On Wed, 30 Apr 2008, Jan Panteltje wrote:

Timo wrote:

Oh, what a surprise! Once again, you simply cut all discussion of your
original claim that "mechanism" is necessary for physics to advance.

Why are you so afraid to discuss what _you_ first claimed?

It might also be useful if you try to define "mechanism". All that I know
about what you mean is that "field" is not "mechanism"

Field is a mathematical concept, it describes the forces we observe.
You may as well write 'ghost'.
It does _not_ tell you how those forces are transmitted, or conveyed if you like.

Oh, what a surprise! Once again, you refuse to even attempt to define what
you mean by "mechanism".

If you really don't want to discuss these topics, why reply? Why, even,
make your original claim? Or do you really believe that what you state
should simply be taken as revealed truth by readers on the ng?

(just in
gravitation, or in electromagnetism as well - you appeared to deny the
sufficiency of "field" in the context of EM, but perhaps you would like to
try to weasel out of this claim now as well), the "little ball" analogy of
electrons is "mechanism" (despite being _wrong_),

It is not wrong, it has limitations, but so has all of physics.

You said yourself "analogy". It clearly doesn't describe all of the
behaviour of electrons. You've also refused to say what quantitative
predictions it can make, and apparently there are none, unless you add, in
the spirit of Newtonianism, mere mathematical models, devoid of mechanism,
to the analogy you call "mechanism".

More seriously, we can tolerate a mathematical model being correct only
within a limited regime - essentially, being wrong in a fundamental sense
- because the mathematical model is not intended to be, is not claimed to
be, is not a fundamental explanation of "why" or "is", but a mathematical
model to describe observed behaviour.

You (again!) refused to explain what you mean by "mechanism", but the
usual meaning is an explanation of "why", something meant to be
fundamentally true. An "explanation" that is known to be fundamentally
_wrong_, an "explanation" that is known to be an easily visualisable
analogy (Perhaps good for the imagination, good for teaching, and so on -
just be careful of trying to use it where it's known to be wrong!) is
_not_ what most people would mean by "mechanism". So, why do you (again)
refuse to try to define what _you_ (uniquely?) mean by "mechanism"?

and, in the context of
optics, "waves" is "mechanism".

When there are waves, something must wave :-)

But how is the wave "mechanism" when the only description - the only
knowledge that we have about it - of what "waves" is "field"?

A wave in a "mathematical construct" qualifies as "mechanism"?

As opposed to 'photon', and other mathematical construct.

Photon: it's mass, momentum, energy, charge, angular momentum, etc, have
been experimentally measured. Photons have been detected, generated,
counted. They are known to not behave like "little balls" all of the time,
but some experiments involving them can be visualised using a "little
ball" analogy. There is a technologically important branch of
engineering/science/industry called "photonics", some of which involves
behaviour where the "little ball" analogy can be useful, but much of which
does not.

Electron: it's mass, momentum, energy, charge, angular momentum, etc, have
been experimentally measured. Photons have been detected, generated,
counted. They are known to not behave like "little balls" all of the time,
but some experiments involving them can be visualised using a "little
ball" analogy. There is a technologically important branch of
engineering/science/industry called "electronics", some of which involves
behaviour where the "little ball" analogy can be useful, but much of which
does not.

Why is the "little ball" electron a "mechanism" (despite being known to be
fundamentally wrong), while "photon" is a mere "mathematical construct"?

This appears odd, since "field" explains more about the interactions
between electrons, and between electrons and positive charges, than the
"little ball" model, which tells you nothing unless you add on Coulomb's
law,

Of course you add that, and its mass, etc.

which is just a Newtonian-style mathematical-model-only force law.

True.

But that's exactly the thing that can make the "little ball" analogy
useful! Thus, the value of Newtonianism!

We know how stars
work (and our "mechanism" is every bit as good as the "little ball" model,
largely consisting of such a "little ball" model)

We know partly how stars work, see the recent paper about quantum_gravity
and black holes by Carlip for example, mentioned here today.

