. I am sorry, Paddoboy, you are an unskilled torch bearer of relativity, your responses are mostly, it is proved and it is done by MIT etc and those guys have considered all; these all are faith based not your individual education based.

 

[brucep]

Really? You are refusing to accept the clear and convincing evidence? Gee, I didn't see that coming.

I certainly am bored with this waste of time. Bu-bye.

Different handle same dude. Deja vu all over again.

 

[paddoboy]

Paddoboy,

As soon as you push physical and real contraction, then things become dicey and causes many other physics based issues, thats why relativity creates notorious paradoxes. I am sorry, Paddoboy, you are an unskilled torch bearer of relativity, your responses are mostly, it is proved and it is done by MIT etc and those guys have considered all; these all are faith based not your individual education based.

That's OK, It means I'm carrying the torch for physics and cosmology that has already run the gauntlet and passed peer review as well as all tests thrown at it.
You of course appear to be the torch bearer for the religiously inspired who have seen their deity pushed into near oblivion and that eats at their craw, does it not?
Yes, length contraction is real, just as time dilation is real, and all FoR's being as valid as each other: That's relativity, that's science, that's logic, and that's what has passed review.
Which leaves you in never never land...sorry about that

 

[brucep]

Paddoboy,

As soon as you push physical and real contraction, then things become dicey and causes many other physics based issues, thats why relativity creates notorious paradoxes. I am sorry, Paddoboy, you are an unskilled torch bearer of relativity, your responses are mostly, it is proved and it is done by MIT etc and those guys have considered all; these all are faith based not your individual education based.

They're are no paradox in relativity. You're a liar. Prove your not.

 

[paddoboy]

Different handle same dude. Deja vu all over again.

From where I sit it appears there is now a concerted effort to desperately try and reflect a general scenario of disquiet and dissatisfaction, and a lack of confidence in SR/GR and portray it to being a troubled, incomplete, problematic, theory/s, with anomalies galore. One of them has already claimed that GP-B was a put up job....that the Eddington experiment was flawed....that recent gravitational wave discoveries is a conspiracy....that science is one giant conspiracy: And then expect that they are making a difference for their religiously driven agendas: Unable to see that they are confined on a fart arse science forum, never to be heard of again, never to make a difference, and wallowing within their own inflated egos. Sad.

 

[brucep]

From where I sit it appears there is now a concerted effort to desperately try and reflect a general scenario of disquiet and dissatisfaction, and a lack of confidence in SR/GR and portray it to being a troubled, incomplete, problematic, theory/s, with anomalies galore. One of them has already claimed that GP-B was a put up job....that the Eddington experiment was flawed....that recent gravitational wave discoveries is a conspiracy....that science is one giant conspiracy: And then expect that they are making a difference for their religiously driven agendas: Unable to see that they are confined on a fart arse science forum, never to be heard of again, never to make a difference, and wallowing within their own inflated egos. Sad.

For sure but I meant it literally not figuratively. LOL. Figuratively they're all the same dude anyway. LOL.

 

[absolute-space]

I like your attitude, absolute_space. Two reference frames are invariant: one (at rest, <c) for bound energy or matter, and one (=c) for unbound energy.

I have told you that Lorentz contracted lengths are equivalent to Doppler shifts, and as usual, everyone simply ignores this:

http://physics.nist.gov/cuu/Units/meter.html

"The 1889 definition of the meter, based upon the artifact international prototype of platinum-iridium, was replaced by the CGPM in 1960 using a definition based upon a wavelength of krypton-86 radiation. This definition was adopted in order to reduce the uncertainty with which the meter may be realized. In turn, to further reduce the uncertainty, in 1983 the CGPM replaced this latter definition by the following definition:

• 
  The meter is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second."

But there is nothing magical about the selection of a krypton-86 atom for our standard meter length other than convenience. We could replace the standard with a number of wavelengths of a LASER CAVITY.

