Time relativity transformation of coordinates

[PengKuan Em]

Without length contraction, time relativity transformation solves paradoxes and explains incongruent relativistic experiments, which allows us to build a transformation of coordinates without length contraction. For abscissa transformation, Figure 1 shows a spaceship in the frame of O1, its backend is at O1 and frontend at A1. At time zero the spaceship is stationary, from time zero to time t1, it is accelerated. The trajectories of its backend and frontend are the parallel curves from O1 to O2 and from A1 to A2. At time t1 the spaceship moves at the velocity v, its backend is at O2 and frontend at A2. So, the frame of O2 moves with the spaceship at the velocity v in the frame of O1.

Because the trajectories of the backend and frontend are parallel, the distance O2A2 constantly equals the distance O1A1 which is the proper length of the spaceship. O2A2 is the length of the moving spaceship in the stationary frame O1. So, the length of the moving spaceship constantly equals its proper length.
…

For Time transformation, The transformation of time from the stationary frame to the mobile frame is like that in special relativity. In Figure 3, at time zero a light signal is sent in the mobile frame from O2 to the mirror M which reflects it back to O2. The time the light signal takes to complete the journey is tO2=2L2/c, with c being the speed of light and L2 the distance from O2 to M. tO2 is also the time of O2. In the stationary frame the light signal is sent when O2 coincides with O1 and goes from O1 to the moving M which reflects it to O2. The time of this journey is tO1=2L1/c, with L1 being the distance from O1 to M. tO1 is also the time of O1. Because L2= L1√(1-v^2/c^2 ), tO1 is related to tO2 by equation (7).

Read the article below.
https://www.academia.edu/42129223/Time_relativity_transformation_of_coordinates
https://pengkuanonphysics.blogspot.com/2020/03/time-relativity-transformation-of.html

[Tom Roberts]

On 3/3/20 3:38 PM, PengKuan Em wrote:
> Without length contraction, time relativity transformation solves

> paradoxes and explains incongruent relativistic experiments,[...]

You are either misinformed, or just making stuff up.

In relativity, the "paradoxes" use the word in this sense:
A seeming contradiction that upon analysis proves to
be correct (and thus consistent).

There are no inconsistencies or contradictions in SR, and within its
domain there are no experiments with results inconsistent with the
predictions of SR (presumably what you mean by "incongruent", which is
the wrong word here).

Note also that transformations between inertial frames are HIGHLY
constrained by the meaning of "inertial frame". What you suggest does
not preserve the structure of inertial frames, and is thus completely
useless.

Apparently you are unaware that the set of all transforms between
inertial frames must form a group. What you suggest does not.

Given the properties of inertial frames, there are
only three possible transformation groups that can
relate the coordinates of one frame to those of
another: Euclid, Galilei, and Lorentz. Of them, only
the Lorentz group agrees with experiments (locally).

Tom Roberts

[Ned Latham]

Tom Roberts wrote:

----snip----

> Given the properties of inertial frames, there are
> only three possible transformation groups that can
> relate the coordinates of one frame to those of
> another: Euclid, Galilei, and Lorentz. Of them, only
> the Lorentz group agrees with experiments (locally).

False. Galileian transforms agrree with experiments within
the limits of experiemtal error, and Euclidean transforms
agree with experiments within the limits of the application
of Euclidean tranforms.

[Burl Walker]

Tom Roberts wrote:

> On 3/3/20 3:38 PM, PengKuan Em wrote:
>> Without length contraction, time relativity transformation solves
>> paradoxes and explains incongruent relativistic experiments,[...]
>
> You are either misinformed, or just making stuff up.
>
> In relativity, the "paradoxes" use the word in this sense:
> A seeming contradiction that upon analysis proves to be correct (and
> thus consistent).

there is not such sense. You make shit as you go. A paradox is a paradox.
As dog is a dog and a cat is a cat. A cat cannot be not a cat.

