A constant speed of light in all reference frames? Surely you can't be serious. [Physics]

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From: PD on 16 Feb 2010 13:46

On Feb 16, 12:25 pm, kenseto <kens...(a)erinet.com> wrote:
> On Feb 16, 11:00 am, PD <thedraperfam...(a)gmail.com> wrote:
>
>
>
> > On Feb 16, 8:13 am, kenseto <kens...(a)erinet.com> wrote:
>
> > > On Feb 15, 10:32 pm, "Inertial" <relativ...(a)rest.com> wrote:
>
> > > > "kenseto" <kens...(a)erinet.com> wrote in message
>
> > > >news:65fb4cc2-4dcb-4a03-a564-a5787f7e3550(a)w31g2000yqk.googlegroups.com...
>
> > > > > On Feb 15, 5:16 pm, "Inertial" <relativ...(a)rest.com> wrote:
> > > > >> "kenseto" <kens...(a)erinet.com> wrote in message
>
> > > > >>news:65b0b432-ea12-4f62-8dea-14b916d28a20(a)15g2000yqi.googlegroups..com...
>
> > > > >> > On Feb 15, 4:06 pm, PD <thedraperfam...(a)gmail.com> wrote:
> > > > >> >> On Feb 15, 2:38 pm, kenseto <kens...(a)erinet.com> wrote:
>
> > > > >> >> > On Feb 15, 12:27 pm, mpalenik <markpale...(a)gmail.com> wrote:
>
> > > > >> >> > > On Feb 15, 6:54 am, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > >> >> > > > On 14 Feb, 23:46, mpalenik <markpale...(a)gmail.com> wrote:
>
> > > > >> >> > > > > On Feb 14, 2:03 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > >> >> > > > > > I'm afraid you're easily satisifed Tom. As I say, I'm not
> > > > >> >> > > > > > really
> > > > >> >> > > > > > interested in learning geometry, or talking about completely
> > > > >> >> > > > > > hypothetical "grooves in spacetime".
>
> > > > >> >> > > > > And as many people have repeatedly tried to explain to you,
> > > > >> >> > > > > the
> > > > >> >> > > > > answer
> > > > >> >> > > > > simply is geometry. When you accellerate, you rotate in
> > > > >> >> > > > > spacetime.
> > > > >> >> > > > > Why? Because that's what accelleration means. That's what it
> > > > >> >> > > > > means
> > > > >> >> > > > > to be travelling with a certain velocity with respect to
> > > > >> >> > > > > something
> > > > >> >> > > > > else. It means that you're both "facing different
> > > > >> >> > > > > directions".
> > > > >> >> > > > > Every
> > > > >> >> > > > > effect predicted by relativity can be explained simply by the
> > > > >> >> > > > > fact
> > > > >> >> > > > > that two different observers at different speeds are "facing
> > > > >> >> > > > > different
> > > > >> >> > > > > directions" in spacetime--because that's what it means to be
> > > > >> >> > > > > moving
> > > > >> >> > > > > with respect to something else. It means that you have a
> > > > >> >> > > > > different t
> > > > >> >> > > > > and x axis.
>
> > > > >> >> > > > Mark, if you consider this an answer, then you simply haven't
> > > > >> >> > > > understood the question.- Hide quoted text -
>
> > > > >> >> > > > - Show quoted text -
>
> > > > >> >> > > And if you think there's more to it than that, then you haven't
> > > > >> >> > > understood the answer. The above explains everything about
> > > > >> >> > > relativity
> > > > >> >> > > and there's no ambiguity when you understand it.
>
> > > > >> >> > > Going back to the fitting a ladder into a barn analogy, it's like
> > > > >> >> > > you
> > > > >> >> > > have a ladder to long to fit into the barn, you turn it at an
> > > > >> >> > > angle,
> > > > >> >> > > and it fits, and then someone starts asking you what "physically"
> > > > >> >> > > happened to the ladder. You say "well, it got rotated, so it's
> > > > >> >> > > shorter in the horizontal direction". Then the person keeps
> > > > >> >> > > demanding
> > > > >> >> > > a physical explanation, and you say you just rotated the ladder,
> > > > >> >> > > so
> > > > >> >> > > it
> > > > >> >> > > takes up a bit more space in the vertical and less in the
> > > > >> >> > > horizontal
> > > > >> >> > > but the total length of the ladder didn't change.
>
> > > > >> >> > In this case you are not fitting the length of the ladder through a
> > > > >> >> > narrow door way. You are fitting a skinny side of the ladder through
> > > > >> >> > a
> > > > >> >> > wider door way.
> > > > >> >> > This is not the same as an 80 ft long material pole can fit into a
> > > > >> >> > 40
