Is a length contraction just a visual thing?

[absolute-space]

Nonetheless, the evidence is that we need to speak of the expansion of space rather than of motion to explain cosmological redshift.

Newtons laws of motion state an object in motion will remain in motion unless there is an acting external force , there is no reasoning that says this principle fails in the reason for the objects motion travelling away from us, space has no fabric and aether was proven to not exist, so what do you propose space is made of if you declare space is expanding?

There is no need to speak of space expanding when it is evidentally not.

 

[absolute-space]

Why do you keep saying that? Who in hell thinks distant objects are flat???

Well, I certainly have tired of beating my head against the wall.

You clearly think distant objects are flat by implying space is expanding, when space has nothing of physical structure to expand, a length of light expansion is not the justification to say space is expanding, there is no evidence of space expanding. Space does not end at the last star we can see.

 

[paddoboy]

There is no need to speak of space expanding when it is evidentally not.

Spacetime is certainly expanding and accelerating in that expansion rate.
The why and how are still somewhat of a mystery, hence we use the term DE.
Science does not know everything, but it certainly knows many times more than any uncredentialed, layperson, who has absolutely no idea about how things work, and who [I suppose luckily] confines himself to a science forum occupying a sliver of cyber space, making not a bit of difference to the accepted tried and true mainstream science and those making the current incredible discoveries.

 

[absolute-space]

Spacetime is certainly expanding and accelerating in that expansion rate.
The why and how are still somewhat of a mystery, hence we use the term DE.
Science does not know everything, but it certainly knows many times more than any uncredentialed, layperson, who has absolutely no idea about how things work, and who [I suppose luckily] confines himself to a science forum occupying a sliver of cyber space, making not a bit of difference to the accepted tried and true mainstream science and those making the current incredible discoveries.

Say's the self proclaimed amateur...

You clearly have no idea about science do you, you can post a link or quote a link, but you have no idea of what you are actually saying or it means do you?

I noticed your intentional distract from the question, I asked you a direct question which again you did not answer in your ignorance and shrugged off with ''science doesn't know everything'' . Contradictory to your apparent claims that science knows ''everything'' and space is expanding which isn't any sort of fact ,no more than set theory.

I ask you again, if you presume the theory of the big bang is accurate and space itself is expanding, then what is space made of? If you can't answer this then you have just proved that when you claim space is expanding is fact, is a lie from yourself.

Do you believe it is good to claim science theory to be fact when it is only a theory?

 

[rpenner]

Of the Lorentz transformation there is a particular thing mentioned of length contraction, is this contraction just from a visual perspective?

This question was directly answered in post #62 where calculations with the Lorentz transform demonstrate that the definition of length, the definition of simultaneity, the definition of co-moving require that length can actually change when you change which inertial motion you use as your standard for deciding what is the meaning of "at rest" and "simultaneous."

Importantly, length contraction has nothing to do with issues of perspective and vision. It's about definitions and standards.

A standard of rest is vital in special relativity if one is to describe the spatial separation of two things at the same time. The (full, 6-parameter) Lorentz transform is the mathematical relation between the description of space-time separations as measured against one standard of rest and choice of spatial coordinates versus the description as measured against another standard. The Lorentz transform I used only had three parameters, as I was interested in representing the new content of special relativity.

In post #99, I expanded on this view, but the OP acts as if I am on ignore.

 

[absolute-space]

This question was directly answered in post #62 where calculations with the Lorentz transform demonstrate that the definition of length, the definition of simultaneity, the definition of co-moving require that length can actually change when you change which inertial motion you use as your standard for deciding what is the meaning of "at rest" and "simultaneous."

Importantly, length contraction has nothing to do with issues of perspective and vision. It's about definitions and standards.

A standard of rest is vital in special relativity if one is to describe the spatial separation of two things at the same time. The (full, 6-parameter) Lorentz transform is the mathematical relation between the description of space-time separations as measured against one standard of rest and choice of spatial coordinates versus the description as measured against another standard. The Lorentz transform I used only had three parameters, as I was interested in representing the new content of special relativity.