Our mechanism of how stars work explains how stars work better than the
"little ball" analogy explains how electronics works. Where are the
equivalent technological/industrial advances? Are you _sure_ that
"mechanism" always leads to technology?

- where has industry
taken a great flight using that to do things?

Well, plasma physics really is used in lots of places.

Where is fusion, using the mechanism that powers stars?

Do note that terrestrial attempts at fusion power do _not_ use the same
mechanism!

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/...,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html

On a sunny day (Fri, 2 May 2008 06:41:29 +1000) it happened "Timo A. Nieminen"
wrote in :

On Wed, 30 Apr 2008, Jan Panteltje wrote:

Timo wrote:

Oh, what a surprise! Once again, you simply cut all discussion of your
original claim that "mechanism" is necessary for physics to advance.

I did not.
But you carry on about I dunno what.


It might also be useful if you try to define "mechanism". All that I know
about what you mean is that "field" is not "mechanism"

Field is a mathematical concept, it describes the forces we observe.
You may as well write 'ghost'.
It does _not_ tell you how those forces are transmitted, or conveyed if you like.

Oh, what a surprise! Once again, you refuse to even attempt to define what
you mean by "mechanism".

Now, and this is the last time, as it is waste of time discussing this
with those who refuse to, or cannot, understand:

When field is a mathematical concept, a 'mechanism' is something that
shows how the forces are transferred that make up the field.

For example: for gravity you have no such mechanism in main stream physics,
at least no consensus.


If you really don't want to discuss these topics, why reply?

The topic is exactly what you seem to fail to understand.
As others, and the OP, pointed out to you earlier.


But that's exactly the thing that can make the "little ball" analogy
useful! Thus, the value of Newtonianism!

We know how stars
work (and our "mechanism" is every bit as good as the "little ball" model,
largely consisting of such a "little ball" model)

We know partly how stars work, see the recent paper about quantum_gravity
and black holes by Carlip for example, mentioned here today.

Our mechanism of how stars work explains how stars work better than the
"little ball" analogy explains how electronics works. Where are the
equivalent technological/industrial advances? Are you _sure_ that
"mechanism" always leads to technology?

Wrong, apart from the interesting thread in sci.astro 'convection inside a star',
and the contribution of Steve Willner, which you should read,
if you have no mechanism for gravity then you have no mechanism for gravity in stars.
Stars are being studied, and full of mysteries, google SOHO.
New stuff every day, and that is only the sun.



- where has industry
taken a great flight using that to do things?

Well, plasma physics really is used in lots of places.

Where is fusion, using the mechanism that powers stars?

Also you are 'weaselling' (using your own words) away.
You stated nobody would build something that theory proves cannot work.
Well LIGO will never break even, and in confidentiality,
one of the people there told the press that he does not expect break even in a hundred years.
YET THEY STILL BUILD IT.


Sun.
Add solar cells, or focus the heat to make steam.


Do note that terrestrial attempts at fusion power do _not_ use the same
mechanism!

Actually it is the same idea.
Stars can burn many types of fuel, so can we on earth.

On Apr 30, 9:39 pm, "Joel Koltner"
wrote:
"Timothy Golden BandTechnology.com" wrote in ...

That brings me to the puzzle of the self shielding toroidal coil. How
is it that the external magnetic field is negligible?

The idea is that the magnetic field produced (strictly) by the current flowing
in the conductors that completely enclose the toroid produce zero external
field. Certainly in the real world there are wires running up to that toroid
and those wires will contain a field around them. This is probably not
specifically mentioned in the text because (1) it detracts from the problem at
hand (determining the fields inside and outside of the toroid), (2) actually
computing the fields at the junction between, say, some twisted pair of wires
that then diverge and encircle the toroid is a highly non-trivial problem that
probably can't be solved analytically (look up the papers on calculating the
fields in something as "simple" as a step change in the width of a microstrip
transmission line and you'll get a field for what you're up against), (3) the
field from the wires leading up to the toroid will generally be quite small in
comparison to those inside of it and hence can be neglected, and (4) some
authors probably figure this would all be self-evident.