[Tom Roberts]

On 3/4/20 12:12 PM, Ned Latham wrote:

> Tom Roberts wrote:
>> Given the properties of inertial frames, there are
>> only three possible transformation groups that can
>> relate the coordinates of one frame to those of
>> another: Euclid, Galilei, and Lorentz. Of them, only
>> the Lorentz group agrees with experiments (locally).
>
> False. Galileian transforms agrree with experiments within
> the limits of experiemtal error,

This is just plain not true. The tens of thousands of particle
accelerators around the world refute Galilean relativity every day. Not
to mention the hundreds of experiments that have explicitly tested
various predictions of SR that are inconsistent with Galilean
relativity. For some experiments and measurements, the results differ
from the Galilean prediction by thousands of sigma.

I use "sigma" in the physicist's sense, meaning the
standard deviation of a given measurement's value.
Experimental physicists expend major efforts to
measure it. Five sigma is the usual standard for a
discovery; a discrepancy of tens or hundreds or
thousands of sigma mean the theory's prediction is
just completely and utterly wrong.

Here's a simple example: At CERN the LHC accelerates protons to a
kinetic energy of 6 TeV, measured with an accuracy about 200 parts per
million. Their speed is measured to be 299792000 m/s, measured with an
accuracy better than 1 part per million. The proton mass is known to
much better than a part per million. So Galilean relativity predicts
each proton has a a kinetic energy (0.5*m*v^2) of 7.5E-11 Joule. The
actual measurement of 6 TeV corresponds to 9.6E-7 Joule, more than 5,000
sigma from the Galilean prediction. Galilean relativity is completely
and utterly WRONG.

Just because you are unaware of experiments does not mean they don't
exist. Just because you wish away everything that disagrees with your
personal hopes and dreams does not mean that your fantasy world
corresponds to the one we inhabit.

Tom Roberts

[PengKuan Em]

Le mercredi 4 mars 2020 22:03:02 UTC+1, tjrob137 a écrit :
> Here's a simple example: At CERN the LHC accelerates protons to a
> kinetic energy of 6 TeV, measured with an accuracy about 200 parts per
> million. Their speed is measured to be 299792000 m/s, measured with an
> accuracy better than 1 part per million. The proton mass is known to
> much better than a part per million. So Galilean relativity predicts
> each proton has a a kinetic energy (0.5*m*v^2) of 7.5E-11 Joule. The
> actual measurement of 6 TeV corresponds to 9.6E-7 Joule, more than 5,000
> sigma from the Galilean prediction. Galilean relativity is completely
> and utterly WRONG.

> Tom Roberts

Hi Tom Roberts
Do you know well Cern and accelerator? When the protons are accelerated, do they come closer to each other? If yes, the frequency of passing of the protons will be higher when the speed is higher.

PK

[Ned Latham]

Tom Roberts wrote:
> Ned Latham wrote:
> > Tom Roberts wrote:
> > >
> > > Given the properties of inertial frames, there are
> > > only three possible transformation groups that can
> > > relate the coordinates of one frame to those of
> > > another: Euclid, Galilei, and Lorentz. Of them, only
> > > the Lorentz group agrees with experiments (locally).
> >
> > False. Galileian transforms agrree with experiments within
> > the limits of experiemtal error,
>
> This is just plain not true. The tens of thousands of particle
> accelerators around the world refute Galilean relativity every day.

False.

[Odd Bodkin]

Ned Latham <nedl...@woden.valhalla.oz> wrote:
> Tom Roberts wrote:
>> Ned Latham wrote:
>>> Tom Roberts wrote:
>>>>
>>>> Given the properties of inertial frames, there are
>>>> only three possible transformation groups that can
>>>> relate the coordinates of one frame to those of
>>>> another: Euclid, Galilei, and Lorentz. Of them, only
>>>> the Lorentz group agrees with experiments (locally).
>>>

>>> False. Galileian transforms agrree with experimentse within

>>> the limits of experiemtal error,
>>
>> This is just plain not true. The tens of thousands of particle
>> accelerators around the world refute Galilean relativity every day.
>
> False.
>

How’s the research going on the data points from accelerators to inform
your vague field energy function?