In post #99, I expanded on this view, but the OP acts as if I am on ignore.

My apologies, I did not understand your maths so there was not much I could say. I will go back now and try to find a question to ask. Again my apologies.

 

[absolute-space]

In science, a theory is a framework for predicting the behavior of a wide class of phenomena within a certain domain. So the physical theory of special relativity is supported by a great number of empirical observations. The reality of length contraction is a necessary consequence of those empirical observations as it is an elementary consequence of treating two coordinate systems as equally applicable (Principle of Relativity) and endorsing Newton's principle of Inertial and the observation that all observers see the speed of a particular beam of light in vacuum as traveling at the same speed, c.



That's not an illusion. The object is shorter when length and its non-zero motion are not perpendicular. The choice of which coordinates to use is a choice, but that choice has consequences if you want to talk about things like length. It turns out that length is not fundamental in special relativity, because it is a geometry which preserves the space-time interval $$ c^2 (\Delta t)^2 - ( \Delta \vec{x})^2$$ and not length $$ | \Delta \vec{x} | $$.

What do you mean the object is shorter? You mean the object appears to be shorter don't you

 

[rpenner]

What do you mean the object is shorter? You mean the object appears to be shorter don't you

No. Is shorter. Because length has a definition.

Length of an object in inertial motion is the absolute difference in position between the two endpoints at the same time.

Thus the Lorentz transform which describes how position and time transform linearly between inertial coordinate systems, or equally, which describes how differences in position and time transform linearly between inertial coordinate systems, is all that is needed to answer the question.

Standards are important and without clear standards and agreed upon definitions, all debate is pointless. Take a standard sheet of blank paper in standard orientation for writing business correspondence. It is taller than it is wide. Next, turn it 90°. Now it it is wider than it is tall. The paper hasn't changed, but our description of it has changed because (perhaps) we wish to draw a landscape. That's all length of a moving object is, an incomplete description two co-moving points. The full description captures both the length and the state of motion so that one may physically describe it in all states of motion.

 

[absolute-space]

No. Is shorter. Because length has a definition.

Length of an object in inertial motion is the absolute difference in position between the two endpoints at the same time.

Thus the Lorentz transform which describes how position and time transform linearly between inertial coordinate systems, or equally, which describes how differences in position and time transform linearly between inertial coordinate systems, is all that is needed to answer the question.

Huh? I thought we had gone through this one already, the lorenz transformations is of light not of molecular structure. A length of light, you are clearly mistaken.

 

[paddoboy]

Say's the self proclaimed amateur...

Certainly! Why would I claim otherwise? I'm an amateur who has read much reputable material, and have no agenda, religious or otherwise.

You clearly have no idea about science do you, you can post a link or quote a link, but you have no idea of what you are actually saying or it means do you?

And those links, all reputable, totally refute your nonsense, and will keep on coming when needed.
Oh, and yes, in the main I do understand them, far more than yourself obviously and as expressed by the forum in general.

I noticed your intentional distract from the question, I asked you a direct question which again you did not answer in your ignorance and shrugged off with ''science doesn't know everything'' . Contradictory to your apparent claims that science knows ''everything'' and space is expanding which isn't any sort of fact ,no more than set theory.

I've asked you many questions you have ignored. And no I have never claimed science knows everything.Would you like to show me where? Or will you just "shrug" that off as you have with the questions I have asked you?
And spacetime expanding is certainly as near a fact as any scientific theory could be. You do know what a scientific theory is?
And due to that expansion of spacetime, the light we see from the distant Universe is "cosmologically redshifted"
Of course though on a smaller scale the expansion of spacetime is "cancelled out" by gravity and spacetime curvature and matter/energy densities, such as our local group of galaxies and we see that light "Doppler blueshifted" .
More evidence of the larger scale expansion of the Universe/spacetime.

I ask you again, if you presume the theory of the big bang is accurate and space itself is expanding, then what is space made of? If you can't answer this then you have just proved that when you claim space is expanding is fact, is a lie from yourself.