> > > > >> >> > ft long material barn with both doors close simultaneously. In this
> > > > >> >> > case material contraction must occur. That's thee reason why modern
> > > > >> >> > interpretation of length contraction in Sr is merely a geometric
> > > > >> >> > effect instead of material or physical effect as asserted by the
> > > > >> >> > runts of the SRians such as PD and you.
>
> > > > >> >> "Material" does not mean the same thing as "physical", Ken.
> > > > >> >> This has been pointed out even in the common dictionary.
> > > > >> >> If you can't let go of your mistakes, Ken, you'll never get off square
> > > > >> >> one.
>
> > > > >> > Physical is material....is one of the definitions in my dictionary.
>
> > > > >> My dictionary says it is relating to the human body (as opposed to mind
> > > > >> or
> > > > >> spirit), or involving bodily contact. So if you mean length contraction
> > > > >> in
> > > > >> SR is not physical because it does not involve human body contact, then
> > > > >> I'd
> > > > >> agree.
>
> > > > >> In any case, SR says the all the atoms of a moving rod are closer
> > > > >> together
> > > > >> (in the frame of a relatively moving observer). ie. that the spatial
> > > > >> distance between them (at any given time) is shorter than when the rod is
> > > > >> at
> > > > >> rest. That sounds 'physically' shorter to me.
>
> > > > > Hey idiot
>
> > > > I'm no idiot, as you know. But I'll respond to you anyway.
>
> > > > > do you realize that you were describing material length
> > > > > contraction and not merely geometric projection contraction?
>
> > > > The geometric projection results in the atoms being closer together in the
> > > > frame in which the rod is moving.
>
> > > No...this is wrong. I see you to be shorter from a distance is
> > > geometric projection. The atoms in you are not being closer together.
>
> > > > As I said above. The effect of the
> > > > geometric projection (rotation) is that the atoms physically get closer.
> > > > Geometric operations can have physical results. Like rotating a ladder to
> > > > fit through a doorway.
>
> > > Geometric projection has no material or physical effect. When you
> > > rotate the x-axis around the time axis the projected x value onto the
> > > original non-roatated x-axis is shorter. That is not a physical or
> > > material effect.
> > > When you said that the atoms get closer together that's is a physical
> > > or material effect.
>
> > > > > If
> > > > > material length contraction occur how come from the pole frame point
> > > > > of view there is no material length contraction
>
> > > > There is a unity projection from pole frame to pole frame .. so no change as
> > > > a result
>
> > > So from the pole point of view the pole is not able to fit into the
> > > barn physically or materially. And at the same time the barn frame
> > > observer insisted that the material pole is able to fit into the barn
> > > materially or physically. That sound like a contradiction to me.
>
> > > > > and thus it is not
> > > > > able to fit into the barn?
>
> > > > It fits in the barn in the barn frame at some time in the barn frame.
>
> > > I am afraid that you don't understand SR. SR only claim that the
> > > projected length (not the material length or physical length) is able
> > > to fit into the barn frame.
>
> > > >There
> > > > is no time in the pole frame where that is true. That is due to the
> > > > differences in time in those two frames
>
> > > Right the material length is not able to fit into the material barn.
> > > Your problem is that you want length contraction to be material or
> > > physical instead of accepting the new SR interpretation that length
> > > contract is not material or physical.
>
> > > > > Do you realize that material length
> > > > > contraction is frame independent?
>
> > > > Depends on what you mean by 'length'. What is your definition of the length
> > > > of a rod?
>
> > > Length of a meter stick is its physical or material length.
>
> > Material does not mean physical. Don't choose definitions to suit you.
> > Use the one that is appropriate.
>
> Sure material means physical. Geometric projection does not mean
> physical.