Assume a ONE meter length laser cavity that is in a frame moving ENDWISE at relativistic speed with respect to a frame at rest. Both ends of the cavity are half-silvered, so that laser light can escape either end. As the cavity approaches, the wavelength of the laser cavity is BLUE SHIFTED. When the laser cavity passes the point at which the observer at rest is standing, it will appear RED SHIFTED. To determine how long the laser cavity was, YOU SIMPLY AVERAGE the BLUE, RED shifted frequencies to find their frequency in the REST FRAME.

You have also clocked the speed of the moving laser cavity as it passed your position (<c) with a chirped laser speed gun. TO FIND WHETHER OR NOT THE LORENTZ CONTRACTION VIEWED IS "REAL" OR NOT, YOU SIMPLY APPLY THE LORENTZ TRANSFORMATIONS OF LENGTH AND TIME FOR THE VELOCITY MEASURED WITH THE SPEED GUN AND ASSUME THE SPEED OF LIGHT WILL BE INVARIANT (MEASURE THE SAME) IN THE MOVING FRAME AS IT DOES IN THE REST FRAME. No preferred FoRs here.

Is length contraction "real?". YES. Is time dilation "real?". YES. Is there a "preferred" reference frame? Actually there are TWO INVARIANT reference frames here: "AT REST" for bound energy (matter), and "MOVING AT C" for unbound energy, such as photons. Both of these frames must be defined and exist in order for the speed of light to be invariant at all, because if something moves (even a photon), it must move RELATIVE to something else. However there is no preferred frames in terms of the moving, at rest laser cavity. If the rest frame had a stationary laser cavity of the same design, the same calculations of length contraction and time dilation, as well as respective Doppler shifts would apply to measurements made from the moving frame. The situations are symmetrical with respect to each other, as you might expect.

But there is no equivalent of an absolute position for the laser cavity that both observers can simultaneously agree on, nor an absolute instant that is an origin for temporal coordinates. That being the case, the whole idea of an INTERVAL based on vector additions of absolute positions in higher order Euclidean spaces as something invariant is ludicrous.

Be that as it may, there is no such thing as an absolute position or an absolute origin of an absolute position, other than the geometric centers of bound particles of energy that is matter, and none of those absolute positions are really absolute in terms of anything other than the positions of other such particles that are in the same rest frame, which is almost never the case.

A fixed origin attached to inertialess empty space is simply a deranged mathematical fantasy, and it doesn't matter who does it or for what reason. Whenever a mathematician is asked to specify from which end (or from the center) a Lorentz contracted length a meter stick or our laser cavity contracts, they invariably toss out a mathematical convention that has no justification or basis in mathematics, physics, or anything else. If there is not a convention for this, how can there possibly be a convention relating to whether a selected origin of a coordinate system in space is "off" by ± an arbitrary contracted length l? There isn't. There can't be.

So if you were confused at the beginning of this thread, now you really should be scratching your head and saying something like "what the?". This much is a normal reaction.

Enjoy and embrace the confusion. It's actually much better than the alternative.

Thank you for your informative post.

 

[absolute-space]

It can be helpful to think of length contraction as analogous to a rotation.

Stand next to an object - let's use a car - and look at it from a particular angle. Now walk around it. You'll notice that the car looks different as you walk around it.

Somebody skeptical about the reality of rotation might well ask "Is the rotation of the car a real effect, or just a visual thing?"

It seems that a particular observer's view of the car can be affected in two different ways. One way is to do something to the observer (like having them walk around the car). The other way is to do something to the car (like putting it on a turntable and rotating the table). The observer's visual perception of the car is the same in each case.

Consider somebody sitting inside the car. They look out the window and see the person who is watching from outside apparently rotating around the car. They might wonder - what is "really" rotating? It is the car, with them in it, or the outside observer? The visual effect is the same.

Length contraction is not much different from this. It has something to do with relative motion between an observer and an object of some kind. Is it real? Well, it's an observable effect. Is rotation real? It, too, is an observable effect.