--
Odd Bodkin — Maker of fine toys, tools, tables

[Ned Latham]

Odd Bodkin wrote:
> Ned Latham wrote:
> > Tom Roberts wrote:
> > > Ned Latham wrote:
> > > > Tom Roberts wrote:
> > > > >
> > > > > Given the properties of inertial frames, there are
> > > > > only three possible transformation groups that can
> > > > > relate the coordinates of one frame to those of
> > > > > another: Euclid, Galilei, and Lorentz. Of them, only
> > > > > the Lorentz group agrees with experiments (locally).
> > > >
> > > > False. Galileian transforms agrree with experimentse within
> > > > the limits of experiemtal error,
> > >
> > > This is just plain not true. The tens of thousands of particle
> > > accelerators around the world refute Galilean relativity every
> > > day.
> >
> > False.
>
> How's the research going on the data points from accelerators to inform
> your vague field energy function?

How's your denial of facts in the "What i am, is a radical cosmologist"
thread coming along?

[Tom Roberts]

On 3/4/20 4:55 PM, PengKuan Em wrote:
> Le mercredi 4 mars 2020 22:03:02 UTC+1, tjrob137 a écrit :
>> Here's a simple example: At CERN the LHC accelerates protons to a
>> kinetic energy of 6 TeV, measured with an accuracy about 200 parts per
>> million. Their speed is measured to be 299792000 m/s, measured with an
>> accuracy better than 1 part per million. The proton mass is known to
>> much better than a part per million. So Galilean relativity predicts
>> each proton has a a kinetic energy (0.5*m*v^2) of 7.5E-11 Joule. The
>> actual measurement of 6 TeV corresponds to 9.6E-7 Joule, more than 5,000
>> sigma from the Galilean prediction. Galilean relativity is completely
>> and utterly WRONG.
>

> Do you know well Cern and accelerator?

I know the basics, and I have been there, but am not expert on the details.

> When the protons are accelerated, do they come closer to each other?

Offhand I don't know. Google is your friend -- look up "bunch length". A
bunch is the collection of protons that occupy a single cycle of the
accelerating RF. It's the smallest subdivision of the beam.

But don't deceive yourself into thinking this is "length contraction",
because longitudinal focusing is far more important. So the answer
depends on how the machines were designed.

I suspect they designed the machines so the bunches do get shorter,
because the bunch length must be shorter than \beta* at the
intersection, to avoid luminosity reduction due to the "hourglass
effect". Moreover, \beta* must be as small as possible to maximize the
luminosity.

Luminosity is a measure of how frequently the particle
beams will interact. It is proportional to the rate of
interesting events, so machine designers always maximize
it, subject to the physical constraints and budget.

\beta* is a measure of the transverse focusing at the
beam intersection, expressed in meters. Smaller values
mean more focusing and higher luminosity.

The interval between bunches could also be interpreted as the subject of
your question. Once the protons reach a few GeV in energy, the interval
between bunches does not change appreciably, all the way up to 6 TeV.

> If yes, the frequency of passing of the protons will be higher when the speed is higher.

That's merely what "closer" means, in this context.

Tom Roberts

[Tom Roberts]

Bare assertions carry no weight.

Tom Roberts

[Odd Bodkin]

I may have missed a point you attempted to make.

[Ned Latham]

The whole post, actually.

[Ned Latham]

Tom Roberts wrote:
> Ned Latham wrote:
> > Tom Roberts wrote:
> > >
> > > The tens of thousands of particle
> > > accelerators around the world refute Galilean relativity every day.
> >
> > False.
>
> Bare assertions carry no weight.

Yours included.

[Tom Roberts]

I have given you many responses with technical details. They are easily
substantiated by elementary physics textbooks and/or the physics
literature. In particular, my recent example of proton energy in the LHC
is a clear and obvious refutation of your claims. It is not a "bare
assertion", it is a cogent calculation based on readily accessible
information.

You dismiss all references to modern physics, apparently because they do
not conform to your personal prejudices that you call a "theory".

[Ned Latham]

Tom Roberts wrote:
> Ned Latham wrote:
> > Tom Roberts wrote:
> > > Ned Latham wrote:
> > > > Tom Roberts wrote:
> > > > >
> > > > > The tens of thousands of particle
> > > > > accelerators around the world refute Galilean relativity every day.
> > > >
> > > > False.
> > >
> > > Bare assertions carry no weight.
> >
> > Yours included.
>
> I have given you many responses with technical details.

Yair. Like the idiocy above. Reiforced with claims of "thousands"
of sigma.

Try for something credible.

[pnal...@gmail.com]

Do you need to practice to be so insular, Ned, or does it just come naturally?