Picking and choosing your definitions, Ken?
Look at the definitions I highlighted for you.
Look at your freshman physics textbook. Does it tell you that the
electric field is not physical?

>
>
>
> > > There is no physical or material length contraction in my theory. The
> > > observer assumes that the light path length of his meter stick is its
> > > physical length (1 meter long). He uses this assumed standard and the
> > > IRT equations to predict the light path length for a meter stick
> > > moving wrt him to be: 1/gamma or (gamma) meters long. The reason for
> > > the two prediction is that the observer does not know if the moving
> > > stick has a higher or lower light path length.
> > > My theory is described in the following link:http://www.modelmechanics.org/2008irt.dtg.pdf
>
> > > Ken Seto- Hide quoted text -
>
> > - Show quoted text -- Hide quoted text -
>
> > - Show quoted text -

From: kenseto on 16 Feb 2010 13:57

On Feb 16, 1:46 pm, PD <thedraperfam...(a)gmail.com> wrote:
> On Feb 16, 12:25 pm, kenseto <kens...(a)erinet.com> wrote:
>
>
>
>
>
> > On Feb 16, 11:00 am, PD <thedraperfam...(a)gmail.com> wrote:
>
> > > On Feb 16, 8:13 am, kenseto <kens...(a)erinet.com> wrote:
>
> > > > On Feb 15, 10:32 pm, "Inertial" <relativ...(a)rest.com> wrote:
>
> > > > > "kenseto" <kens...(a)erinet.com> wrote in message
>
> > > > >news:65fb4cc2-4dcb-4a03-a564-a5787f7e3550(a)w31g2000yqk.googlegroups..com...
>
> > > > > > On Feb 15, 5:16 pm, "Inertial" <relativ...(a)rest.com> wrote:
> > > > > >> "kenseto" <kens...(a)erinet.com> wrote in message
>
> > > > > >>news:65b0b432-ea12-4f62-8dea-14b916d28a20(a)15g2000yqi.googlegroups.com...
>
> > > > > >> > On Feb 15, 4:06 pm, PD <thedraperfam...(a)gmail.com> wrote:
> > > > > >> >> On Feb 15, 2:38 pm, kenseto <kens...(a)erinet.com> wrote:
>
> > > > > >> >> > On Feb 15, 12:27 pm, mpalenik <markpale...(a)gmail.com> wrote:
>
> > > > > >> >> > > On Feb 15, 6:54 am, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > > >> >> > > > On 14 Feb, 23:46, mpalenik <markpale...(a)gmail.com> wrote:
>
> > > > > >> >> > > > > On Feb 14, 2:03 pm, Ste <ste_ro...(a)hotmail.com> wrote:
>
> > > > > >> >> > > > > > I'm afraid you're easily satisifed Tom. As I say, I'm not
> > > > > >> >> > > > > > really
> > > > > >> >> > > > > > interested in learning geometry, or talking about completely
> > > > > >> >> > > > > > hypothetical "grooves in spacetime".
>
> > > > > >> >> > > > > And as many people have repeatedly tried to explain to you,
> > > > > >> >> > > > > the
> > > > > >> >> > > > > answer
> > > > > >> >> > > > > simply is geometry. When you accellerate, you rotate in
> > > > > >> >> > > > > spacetime.
> > > > > >> >> > > > > Why? Because that's what accelleration means. That's what it
> > > > > >> >> > > > > means
> > > > > >> >> > > > > to be travelling with a certain velocity with respect to
> > > > > >> >> > > > > something
> > > > > >> >> > > > > else. It means that you're both "facing different
> > > > > >> >> > > > > directions".
> > > > > >> >> > > > > Every
> > > > > >> >> > > > > effect predicted by relativity can be explained simply by the
> > > > > >> >> > > > > fact
> > > > > >> >> > > > > that two different observers at different speeds are "facing
> > > > > >> >> > > > > different
> > > > > >> >> > > > > directions" in spacetime--because that's what it means to be
> > > > > >> >> > > > > moving
> > > > > >> >> > > > > with respect to something else. It means that you have a
> > > > > >> >> > > > > different t
> > > > > >> >> > > > > and x axis.
>
> > > > > >> >> > > > Mark, if you consider this an answer, then you simply haven't
> > > > > >> >> > > > understood the question.- Hide quoted text -
>
> > > > > >> >> > > > - Show quoted text -
>
> > > > > >> >> > > And if you think there's more to it than that, then you haven't
> > > > > >> >> > > understood the answer. The above explains everything about
> > > > > >> >> > > relativity
> > > > > >> >> > > and there's no ambiguity when you understand it.
>
> > > > > >> >> > > Going back to the fitting a ladder into a barn analogy, it's like
> > > > > >> >> > > you
> > > > > >> >> > > have a ladder to long to fit into the barn, you turn it at an
> > > > > >> >> > > angle,
> > > > > >> >> > > and it fits, and then someone starts asking you what "physically"
> > > > > >> >> > > happened to the ladder. You say "well, it got rotated, so it's
> > > > > >> >> > > shorter in the horizontal direction". Then the person keeps
> > > > > >> >> > > demanding
> > > > > >> >> > > a physical explanation, and you say you just rotated the ladder,
> > > > > >> >> > > so
> > > > > >> >> > > it
> > > > > >> >> > > takes up a bit more space in the vertical and less in the
> > > > > >> >> > > horizontal
> > > > > >> >> > > but the total length of the ladder didn't change.
>