I agree it is a real visual effect. When the observer moves around the car, the light angles change from all points of the car relative to the observer, the further away point of the car has a longer length of light and space-time between their eyes and point source. The shorter distance of the angle away has a shorter length of light and space-time between their eyes and observer. When the car is in motion and a relatively stationary observer observers the car passing, the observer , observes a narrower field of light by the relative velocity of the car and angle of the reflected light. We have to consider the affect of distance relative to, two observers.

The effect being caused by the inverse square law and the radial of light diminishing, and the visual scaling of distance having a visual volume contraction relative to two bodies. resulting in an observation of N-dimensional space.

 

[danshawen]

It can be helpful to think of length contraction as analogous to a rotation.

No it isn't. However, Minkowski was "sort of" on the right track about one thing. A "rotation" of unbound energy is another mode of propagation of energy, in fact, the ONLY other mode of propagation, other than in a straight line at c. There is a deep relationship between the two modes of propagation of energy, but it isn't even close to the kind of physical rotation Minkowski proposed. Rotation relative to what? With what point as the origin or center of rotation? Which direction is the rotation, in 3D, 4D or otherwise? Gotcha again. And again.

Minkowski rotation is not physically either real or meaningful in connection with the relationships between length contractions and time dilations, in four dimensions or otherwise. It has the flaw of treating time as though it were physically spatial in terms of a rotation AND as a physical length that is somehow rotating in both 3 and in 4 dimensions, without adequately explaining either. He seems unable to decide whether bound energy is the same physical thing as energy propagating a c. It is. Since E=mc^2.

Every physical dimension in this universe in every direction is light travel time, not some mangled Pythagorean complex expression of physical lengths commingled with time. Our current standards of length are based on the simple fact of the identity of space with light travel time. If they were not, one would expect there to be a "standard" for rotation to go along with standards of length. If "at rest" has no rotation, then neither does any other reference frame. Contraction is real. Rotation isn't. This simple fact is the reason that the empty spaces between atoms are physically no more substantial (although distinctly different) than Doppler shifts, and Minkowski never suggested that Doppler shifts were rotations. Why not? Most mathematicians get their minds tangled into knots tighter than physical ones when trying to get a handle on this. It's the reason that Bell's Theorem doesn't apply both to QM and SR simultaneously. I'm not sure it really applies to either, and I don't care.

It, too (Minkowski rotation), is an observable effect.

No it isn't. If you are referring to applications to critical mass cross sections, for example, this geometry doesn't actually work. It doesn't work for any application. Not that anyone involved in such activities would even be able to tell you how badly it fails. It's classified, and they are bound by non-disclosure and other agreements designed to make certain that no one else is let in on the secret. I'm not. I'm telling you, Minkowski rotations applied to Lorentz covariance and the Interval used to derive them is so much mathematical trash. No energy transfer event that is not entangled or the same event in this universe is "simultaneous" in the way Minkowski conceived it. Time is very much grainier than the propagation of unbound energy at c in a straight line. It is the quantum field which can transfer energy between rotational (bound) and linear (unbound) propagation modes that is the key to understanding this.

The moment a mathematician tries to "plant" the origin of an absolute space into inertialess relativistic space, or even non-static Euclidean dimension of higher order Hilbert spaces, the results of any subsequent calculation based on solid geometry will be as flawed as they are needlessly tortured by an insistence of calculating dynamics based on a static model of geometry. This is the principle reason why relativity doesn't "play nice" or "get along" with geometry, the topology of a sigma field, in quantum mechanics, quantum field theory, or anything else. The only reason General Relativity works like solid geometry at all is that until VERY RECENTLY it has mostly dealt exclusively with interaction of bound energy that is matter. As such, it is a SLOW process being described, not FASTER ones involving interaction with unbound energy traveling at c.