[maluw...@gmail.com]

Bullshit, of course. Galilean relativity predicts nothing
like that.

The
> actual measurement of 6 TeV corresponds to 9.6E-7 Joule, more than 5,000
> sigma from the Galilean prediction. Galilean relativity is completely
> and utterly WRONG.

No, poor idiot. You're just lying about what it
predicts, as expected from a fanatic idiot.

[Ned Latham]

pnalsing wrote:
> Ned Latham wrote:
> > Tom Roberts wrote:
> > > Ned Latham wrote:
> > > > Tom Roberts wrote:
> > > > > Ned Latham wrote:
> > > > > > Tom Roberts wrote:
> > > > > > >
> > > > > > > The tens of thousands of particle accelerators around
> > > > > > > the world refute Galilean relativity every day.
> > > > > >
> > > > > > False.
> > > > >
> > > > > Bare assertions carry no weight.
> > > >
> > > > Yours included.
> > >
> > > I have given you many responses with technical details.
> >
> > Yair. Like the idiocy above. Reiforced with claims of "thousands"
> > of sigma.
> >
> > Try for something credible.
>
> Do you need to practice to be so insular,
> Ned, or does it just come naturally?

"Insular", Dumbfuck? You *do* have a problem with English.

Who'd a thunk it?

[PengKuan Em]

Le jeudi 5 mars 2020 03:11:47 UTC+1, tjrob137 a écrit :
> Offhand I don't know. Google is your friend -- look up "bunch length". A
> bunch is the collection of protons that occupy a single cycle of the
> accelerating RF. It's the smallest subdivision of the beam.
>

> The interval between bunches could also be interpreted as the subject of
> your question. Once the protons reach a few GeV in energy, the interval
> between bunches does not change appreciably, all the way up to 6 TeV.
>
> > If yes, the frequency of passing of the protons will be higher when the speed is higher.
>
> That's merely what "closer" means, in this context.
>
> Tom Roberts

"bunch length" is a very useful information. Thank you.

So, the distance between 2 bunches stays constant when accelerated. At suppose 1 tev this distance is l, at 6 tev, this distance should be shorter by contraction l/a, but it is not. If contracted, the bunches should gather closer as Figure 7 in my article shows. But they actually are as the Figure 8 show, evenly spaced.
https://www.academia.edu/42129223/Time_relativity_transformation_of_coordinates
https://pengkuanonphysics.blogspot.com/2020/03/time-relativity-transformation-of.html

PK

[Tom Roberts]

On 3/5/20 8:41 AM, PengKuan Em wrote:
> So, the distance between 2 bunches stays constant when accelerated.
> At suppose 1 tev this distance is l, at 6 tev, this distance should
> be shorter by contraction l/a,

No. As I said, longitudinal focusing is MUCH more important than "length
contraction". The accelerating E field in the RF cavities pushes the
bunches around so their interval is constant, because the RF frequency
is constant. Beam bunches are collections of many individual particles,
and most definitely are NOT rigid objects.

Longitudinal focusing is what keep the particles in the
bunch. The phase of the RF is arranged so individual
particles with energy higher than average see less
acceleration, and individual particles with energy less
than average see more acceleration.

Remember that "length contraction" is related to relatively-moving
frames, and does not consider any forces on the objects involved. Here
the RF cavities exert very strong forces on the particles in each bunch.

Note I am discussing bunch length and bunch interval measured in the lab.

Tom Roberts

[pnal...@gmail.com]

On Thursday, March 5, 2020 at 1:05:02 AM UTC-8, Ned Latham wrote:

> pnalsing wrote:

> > Do you need to practice to be so insular,
> > Ned, or does it just come naturally?
>
> "Insular", Dumbfuck? You *do* have a problem with English.

Just because *you* don't know the meaning of the word does not mean that it isn't applicable...

[PengKuan Em]

Le jeudi 5 mars 2020 18:06:57 UTC+1, tjrob137 a écrit :
> On 3/5/20 8:41 AM, PengKuan Em wrote:
> > So, the distance between 2 bunches stays constant when accelerated.
> > At suppose 1 tev this distance is l, at 6 tev, this distance should
> > be shorter by contraction l/a,
>
> No. As I said, longitudinal focusing is MUCH more important than "length
> contraction". The accelerating E field in the RF cavities pushes the
> bunches around so their interval is constant

Do you mean that length contraction can be canceled by EM force? Because of the “The accelerating E field”, length contraction does not exists?