(Note that authors usually do explicitly mention "feed" concerns when they're
dealing with devices intended to create significant external fields, such as
antennas. Pretty much every discussion of dipole antennas, for instance,
contains at least a little bit about how you need to be careful in arranging
the feed...)

I suppose that this puzzle
has been around with ordinary transformers as well, it's just that
visualizing all of that flux whirring around in the toroid is far
prettier.

The other thing is that, by design, transformers are controlling where almost
all of the flux goes (the bit that "gets away" is leakage, and there's plenty
of discussion on designing transformers to minimize it), whereas with "random
wiring" there's no such control and it's difficult to make accurate
predictions. There are common middle grounds, though, such as microstrip
lines and twisted-pair wiring where -- while the field does extend off to
infinity -- you can still draw reasonably accurate pictures of what's going on
in regions close to the conductors.

If the flux did travel through air for even a portion of its trip then
the remarkable permeabilities of any core xformer would be corrupted.

Um, no, it just creates leakage inductance, which primarily serves to limit
frequency response and decrease the transformer's efficiency.

If that flux that would have travelled through air went into the core
then it would cancel out any induced magnetic field.

Not in the general case... fields are vector quantities, so unless you can get
the magnitudes and directions to line up exactly the right way (like a
reversed secondary coil on a transformer does), the fields don't cancel.

---Joel


Thanks Joel for the detailed response. But I don't feel that my
concern has been sufficiently quashed. Still, I really like the
details that you've gone into. Magnetism does seem to get complicated
quickly when real world materials are used.

But lets just focus on a current carrying wire and the circular loop
of flux that supposedly exists around that wire. Vector, yes, but also
with this loop concept supposedly unbreakable. Now when we bring a
little dl of wire up against a toroidal core we should still see half
of its magnetic loop passing through the air. This has nothing to do
with effects of the leads. If we allow all of the flux to enter the
core then we have broken the basic model of the wire and loop of
flux.

Is there actually leakage around a toroidal coil neglecting the leads?
We see a beautiful clean inner circular path and tend to visualize all
of the flux travelling that inner path, but it had to get there from
the wire so for every line of flux inside doesn't there have to be as
much travelling outside?

Another way of getting to a theoretical conflict is to consider that
when a gap is introduced into a core (which I've read is done to keep
a flat frequency response for low frequency inductors) then that gap
becomes the controlling factor. Don't we really see an air gap for
every line of flux when we come back to studying a differential piece
of the winding? Even for the non-gapped toroidal core I do see that
this is true. Worst of all half of the flux path is through air so we
observe this conflict unless the winding is completely immersed as
with a 'pot' core.

How can we be comfortable with the closed flux path in the toroid? It
goes against theory more than it goes against the toroidal coil. I
must be oversimplifying something. To stay with theory it should
probably be that the flux within the core itself is induced flux and
so those lines of flux should not be confused with the lines of flux
of the wire. This then sets up an extremely high impedance to the
wire's own flux which I guess causes the radius of that flux to be
extremely small. So then we would admit that there is leakage but that
it is small. Is this a clean analysis? I think if it is then alot of
sources may be oversimplifying.

Even the air core coil is inducing those lines of flux of its solenoid
form. It may be that even the loops of flux around the differential
piece of current carrying wire are merely induced. Could this
reasoning take us all the way down to the electron? Perhaps.

- Tim

On Fri, 2 May 2008, Jan Panteltje wrote:

Timo wrote:
On Wed, 30 Apr 2008, Jan Panteltje wrote:
Timo wrote:

Oh, what a surprise! Once again, you simply cut all discussion of your
original claim that "mechanism" is necessary for physics to advance.

I did not.
But you carry on about I dunno what.

I'm discussing _your_ claim that "without mechanism, physics will not
advance". From a historical perspective, including modern advances in
physics, it's clearly false (unless you use a very interesting definition
of "mechanism") - far from stopping all advances in physics, Newtonianism
led to rapid advances in physics, and it appears to have done this in
large part by rejecting the necessity of mechanism.