Like I said, science does not know everything but it can explain much. It also logically accepts that which has been supported by observational evidence, such as the curvature and warping of spacetime, the twisting or Lense Thirring effect of spacetime, and more recently the rippling of spacetime, all in the presence of mass. GP-B and LIGO have confirmed spacetime curvature.
Just because we cannot say why it acts this way in the presence of mass, does not detract from the accepted data.

Do you believe it is good to claim science theory to be fact when it is only a theory?

Obviously your confusion is amplified by ignorance.
I have never claimed any scientific theory to be certain, other than the theory of Evolution. Other scientific theories, such as the BB/Inflationary model, SR, GR are though seen as near certain.
The pseudoscience you are pushing, evident by the moving of your threads to more appropriate sections, confirm that status and your own standings on this forum.
Do better.

 

[rpenner]

I have added to my response above. I repeat the new paragraph below for your ease of discourse.

Standards are important and without clear standards and agreed upon definitions, all debate is pointless. Take a standard sheet of blank paper in standard orientation for writing business correspondence. It is taller than it is wide. Next, turn it 90°. Now it it is wider than it is tall. The paper hasn't changed, but our description of it has changed because (perhaps) we wish to draw a landscape. That's all length of a moving object is, an incomplete description two co-moving points. The full description captures both the length and the state of motion so that one may physically describe it in all states of motion.

Huh? I thought we had gone through this one already, the lorenz transformations is of light not of molecular structure. A length of light, you are clearly mistaken.

As someone who used physics to do useful things, I cannot subscribe to your false description of the Lorentz transformation. The Lorentz transform is the six-parameter homogeneous sector of the ten-parameter Poincaré transform of Cartesian coordinate quadruples which describe 4-dimensional space-time in a manner that inertial motion has the description of a straight line. Typically, and in this discussion, we ignore the 3-parameter sector relate to the rotation group in three dimensions of space are are left with only the 3-parameters related to velocity differences between standards of rest. In introductory textbooks, the 1-parameter Lorentz transform where only velocity differences in a single chosen direction is often used for pedagogical reasons. But then one can't easily compare motions parallel to the length and perpendicular to the length without starting the computations from scratch.

Nor is your molecular viewpoint a useful one. We need a physics which describes the behavior of the universe and discussion of molecules is not necessary in description of space and time.

Neither is light required for a description of space and time, but it so happens that light has a very important place in the description of special relativity for light is an example of a massless phenomena which carries energy and momentum.

For a free particle in special relativity:
$$E^2 = c^2 \vec{p}^2 + \left( m c^2 \right)^2 \\ E \vec{v} = c^2 \vec{p} $$
which applies to particles of positive and zero mass. Thus all massless phenomena which convey energy and momentum travel at speed c.

 

[absolute-space]

I have added to my response above.

As someone who used physics to do useful things, I cannot subscribe to your false description of the Lorentz transformation. Nor is your molecular viewpoint a useful one.

The Lorentz transformation are basesd on the velocity of light, you have no idea what you are saying, the maths was impressive but means very little if you think objects physically shrink while in motion. I already sugested an experiment that would show an object in motion did not contract in lenght. It is the light that contracts or expands, nothing to do with the molecular composition of the object decreasing in physical volume.

 

[absolute-space]

Certainly! Why would I claim otherwise? I'm an amateur who has read much reputable material, and have no agenda, religious or otherwise.


And those links, all reputable, totally refute your nonsense, and will keep on coming when needed.
Oh, and yes, in the main I do understand them, far more than yourself obviously and as expressed by the forum in general.

I've asked you many questions you have ignored. And no I have never claimed science knows everything.Would you like to show me where? Or will you just "shrug" that off as you have with the questions I have asked you?
And spacetime expanding is certainly as near a fact as any scientific theory could be. You do know what a scientific theory is?
And due to that expansion of spacetime, the light we see from the distant Universe is "cosmologically redshifted"
Of course though on a smaller scale the expansion of spacetime is "cancelled out" by gravity and spacetime curvature and matter/energy densities, such as our local group of galaxies and we see that light "Doppler blueshifted" .
More evidence of the larger scale expansion of the Universe/spacetime.