>
> Remember that "length contraction" is related to relatively-moving
> frames, and does not consider any forces on the objects involved. Here
> the RF cavities exert very strong forces on the particles in each bunch.
>
> Note I am discussing bunch length and bunch interval measured in the lab.
>
> Tom Roberts

But why “Remember that "length contraction" is related to relatively-moving frames and does not consider any forces on the objects involved?”
EM force is involved, this is why no length contraction is seen, isn’t it?

“ … bunch length and bunch interval measured in the lab”. Yes. If in the lab, length is constant, then in the frame of the bunch, the length is several times longer.

PK

[Odd Bodkin]

Quite. If I stop paying attention to you, your posts disappear, by setting.
That’s deliberate.

[Tom Roberts]

On 3/5/20 2:00 PM, PengKuan Em wrote:
> Le jeudi 5 mars 2020 18:06:57 UTC+1, tjrob137 a écrit :
>> On 3/5/20 8:41 AM, PengKuan Em wrote:
>>> So, the distance between 2 bunches stays constant when
>>> accelerated. At suppose 1 tev this distance is l, at 6 tev, this
>>> distance should be shorter by contraction l/a,
>>
>> No. As I said, longitudinal focusing is MUCH more important than
>> "length contraction". The accelerating E field in the RF cavities
>> pushes the bunches around so their interval is constant

Hmmm. I should have said that the RF cavities determine the bunch length
and interval in the lab, so "length contraction" is irrelevant -- we
don't know the bunch length or interval in their rest frame, and don't care.

> Do you mean that length contraction can be canceled by EM force?
> Because of the “The accelerating E field”, length contraction does
> not exists?

No to both.

But you have to remember what "length contraction" is, AND WHAT IT
ISN'T. In particular, it is a geometrical relationship, and is not any
kind of force. There is no way to "cancel" it.

If you have an object OF KNOWN LENGTH, and you measure it from a frame
moving relative to it, you get a value smaller than its intrinsic
length. That is "length contraction" -- it is an artifact of how you
measured, and the object itself is of course unchanged.

But here we don't know the length of a bunch in its rest frame, nor do
we know the distance between bunches in their rest frame. Instead we
have an apparatus (RF cavities) at rest in the lab that dynamically
imposes a bunch length and bunch interval onto the beam, in the lab. So
the only way to apply "length contraction" is to determine the unknown
length and interval of the bunches in their rest frame -- which are
useless as nobody cares.

Remember a particle beam is not a single object, it is
a collection of many, many particles and is not at all
rigid. It is far more evanescent than a cloud.

The geometrical relationships of "length contraction" are always present
between relatively-moving frames. But applying them to a given physical
situation requires that the situation conform to what "length
contraction" can tell you, and here it only tells you useless information.

> “ … bunch length and bunch interval measured in the lab”. Yes. If in
> the lab, length is constant, then in the frame of the bunch, the
> length is several times longer.

Yes, but for 6 TeV protons your "several" is a gross understatement as
the ratio is > 6,000.

Tom Roberts

[Ned Latham]

Odd Bodkin wrote:
> Ned Latham wrote:
> > Odd Bodkin wrote:
> > > Ned Latham wrote:
> > > > Odd Bodkin wrote:
> > > > > Ned Latham wrote:
> > > > > > Tom Roberts wrote:
> > > > > > > Ned Latham wrote:
> > > > > > > > Tom Roberts wrote:
> > > > > > > > >
> > > > > > > > > Given the properties of inertial frames, there are
> > > > > > > > > only three possible transformation groups that can
> > > > > > > > > relate the coordinates of one frame to those of
> > > > > > > > > another: Euclid, Galilei, and Lorentz. Of them, only
> > > > > > > > > the Lorentz group agrees with experiments (locally).
> > > > > > > >

> > > > > > > > False. Galileian transforms agrree with experiments within

> > > > > > > > the limits of experiemtal error,
> > > > > > >
> > > > > > > This is just plain not true. The tens of thousands of
> > > > > > > particle accelerators around the world refute Galilean
> > > > > > > relativity every day.
> > > > > >
> > > > > > False.
> > > > >
> > > > > How's the research going on the data points from accelerators
> > > > > to inform your vague field energy function?
> > > >
> > > > How's your denial of facts in the "What i am, is a radical
> > > > cosmologist" thread coming along?
> > >
> > > I may have missed a point you attempted to make.
> >
> > The whole post, actually.
>
> Quite. If I stop paying attention to you, your posts disappear, by
> setting. That's deliberate.