Wheeler's derivation of the LT for Special Relativity using a photon trapped between mirrors (like our laser cavity) is wrong. The photons are trapped simply because for as long as they are reflected from the electrons on the surfaces of the cavity mirrors, it shares the inertia of the spacecraft. The endwise laser cavity in our thought experiment above is basically the same situation, but at no point did I suggest that the unbound photons in the laser beam were anchored in any particular region of space the way Wheeler did. I didn't need to. The situation is no different, yet it allows an alternate method of deriving both length contraction and time dilation WITHOUT REFERENCE to an origin of a coordinate system. The respective Doppler shifts can be relied upon to yield a similar result without geometry that depends on absolute space or position in an inertialess vacuum. If you understand relativity, you also understand that geometry is of limited utility in a universe defined in all cases by energy transfer events. There is no absolute space other than the geometric centers of the bound energy that is matter. Those centers are not "really" physically fixed with respect to the space they occupy, nor with respect any other particle of matter or boson. There is no absolute time other than the instant of "now" of quantum entanglement, which is intimately related to the properties of the quantum field in which energy that is bound or unbound is merely an excitation.

 

[PhysBang]

I agree it is a real visual effect. When the observer moves around the car, the light angles change from all points of the car relative to the observer, the further away point of the car has a longer length of light and space-time between their eyes and point source. The shorter distance of the angle away has a shorter length of light and space-time between their eyes and observer. When the car is in motion and a relatively stationary observer observers the car passing, the observer , observes a narrower field of light by the relative velocity of the car and angle of the reflected light.

You missed the point. Sadly, the fault lies in part with James R as he wrote a post easy to misinterpret.

You need to read the original text again. http://www.fourmilab.ch/etexts/einstein/specrel/www/

If you believe that the speed of light is a way to synchronize clocks, then you have to believe that an object is shorter relative to any possible ruler moving relative to that object. This is not merely a visual effect, this "rotation" happens for any possible physical interaction, since we can consider any possible interaction to be a form of measurement of the size of the object, i.e., where we will find the object to be.

The "rotation" in question is switching from one system of coordinates to another. Unless you believe that using a new system of coordinates should change physics, you have to believe that the length of an object in one system of coordinates can be different from the length of that object in another system of coordinates.

As far as accelerating a stationary object, because of time dilation, the relativity of simultaneity, and the effect of Maxwell's electrodynamics relative to speed, we can predict contraction.

 

[absolute-space]

You missed the point. Sadly, the fault lies in part with James R as he wrote a post easy to misinterpret.

You need to read the original text again. http://www.fourmilab.ch/etexts/einstein/specrel/www/

If you believe that the speed of light is a way to synchronize clocks, then you have to believe that an object is shorter relative to any possible ruler moving relative to that object. This is not merely a visual effect, this "rotation" happens for any possible physical interaction, since we can consider any possible interaction to be a form of measurement of the size of the object, i.e., where we will find the object to be.

The "rotation" in question is switching from one system of coordinates to another. Unless you believe that using a new system of coordinates should change physics, you have to believe that the length of an object in one system of coordinates can be different from the length of that object in another system of coordinates.

As far as accelerating a stationary object, because of time dilation, the relativity of simultaneity, and the effect of Maxwell's electrodynamics relative to speed, we can predict contraction.

If you believe the speed of light was a way to synchronise clocks, i.e the caesium atom, and these clocks showed a discrepancy in the speed of light frequency of the atom, this would show the speed of light is not constant a variant and time is not affected in any way.

 

[PhysBang]

No it isn't.

I agree that it is not, in general, helpful. It is only helpful to people who are well educated in contemporary mathematics, who recognize that the transformation from one system of coordinates to another is actually a rotation in a certain mathematical context.

However, Minkowski was "sort of" on the right track about one thing. A "rotation" of unbound energy is another mode of propagation of energy, in fact, the ONLY other mode of propagation, other than in a straight line at c. There is a deep relationship between the two modes of propagation of energy, but it isn't even close to the kind of physical rotation Minkowski proposed. Rotation relative to what? Which direction is the rotation?

This, however, is pure fantasy.