> > > > > >> >> > In this case you are not fitting the length of the ladder through a
> > > > > >> >> > narrow door way. You are fitting a skinny side of the ladder through
> > > > > >> >> > a
> > > > > >> >> > wider door way.
> > > > > >> >> > This is not the same as an 80 ft long material pole can fit into a
> > > > > >> >> > 40
> > > > > >> >> > ft long material barn with both doors close simultaneously. In this
> > > > > >> >> > case material contraction must occur. That's thee reason why modern
> > > > > >> >> > interpretation of length contraction in Sr is merely a geometric
> > > > > >> >> > effect instead of material or physical effect as asserted by the
> > > > > >> >> > runts of the SRians such as PD and you.
>
> > > > > >> >> "Material" does not mean the same thing as "physical", Ken.
> > > > > >> >> This has been pointed out even in the common dictionary.
> > > > > >> >> If you can't let go of your mistakes, Ken, you'll never get off square
> > > > > >> >> one.
>
> > > > > >> > Physical is material....is one of the definitions in my dictionary.
>
> > > > > >> My dictionary says it is relating to the human body (as opposed to mind
> > > > > >> or
> > > > > >> spirit), or involving bodily contact. So if you mean length contraction
> > > > > >> in
> > > > > >> SR is not physical because it does not involve human body contact, then
> > > > > >> I'd
> > > > > >> agree.
>
> > > > > >> In any case, SR says the all the atoms of a moving rod are closer
> > > > > >> together
> > > > > >> (in the frame of a relatively moving observer). ie. that the spatial
> > > > > >> distance between them (at any given time) is shorter than when the rod is
> > > > > >> at
> > > > > >> rest. That sounds 'physically' shorter to me.
>
> > > > > > Hey idiot
>
> > > > > I'm no idiot, as you know. But I'll respond to you anyway.
>
> > > > > > do you realize that you were describing material length
> > > > > > contraction and not merely geometric projection contraction?
>
> > > > > The geometric projection results in the atoms being closer together in the
> > > > > frame in which the rod is moving.
>
> > > > No...this is wrong. I see you to be shorter from a distance is
> > > > geometric projection. The atoms in you are not being closer together.
>
> > > > > As I said above. The effect of the
> > > > > geometric projection (rotation) is that the atoms physically get closer.
> > > > > Geometric operations can have physical results. Like rotating a ladder to
> > > > > fit through a doorway.
>
> > > > Geometric projection has no material or physical effect. When you
> > > > rotate the x-axis around the time axis the projected x value onto the
> > > > original non-roatated x-axis is shorter. That is not a physical or
> > > > material effect.
> > > > When you said that the atoms get closer together that's is a physical
> > > > or material effect.
>
> > > > > > If
> > > > > > material length contraction occur how come from the pole frame point
> > > > > > of view there is no material length contraction
>
> > > > > There is a unity projection from pole frame to pole frame .. so no change as
> > > > > a result
>
> > > > So from the pole point of view the pole is not able to fit into the
> > > > barn physically or materially. And at the same time the barn frame
> > > > observer insisted that the material pole is able to fit into the barn
> > > > materially or physically. That sound like a contradiction to me.
>
> > > > > > and thus it is not
> > > > > > able to fit into the barn?
>
> > > > > It fits in the barn in the barn frame at some time in the barn frame.
>
> > > > I am afraid that you don't understand SR. SR only claim that the
> > > > projected length (not the material length or physical length) is able
> > > > to fit into the barn frame.
>
> > > > >There
> > > > > is no time in the pole frame where that is true. That is due to the
> > > > > differences in time in those two frames
>
> > > > Right the material length is not able to fit into the material barn..
> > > > Your problem is that you want length contraction to be material or
> > > > physical instead of accepting the new SR interpretation that length
> > > > contract is not material or physical.
>
> > > > > > Do you realize that material length
> > > > > > contraction is frame independent?
>
> > > > > Depends on what you mean by 'length'. What is your definition of the length
> > > > > of a rod?
>
> > > > Length of a meter stick is its physical or material length.
>
> > > Material does not mean physical. Don't choose definitions to suit you..
> > > Use the one that is appropriate.
>
> > Sure material means physical. Geometric projection does not mean
> > physical.
>
> Picking and choosing your definitions, Ken?
> Look at the definitions I highlighted for you.
> Look at your freshman physics textbook. Does it tell you that the
> electric field is not physical?