Larf. They don't disappear, Slow Boy. They're still there, and all you
can do is make excuses for your inability to face the facts.

[Mitch Raemsch]

Slow time and fast time are absolute and space and size do not contract...
the hypersphere size does not shrink...

[Odd Bodkin]

Of course they are. But I don’t scour things that are off my active feed
unless I have a reason to. And since your posts go off my active feed by
setting, and I have no reason to go looking for them, then I don’t.

That’s not an excuse. It’s a deliberate practice for your posts.

> and all you
> can do is make excuses for your inability to face the facts.
>

[Ned Latham]

> > Larf. They don't disappear, Slow Boy. They're still there, and all

> > you can do is make excuses for your inability to face the facts.
>

> Of course they are. But I don't scour things that are off my active
> feed unless I have a reason to. And since your posts go off my active
> feed by setting, and I have no reason to go looking for them, then I
> don't.

One would think that facing the facts would actually be simpler than
your elaborate evasions and excusemaking. Yet here you are still
answering my posts, still evading the facts, and still making excuses.

[Odd Bodkin]

I choose when to ridicule you and when to ignore you.

[Ned Latham]

Say that often enough, Slow Boy, and you just might manage to convince
yourself.

[Odd Bodkin]

No convincing needed, Ned. I know why I do things.

[Ned Latham]

Odd Bodkin wrote:
> Ned Latham wrote:
> > Odd Bodkin wrote:
> > > Ned Latham wrote:

----snip----

> > > > One would think that facing the facts would actually be
> > > > simpler than your elaborate evasions and excusemaking.
> > > > Yet here you are still answering my posts, still evading
> > > > the facts, and still making excuses.
> > >
> > > I choose when to ridicule you and when to ignore you.
> >
> > Say that often enough, Slow Boy, and you just might manage to
> > convince yourself.
>
> No convincing needed, Ned. I know why I do things.

LOL. Say that often enough, Slow Boy, and you just might manage to
convince yourself.

[PengKuan Em]

Le jeudi 5 mars 2020 22:42:01 UTC+1, tjrob137 a écrit :
> Hmmm. I should have said that the RF cavities determine the bunch length
> and interval in the lab, so "length contraction" is irrelevant -- we
> don't know the bunch length or interval in their rest frame, and don't care.
>

> But here we don't know the length of a bunch in its rest frame, nor do
> we know the distance between bunches in their rest frame. Instead we
> have an apparatus (RF cavities) at rest in the lab that dynamically
> imposes a bunch length and bunch interval onto the beam, in the lab. So
> the only way to apply "length contraction" is to determine the unknown
> length and interval of the bunches in their rest frame -- which are
> useless as nobody cares.

“don't know… don't care… which are useless as nobody cares”
Do these words mean that "length contraction" does not exist?

> The geometrical relationships of "length contraction" are always present
> between relatively-moving frames. But applying them to a given physical
> situation requires that the situation conform to what "length
> contraction" can tell you, and here it only tells you useless information.

“The geometrical relationships of "length contraction" are always present between relatively-moving frames.”
If it exists, can we question what is it? Even it is “useless information”?

>
> Yes, but for 6 TeV protons your "several" is a gross understatement as
> the ratio is > 6,000.
>
> Tom Roberts

Wow, 6000 times means the distance in the frame of the bunches is 162000 km long, squeezed into 27 km of LHC tunnel.

Does “don't know… don't care… useless as nobody cares” mean that relativity is useless for the 27 km of LHC tunnel?