Like I said, science does not know everything but it can explain much. It also logically accepts that which has been supported by observational evidence, such as the curvature and warping of spacetime, the twisting or Lense Thirring effect of spacetime, and more recently the rippling of spacetime, all in the presence of mass. GP-B and LIGO have confirmed spacetime curvature.
Just because we cannot say why it acts this way in the presence of mass, does not detract from the accepted data.

Obviously your confusion is amplified by ignorance.
I have never claimed any scientific theory to be certain, other than the theory of Evolution. Other scientific theories, such as the BB/Inflationary model, SR, GR are though seen as near certain.
The pseudoscience you are pushing, evident by the moving of your threads to more appropriate sections, confirm that status and your own standings on this forum.
Do better.

You are claiming science knows everything when you post a theory link and then defend that link saying it is fact. You are saying without saying it, that the theory is complete, everything is known. If science can not prove space itself is made of anything and then say it is expanding, an equal and valid argument would be it is not expanding.

You say there is evidence of space expanding, there isn't, you clearly have this wrong.


''And spacetime expanding is certainly as near a fact as any scientific theory could be.''

It is nowhere near being a fact unless space can be proved to be made of substance.

 

[absolute-space]

Nor is your molecular viewpoint a useful one. We need a physics which describes the behavior of the universe and discussion of molecules is not necessary in description of space and time.

.

Then you are not accounting for time-dilation and the change of space-time.

What do you mean by free particle?

 

[rpenner]

The Lorentz transformation are basesd on the velocity of light, you have no idea what you are saying, the maths was impressive but means very little if you think objects physically shrink while in motion. I already sugested an experiment that would show an object in motion did not contract in lenght. It is the light that contracts or expands, nothing to do with the molecular composition of the object decreasing in physical volume.

The question in the OP was about the physics described by the Lorentz transform. Thus it can be answered without reference to the actual behavior of the universe. Your quaint worries about light and molecular composition and volume are sterile and without basis when you do not address the definition:

Length of an object in inertial motion is the absolute difference in position between the two endpoints at the same time.​

The speed of light does not appear in the Lorentz transform. What appears is the constant $$K = \frac{1}{c^2}$$. Thus experiments can be done with a test-version of the Lorentz transform in situations where the parameter K is not assumed. The experimental picture has uniformly supported the position that $$K = \frac{1}{c^2}$$ better described the behavior of all aspects of the universe better than $$K = 0$$. As with the momentum-energy relationship of particles, c is not in physics formulas because they describe light (Maxwell's equations excepted) but because we inhabit a universe were $$K = \frac{1}{c^2}$$ is a physical constant that affects all space-time relationships, not just light.

Further, the first experiment sensitive enough to distinguish between $$K = \frac{1}{c^2}$$ and $$K = 0$$ dates back to 1859. Twenty years before Einstein was born. Thus by 1905, there was plenty wrong with physics that could only be solved by addressing the elephant in the room: space and time were not absolute in the sense of Newtonian physics.

So if in some post you have a vague idea of a further test of special relativity, you should first explain the implications of your viewpoint in light of all of special relativity's successes. Otherwise, you will be quickly labeled as a person who values his own ego more than correctly describing the behavior of the universe.

 

[absolute-space]

c is not in physics formulas because they describe light

Clearly a wind up, c does not describe light, c is a constant speed of light, E=mc² the most famous physics equation ever which uses the speed of light. Nice try but clearly you are talking gibberish.

 

[rpenner]

Then you are not accounting for time-dilation

Already addressed by the Lorentz transform.

and the change of space-time.

Space-time doesn't change under the Lorentz transform. Only the incomplete descriptions of space-time, like position and time of event change. That's because position and time of event are coordinates which describe only aspects of space-time.