Minkowski rotation is not physically either real or meaningful in connection with the relationships between length contractions and time dilations, in four dimensions or otherwise.

Only someone completely ignorant of the relevant mathematics can make this claim. A Minkowski rotation is not a physical rotation through space. However, it is exactly the length contraction and time dilation between one system of coordinates to another. This is just a mathematical fact.

Every physical dimension in this universe in every direction is light travel time

Note that not only is this a fantasy, this is something that danshawen has been asked many times to turn into a proposal that one could actually use to do physics. So far, danshawen has not been able to show how to relate this idea to actually making a measurement. Einstein and Minkowski, on the other hand, show exactly how to relate their ideas to actual measurements. This is why there is so much excellent evidence for contemporary relativity theory.

No it isn't. If you are referring to applications to critical mass cross sections, for example, this geometry doesn't actually work. It doesn't work for any application. Not that anyone involved in such activities would even be able to tell you how badly it fails. It's classified, and they are bound by non-disclosure and other agreements designed to make certain that no one else is let in on the secret.

Ah, so there is some great conspiracy to pretend that relativity theory is one of the most accurately tested theories available. Clifford Will was just filling his books about the tests of relativity theory with stuff he made up, then? All the citations were just fabricated?

The moment a mathematician tries to "plant" the origin of an absolute space into inertialess relativistic space, or even non-static Euclidean dimension of higher order Hilbert spaces, the results of any subsequent calculation based on solid geometry will be as flawed as they are needlessly tortured by an insistence of calculating dynamics based on a static model of geometry.

No mathematician tries to do this. This is more of danshawen's paranoid fantasy. He is confusing his frustrations with mathematics and his anger in general with the behavior of others.

 

[PhysBang]

If you believe the speed of light was a way to synchronise clocks, i.e the caesium atom,

You are confused. These atoms are not used to synchronize clocks, they are used to operate clocks.

Go back and read the text again. Work through the math.

 

[absolute-space]

You are confused. These atoms are not used to synchronize clocks, they are used to operate clocks.

Go back and read the text again. Work through the math.

And you measure of the atom?

 

[Billy T]

I agree it is a real visual effect. ... The shorter distance of the angle away has a shorter length of light and space-time between their eyes and observer. When the car is in motion and a relatively stationary observer observers the car passing, the observer , observes a narrower field of light by the relative velocity of the car and angle of the reflected light. ...

Yes as I discussed in post 11, you can not take a photograph of a moving object (except when shutter opens at time the ends are equally distant from the camera) to measure its actual contracted length; however the contraction is real, not an illusion, and different for observers in different frames, but zero for any observer traveling with the object. It is not only a light transit time effect.

For example, if a train was 100 meters long when stationary at a station in your frame and you do photograph it later when fast moving at a time when the ends are equally distant from your camera it will be less than 100 meters long. You know this as also in the photograph are many sticks you stuck in the ground along side the track, one every cm. You will see that there are less than 10,000 of your sticks with the train directly behind and almost touching them in the photograph. If the train were not contracted, you would see it as behind 10,000 of you 1 cm apart sticks.

 

[absolute-space]

Yes as I discussed in post 11, you can not take a photograph of a moving object (except when shutter opens at time the ends are equally distant from the camera) to measure its actual contracted length; however the contraction is real and different for observers in different frames, but zero for any observer not traveling with the object. It is not only a light transit time effect.

Yes I thought it was, thanks , the confusion comes when people claim other facts which is not facts .

 

[danshawen]

Thank you for your informative post.

You're welcome. I'll try harder not to write it again. It always falls on deaf ears anyway. So anyway, I'm learning ASL right now.

 

[absolute-space]

You're welcome. I'll try harder not to write it again. It always falls on deaf ears anyway. So anyway, I'm learning ASL right now.

ASL?

Do I need hide lol?

Urban dictionary

''asl
What people say on chats to learn who you are and where you live so they can come to your house with a chainsaw and kill you.''