PK

[Tom Roberts]

On 3/6/20 6:33 AM, PengKuan Em wrote:
> Le jeudi 5 mars 2020 22:42:01 UTC+1, tjrob137 a écrit :
>> But here we don't know the length of a bunch in its rest frame, nor
>> do we know the distance between bunches in their rest frame.
>> Instead we have an apparatus (RF cavities) at rest in the lab that
>> dynamically imposes a bunch length and bunch interval onto the
>> beam, in the lab. So the only way to apply "length contraction" is
>> to determine the unknown length and interval of the bunches in
>> their rest frame -- which are useless as nobody cares.
>
> “don't know… don't care… which are useless as nobody cares” Do these
> words mean that "length contraction" does not exist?

No! It meas what it says: we do not care what values those quantities
have in the rest frame of the bunch(es). They are of no interest because
all accelerator components are at rest in the lab.

Analogy: I have a ruler sitting at rest on my desk. How does "length
contraction" apply to it if I want to know its properties in the rest
frame of the desk? -- it doesn't.

Yes, the beam bunches are moving relative to the lab. But we only make
measurements IN THE LAB FRAME, and we only care about properties of the
beam bunches IN THE LAB FRAME. There's no need to apply "length
contraction" to measurements made in the lab frame to get results
relative to the lab frame.

Feel free to apply "length contraction" to those lab-frame measurements
to obtain values in the beam frame. But we will all ignore them.

>> for 6 TeV protons the ratio is > 6,000.

>
> Wow, 6000 times means the distance in the frame of the bunches is
> 162000 km long, squeezed into 27 km of LHC tunnel.

You need to remember what SR is, and how it applies, AND HOW IT DOES NOT
APPLY. The beam is MOVING AROUND A CIRCLE, so there is no "rest frame of
the bunches" (because "frame" implicitly implies inertial frame).

You can apply 'length contraction" to a lab measurement of the length of
a bunch, to obtain the length of the bunch in the beam frame, as long as
the measurement is made at one place around the ring, in a region with
no EM field; The result applies ONLY AT THAT PLACE. That does not work
all the way around the ring, it only works at one place, because at that
place the beam is moving inertially (no EM field).

> Does “don't know… don't care… useless as nobody cares” mean that
> relativity is useless for the 27 km of LHC tunnel?

Not at all! It means that applying "length contraction" from lab to beam
frame is useless, because it only gives information that is never used.
Other aspects of SR are essential to the design and operation of the LHC
(and most other particle accelerators). For instance the relationship
between proton energy and proton velocity is essential to designing the
RF cavities; there are LOTS more examples.

You really need to learn about relativity; get a good textbook and STUDY.

Tom Roberts

[Thomas 'PointedEars' Lahn]

Tom Roberts wrote:

> Here's a simple example: At CERN the LHC accelerates protons to a
> kinetic energy of 6 TeV, measured with an accuracy about 200 parts per
> million. Their speed is measured to be 299792000 m/s, measured with an
> accuracy better than 1 part per million. The proton mass is known to
> much better than a part per million. So Galilean relativity predicts

> each proton has a a kinetic energy (0.5*m*v^2) of 7.5E-11 Joule. The

> actual measurement of 6 TeV corresponds to 9.6E-7 Joule, more than 5,000
> sigma from the Galilean prediction. Galilean relativity is completely
> and utterly WRONG.

Exactly. Another way that I find even more convincing that also uses this
example is to calculate the speed of proton (bunches) from the collision
energy. It currently is 13 TeV (so _6.5_ TeV total energy per proton).

Galilean relativity and Newtonian mechanics tell us that the kinetic energy
(which in the absence of potential energy is the total mechanical energy)
of such a proton would be

T = 1/2 m v²,

so its relative speed would be

v = √(2 T/m) ≈ √(2 · 6.5 TeV/mₚ) ≈ 117.7 c.

However, special relativity tells us that the total energy of a massive
particle is actually the sum of its rest energy and kinetic energy, and that
its total energy is given by

E = γ m c² = m c²/√(1 − v²/c²)

So

v = c √(1 − m²c⁴/E²) = c √(1 − mₚ²c⁴/(6.5 TeV)²) ≈ 0.9999999896 c.

The speed measured is the speed predicted by special relativity,
NOT Galilean relativity/Newtonian mechanics.

--
PointedEars
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<https://github.com/PointedEars> | <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | Please do not cc me./Bitte keine Kopien per E-Mail.