The analogy with the sheet of paper being turned 90° remains appropriate.

What do you mean by free particle?

In this case, any bounded phenomena which propagates inertially and carries energy and momentum. A rock, an electron, a photon, a molecule of water -- all can be spatially localized and tossed from place-to-place in conditions where outside forces are negligible.

 

[rpenner]

Clearly a wind up, c does not describe light, c is a constant speed of light, E=mc² the most famous physics equation ever which uses the speed of light. Nice try but clearly you are talking gibberish.

No. I'm saying c does not uniquely describe light. It's in $$E=mc^2$$ which explains why a given number of uranium-235 atoms masses more than the same number of protons and neutrons arranged into atoms with about half the atomic number. It's in those equations that relate energy and momentum for a free particle, including neutrinos which don't even interact with light at all.

$$c = \sqrt{\frac{1}{K}} $$ is a physically important constant which Maxwell identified as the speed of light, but which special relativity shows has a much deeper significance.

The historical accident of Maxwell describing electromagentism before Einstein described space, time, energy and momementum better than anyone before him doesn't forever alter the fact that in our universe $$K$$ has more significant than just relating to light. In fact, many physics textbooks choose to use units where $$K=1$$ even when not dealing with light, so ubiquitous is the this fact about the behavior of our universe.

 

[absolute-space]

No. I'm saying c does not uniquely describe light. It's in $$E=mc^2$$ which explains why a given number of uranium-235 atoms masses more than the same number of protons and neutrons arranged into atoms with about half the atomic number. It's in those equations that relate energy and momentum for a free particle, including neutrinos which don't even interact with light at all.

$$c = \sqrt{\frac{1}{K}} $$ is a physically important constant which Maxwell identified as the speed of light, but which special relativity shows has a much deeper significance.

The historical accident of Maxwell describing electromagentism before Einstein described space, time, energy and momementum better than anyone before him doesn't forever alter the fact that in our universe $$K$$ has more significant than just relating to light. In fact, many physics textbooks choose to use units where $$K=1$$ even when not dealing with light, so ubiquitous is the this fact about the behavior of our universe.

Thank you for the information, you are evidentially an authority on science and know your knowledge. Let me take this slowly, is K a constant of 0 but some textbooks use 1?

 

[paddoboy]

You are claiming science knows everything when you post a theory link and then defend that link saying it is fact. You are saying without saying it, that the theory is complete, everything is known. If science can not prove space itself is made of anything and then say it is expanding, an equal and valid argument would be it is not expanding.

Don't be such a silly Billy.....The scientific evidence supports expansion, in fact it supports accelerated expansion.
What you claim is invalidated by the evidence.
You have nothing other than a unsupported hypothesis.
And again, no matter how many times you chose to lie, I have never said science knows everything. But that beats knowing nothing!

You say there is evidence of space expanding, there isn't, you clearly have this wrong.

No, I clearly have it right......
And perhaps you need to calm down some...perhaps a Disprin and a good lay down?
http://cosmictimes.gsfc.nasa.gov/online_edition/1929Cosmic/expanding.html
Edwin Hubble showed that there is a connection between the distance to a remote galaxy and the redshift in the spectral lines of that galaxy.
This is a redshift, more correctly known as a cosmological redshift.

''And spacetime expanding is certainly as near a fact as any scientific theory could be.''
It is nowhere near being a fact unless space can be proved to be made of substance.

No, that's rubbish and actually a cop out often used by cranks and trolls.
http://www.pbs.org/wgbh/aso/databank/entries/dp29hu.html

And of course the other tit bit of proof the Universe is expanding over large scales is the expansion being overwhelmed over smaller scales of increased matter/energy densities and hence spacetime curvature and gravity such as our own local group of galaxies. Something you insidiously side stepped.


Now a couple of questions which I have no doubt you will side step or ignore....
[1]What are your credentials to write of 21st century accepted cosmology, in favour of your own mythical fabricated story?
[2]Have you ever been banned on any other forum?