It might also be useful if you try to define "mechanism". All that I know
about what you mean is that "field" is not "mechanism"

Field is a mathematical concept, it describes the forces we observe.
You may as well write 'ghost'.
It does _not_ tell you how those forces are transmitted, or conveyed if you like.

Oh, what a surprise! Once again, you refuse to even attempt to define what
you mean by "mechanism".

Now, and this is the last time, as it is waste of time discussing this
with those who refuse to, or cannot, understand:

When field is a mathematical concept, a 'mechanism' is something that
shows how the forces are transferred that make up the field.

For example: for gravity you have no such mechanism in main stream physics,
at least no consensus.

That isn't a definition. For a start, the little ball analogy of electrons
doesn't tell you anything about how forces are transferred, and yet you
call it "mechanism". We don't know that "forces make up the field". At the
most, you have given two particular examples, both of force fields, and
indicated that a "mechanism" would show how forces are transferred. It
says nothing about "mechanism" in any other physical theory.

In particular, you might like to clarify why "photon" is a "mathematical
construct" and "electron" is a "mechanism", when:

Photon: it's mass, momentum, energy, charge, angular momentum, etc, have
been experimentally measured. Photons have been detected, generated,
counted. They are known to not behave like "little balls" all of the time,
but some experiments involving them can be visualised using a "little
ball" analogy. There is a technologically important branch of
engineering/science/industry called "photonics", some of which involves
behaviour where the "little ball" analogy can be useful, but much of which
does not.

Electron: it's mass, momentum, energy, charge, angular momentum, etc, have
been experimentally measured. Photons have been detected, generated,
counted. They are known to not behave like "little balls" all of the time,
but some experiments involving them can be visualised using a "little
ball" analogy. There is a technologically important branch of
engineering/science/industry called "electronics", some of which involves
behaviour where the "little ball" analogy can be useful, but much of which
does not.

Why is the "little ball" electron a "mechanism" (despite being known to be
fundamentally wrong), while "photon" is a mere "mathematical construct"?

Why is "EM waves" a "mechanism" but "EM field" is not.

I certainly wouldn't call "photon" or "EM field" a mechanism. But I also
wouldn't call "electron" or "EM waves" a fundamental mechanism either. We
don't know what an electron "is" - all we have is observed behaviour and a
predictive mathematical model. "EM waves" is just a special case of the
behaviour of "EM fields" - how can the former be "mechanism" when we don't
know (as the OP noted) what fields "are"?

Do you mean anything more by "mechanism" than "confortably visualisable
analogy"? How can a comfortable visualisable analogy, especially one known
to be wrong (as in we know electrons do things that _cannot_ be described
in terms of the little ball analogy), be a fundamental explanation?

The topic is exactly what you seem to fail to understand.
As others, and the OP, pointed out to you earlier.

I understand the topic, I understand (and disagree with) your claim (note,
_your_ claim, not the OP's claim. I agree with the OP's (and your) claim
that "field" is not a mechanism. Clearly, classical electromagnetic field
theory is a mathematical model of the behaviour of electromagnetic charges
and currents, not a "fundamental explanation".

Our mechanism of how stars work explains how stars work better than the
"little ball" analogy explains how electronics works. Where are the
equivalent technological/industrial advances? Are you _sure_ that
"mechanism" always leads to technology?

Wrong, apart from the interesting thread in sci.astro 'convection
inside a star',
and the contribution of Steve Willner, which you should read,
if you have no mechanism for gravity then you have no mechanism for
gravity in stars.
Stars are being studied, and full of mysteries, google SOHO.
New stuff every day, and that is only the sun.

So what? Why isn't the (quite successful) "little ball" model of fusion
reactions in the solar core a "mechanism"?

If it isn't a mechanism, then we know a remarkable amount about how stars
work in the absence of a mechanism, and advances in physics are clearly
possible without mechanism.

If it is a mechanism, where is the technology that it has led to?

You're the one making the absolute claims, that physics will not advance
without "mechanism", and that "mechanism" will _always_ lead to
technology. Why don't you try to defend your position with logic and
evidence instead of cut-and-ignore of questions you wish to avoid,
repetition, and the introduction of basically irrelevant points.

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/...,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html