[PengKuan Em]

Le vendredi 6 mars 2020 19:07:44 UTC+1, tjrob137 a écrit :

> No! It meas what it says: we do not care what values those quantities
> have in the rest frame of the bunch(es). They are of no interest because
> all accelerator components are at rest in the lab.

> Yes, the beam bunches are moving relative to the lab. But we only make
> measurements IN THE LAB FRAME, and we only care about properties of the
> beam bunches IN THE LAB FRAME. There's no need to apply "length
> contraction" to measurements made in the lab frame to get results
> relative to the lab frame.
>

> Not at all! It means that applying "length contraction" from lab to beam
> frame is useless, because it only gives information that is never used.
> Other aspects of SR are essential to the design and operation of the LHC
> (and most other particle accelerators). For instance the relationship
> between proton energy and proton velocity is essential to designing the
> RF cavities; there are LOTS more examples.
>
> You really need to learn about relativity; get a good textbook and STUDY.
>
> Tom Roberts

I see, you think that length contraction is useless.

But in theory, useless is not enough for not checking the soundness of the fact. Einstein has developed the general relativity from the fact that a rotating disk should have a curvature to explain length contraction of the disk. So, it is very useful for him.

PK

[Michael Moroney]

PengKuan Em <tita...@gmail.com> writes:

>I see, you think that length contraction is useless.

No, he is saying that length contraction is not useful for that specific
case. Just as it is not useful for me to know the color of your shirt to
write this post. It could be useful in a different situation.

[Odd Bodkin]

Air friction is important for bicycle designers. Not for sewing machines.

[Tom Roberts]

On 3/6/20 5:57 PM, PengKuan Em wrote:
> I see, you think that length contraction is useless.

In this case of bunches in a particle accelerator, yes. And in all cases
where measurements are made in the frame in which they will be used -- DUH!

But in other cases, no.

Note that "length contraction" is absolutely required for
self-consistency of the Lorentz group.

> But in theory, useless is not enough for not checking the soundness
> of the fact.

Sure, when possible. With current technology it simply is not possible
to directly measure the "length contraction" of a moving object. But
there are indirect measurements of it, such as:
a) the correspondence between fixed-target and collider
differential cross-sections for elementary particle
interactions
b) the magnetic force of a long, straight, current-carrying wire,
calculated from the Coulomb force and the "length contraction"
of the electrons moving at a few mm/sec relative to the wire

Tom Roberts

[PengKuan Em]

Le samedi 7 mars 2020 06:50:37 UTC+1, tjrob137 a écrit :
> On 3/6/20 5:57 PM, PengKuan Em wrote:
> > I see, you think that length contraction is useless.
>
> In this case of bunches in a particle accelerator, yes. And in all cases
> where measurements are made in the frame in which they will be used -- DUH!
>
> But in other cases, no.
>
> Note that "length contraction" is absolutely required for
> self-consistency of the Lorentz group.

So, even in some situation "length contraction" is not useful, it is real, because “absolutely required for self-consistency of the Lorentz group.”

>
> > But in theory, useless is not enough for not checking the soundness
> > of the fact.
>
> Sure, when possible. With current technology it simply is not possible
> to directly measure the "length contraction" of a moving object. But
> there are indirect measurements of it, such as:
> a) the correspondence between fixed-target and collider
> differential cross-sections for elementary particle
> interactions
> b) the magnetic force of a long, straight, current-carrying wire,
> calculated from the Coulomb force and the "length contraction"
> of the electrons moving at a few mm/sec relative to the wire
>
> Tom Roberts

If "length contraction" is measured, it occurs in all situations even we do not care and cannot measure it. But we can discuss about how it works in these situations, right?

How long is the distance between 2 bunches? Say, 2 bunches are 0.01 degree of a circle apart from one another. If this distance is contracted by half, 2 bunches should be 0.005 degree apart in the frame of the lab. But as the distance between 2 bunches is constant in the frame of the lab, 2 bunches are still 0.01 degree apart. Then, in the frame of the bunches 2 bunches should be 0.02 degree apart. Other way, "length contraction" could not exist.

PK

[PengKuan Em]

Le samedi 7 mars 2020 01:20:55 UTC+1, Michael Moroney a écrit :

yes. Thanks.