In the past you insisted that length contraction in SR is physical and
at that time you think that physical means material. You even
suggested that length contraction can be measured directly by shooting
lasers from the ends of a moving ruler to the rest frame of the
observer. So you see you think that length contraction in SR is
material.
Also your SR brother Inertial said in this thread that contraction in
SR means that the atoms get closer....this means material contraction.
>
>
>
>
>
> > > > There is no physical or material length contraction in my theory. The
> > > > observer assumes that the light path length of his meter stick is its
> > > > physical length (1 meter long). He uses this assumed standard and the
> > > > IRT equations to predict the light path length for a meter stick
> > > > moving wrt him to be: 1/gamma or (gamma) meters long. The reason for
> > > > the two prediction is that the observer does not know if the moving
> > > > stick has a higher or lower light path length.
> > > > My theory is described in the following link:http://www.modelmechanics.org/2008irt.dtg.pdf
>
> > > > Ken Seto- Hide quoted text -
>
> > > - Show quoted text -- Hide quoted text -
>
> > > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -

From: PD on 16 Feb 2010 14:04

On Feb 16, 12:57 pm, kenseto <kens...(a)erinet.com> wrote:
> On Feb 16, 1:46 pm, PD <thedraperfam...(a)gmail.com> wrote:

>
> > Picking and choosing your definitions, Ken?
> > Look at the definitions I highlighted for you.
> > Look at your freshman physics textbook. Does it tell you that the
> > electric field is not physical?
>
> In the past you insisted that length contraction in SR is physical and
> at that time you think that physical means material.

No, sir, I *never* said length contraction was material. I said it was
PHYSICAL.

> You even
> suggested that length contraction can be measured directly by shooting
> lasers from the ends of a moving ruler to the rest frame of the
> observer.

Yes, it is MEASURABLE. Physical things are measurable.
Energy is MEASURABLE, it is not material.
Magnetic fields are MEASURABLE, they are not material.
Radio waves are MEASURABLE, they are not material.

> So you see you think that length contraction in SR is
> material.

No, it is MEASURABLE. It is not material.

> Also your SR brother Inertial said in this thread that contraction in
> SR means that the atoms get closer....this means material contraction.

Ken, rather than desperately trying to gather excuses to support your
mistaken impression, why don't you just take another look at the
correct definitions for physical that I've already shown you? Why
don't you reread your freshman physics text again, and check whether
it says the electric field is not physical? If you've made a small
mistake, then CORRECT IT and move on. If you cannot ever correct a
small mistake, you'll never get out of square one. You'll spend all
your time searching newsgroups for support for your mistake.

PD

From: PD on 16 Feb 2010 15:27

On Feb 16, 2:15 pm, kenseto <kens...(a)erinet.com> wrote:
> On Feb 16, 2:10 pm, PD <thedraperfam...(a)gmail.com> wrote:
>
> > On Feb 16, 1:01 pm, kenseto <kens...(a)erinet.com> wrote:
>
> > > If length contraction in SR is not material or physical how does an 80
> > > ft long material pole fit inside a 40 ft long material barn?
>
> > Length contraction is physical. It is not material. The two do not
> > mean the same thing.
> > There are lots of physical effects in nature that not material.
>
> > The pole is 80 feet long only in its rest frame. That is where you
> > take a ruler and lay it along the pole while it is at REST. This is
> > the ONLY circumstance in which that pole is 80 feet long -- when it is
> > at rest. This is included in the instruction manual for measuring the
> > length of things with the ruler. When you measure the pole under any
> > other conditions other than it being at rest, it is no longer an 80
> > foot pole. It is a shorter pole. This is a physical, measurable effect
> > that is NOT material compression.
>
> Hey idiot no measurement of a moving ruler ever been
> made....

Nevertheless, length contraction has been indirectly measured.
It is not necessary that the measurement be done with a ruler.

> prediction is not a measurement.

It's been *measured*, not just predicted. Theories don't have any
value unless a significant number of its predictions have been checked
against experiment. This has been done for relativity. You seem to
think that relativity predicts a bunch of stuff but that none of it
has been measured. That's just plain wrong.

> Geometric projection
> prediction is not physical.

Geometry is a core aspect of the physical. This, if you'll re-read
what Tom Roberts has been saying, is *EXACTLY* what what he's been
telling you.

> It is a optical effect.

No, it's not. It has nothing to do with optics. Length contraction has
been indirectly measured where no light is used to gather the data.

> You runts of the
> SRians want it both way...you want length contraction to be physical
> (whatever that means)

Yes. Now, it may benefit you to learn what "physical" means. I've
given you a number of references, including your own freshman
textbook, to check that out. It does NOT mean material.

> and you want it to be merely a geometrical
> projection effect.

Yes. Geometry is a core aspect of physics. I don't know where you ever
got the impression that it was not.
For example, you'll notice in your freshman physics textbook something
called Gauss' Law. This is an important result of the *geometry* of
space in physics.

> For example your SR brother said that length
> contraction is the atoms in a ruler get closer together....that is
> material contraction.

He said it was PHYSICAL. YOU said it was material. You don't know the
difference.

> OTOH,Your SR brother Tom Roberts said that
> length contraction in SR is not physical...iow, the physical length of
> the ruler is not contracted.

He didn't say it wasn't physical. He said you had a poor understanding
of what "physical" means, and so he wasn't going to try to use your
meaning of that term.

But here again is where we get back to the fundamental issue, Ken, and
that is you are trying to learn relativity from a newsgroup. You don't
know the right answers and so you have to complain when one person on
the newsgroup leads you to one impression, and another person on the
newsgroup leads you to a different impression, and you don't know
which to believe. This should tell you that it is STUPID to try to
learn relativity from a newsgroup.

>
> > When you get it through your thick head that physical does not mean
> > material, then you'll stop looking for material effects.
>

From: Inertial on 16 Feb 2010 18:17

"PD" <thedraperfamily(a)gmail.com> wrote in message
news:995b34f4-be02-48bb-b9db-463e3437283a(a)j27g2000yqn.googlegroups.com...
> On Feb 16, 12:57 pm, kenseto <kens...(a)erinet.com> wrote:
>> On Feb 16, 1:46 pm, PD <thedraperfam...(a)gmail.com> wrote:
>
>>
>> > Picking and choosing your definitions, Ken?
>> > Look at the definitions I highlighted for you.
>> > Look at your freshman physics textbook. Does it tell you that the
>> > electric field is not physical?
>>
>> In the past you insisted that length contraction in SR is physical and
>> at that time you think that physical means material.
>
> No, sir, I *never* said length contraction was material. I said it was
> PHYSICAL.
>
>> You even
>> suggested that length contraction can be measured directly by shooting
>> lasers from the ends of a moving ruler to the rest frame of the
>> observer.
>
> Yes, it is MEASURABLE. Physical things are measurable.
> Energy is MEASURABLE, it is not material.
> Magnetic fields are MEASURABLE, they are not material.
> Radio waves are MEASURABLE, they are not material.
>
>> So you see you think that length contraction in SR is
>> material.
>
> No, it is MEASURABLE. It is not material.
>
>> Also your SR brother Inertial said in this thread that contraction in
>> SR means that the atoms get closer....this means material contraction.
>
> Ken, rather than desperately trying to gather excuses to support your
> mistaken impression, why don't you just take another look at the
> correct definitions for physical that I've already shown you? Why
> don't you reread your freshman physics text again, and check whether
> it says the electric field is not physical? If you've made a small
> mistake, then CORRECT IT and move on. If you cannot ever correct a
> small mistake, you'll never get out of square one. You'll spend all
> your time searching newsgroups for support for your mistake.

Note that the atoms in a length-contracted rod are physically closer
together, as measured in the relatively moving inertial frame. In that
frame the material that makes up the rod is fitting within a shorter
distance (ie compressed).

However, the intrinsic/proper/rest length of the rod is unchanged, and the
intrinsic/proper/rest distance between the atoms of its material are
unchanged.

So whether of not it's 'materially' compressed (meaning the atoms of the
material of which it is made are closer together) depends on whether you are
talking about the frame dependent view of the material or the invariant
view. Which, when you say it, is bleedingly obvious.

Also note that just because the contraction is MODELLED by a geometrical
rotation does not mean it there is nothing 'physical' going on wrt
frame-dependent measurement (which is the sort of measurement we work with
every day, and that makes sense).

It all comes down to whether you are referring to frame dependent or
invariant measures. In the pole and barn scenario, when one says "in the
frame of the barn", that implies we are talking about frame-dependant values
... and 'length contraction' means the frame-dependent length of the pole is
shorter, and in a frame-dependent view of the pole, the atoms that make up
its material are closer together.