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| Jan Panteltje |
 Posted: Wed Apr 30, 2008 2:35 pm |
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On a sunny day (Thu, 1 May 2008 05:14:23 +1000) it happened "Timo A. Nieminen"
<timo@physics.uq.edu.au> wrote in
<Pine.WNT.4.64.0805010459360.1420@serene.st>:
Quote: 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.
Quote: (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.
Quote: and, in the context of
optics, "waves" is "mechanism".
When there are waves, something must wave 
As opposed to 'photon', and other mathematical construct.
Quote: 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.
Quote: which is just a Newtonian-style mathematical-model-only force law.
True.
Quote: Accepting "waves" as mechanism in optics but not "field" in EM is odd,
since classical optics is a special case of electromagnetism, and the
waves in question are electromagnetic waves. "EM field" is not a
mechanism, but "EM waves" are?
Right.
See my definition of 'field' at the start of this posting.
Quote: So, "every time"? Perhaps you'd best define "mechanism".
Quote: 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.
Quote: - where has industry
taken a great flight using that to do things?
Well, plasma physics really is used in lots of places.
Quote: Indeed, you were complaining
about the lack of progress based on the mechanism of nuclear fusion.
Sure, nature presents us with fusion balls (sun etc), while
these guys try to do the doughnut thingy so they have a primary turn
in a transformer.
Can you bend the plasma the way you want [in circles]?
Quote: We know the mechanism of solar sails (it's just reflection of EM waves,
after all) - what great flights has industry achieved?
Sorry I do not understand that remark, it is late here.... |
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| Thomas Heger |
| Posted: Wed Apr 30, 2008 5:13 pm |
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Quote:
OK, but I have read more from the end then the last few.
For a moment it reminded me of some proposition I have seen from some
uni about what conducts EM waves.
Maybe these things are simply over my head...
Sure, there must be something that makes up space....
And it must have very special properties.
But I still think your terminology is perhaps to vague to really hit
'eureka'.
It is indeed more philosophy.
Maybe you concentrate on only one question.
The model is based on a simplification of spacetime. You take only one
spatial dimension and one temporal. In this a light cone is a triangle
pointing up from an event. Now I think about, what make this movement
upwards. That is modelled out of spinning quaternions. Those are special
numbers with three imaginary components and a real scalar part. By those
quaternions you can model rotations. -out of roations i build the whole
spacetime of GR. So those quaternions are supposed to be fundamental
entities. Out of that I build structures that look like atoms. Those behave
more like the atoms we actually observe than those described by
quantumphysics. So there is a different model for atoms. The whole thing is
quite strange, but it is very much like things observed. I can actually
solve most of the top unsolved problems with my model. I checked it on many
problems and it allways worked fine. So I think that it's a good model.
Thomas Heger |
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| Joel Koltner |
| Posted: Wed Apr 30, 2008 8:39 pm |
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"Timothy Golden BandTechnology.com" <tttpppggg@yahoo.com> wrote in message
news:55309afa-4aee-4644-b9fb-c61944d1195e@y38g2000hsy.googlegroups.com...
Quote: 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...)
Quote: 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.
Quote: 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.
Quote: 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 |
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| PD |
| Posted: Thu May 01, 2008 6:07 am |
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On Apr 30, 2:35 pm, Jan Panteltje <PNaonStpealm...@yahoo.com> wrote:
Quote: On a sunny day (Thu, 1 May 2008 05:14:23 +1000) it happened "Timo A. Nieminen"
t...@physics.uq.edu.au> wrote in
Pine.WNT.4.64.0805010459360.1...@serene.st>:
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.
(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.
Semantic clarification. If a model has a boundary of applicability,
that can be called a limitation. But if a theory makes a definite
prediction that is contrary to measurement, that's an indicator it's
*wrong*. Now, the cheesy way out is to say, "OK, so don't make that
prediction with the model." This is theoretical gerrymandering,
generally frowned upon in science.
Quote:
and, in the context of
optics, "waves" is "mechanism".
When there are waves, something must wave
Yes, but it does not need to be a material substance. It can well be a
field.
Quote: As opposed to 'photon', and other 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.
Accepting "waves" as mechanism in optics but not "field" in EM is odd,
since classical optics is a special case of electromagnetism, and the
waves in question are electromagnetic waves. "EM field" is not a
mechanism, but "EM waves" are?
Right.
See my definition of 'field' at the start of this posting.
So, "every time"? Perhaps you'd best define "mechanism".
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.
- where has industry
taken a great flight using that to do things?
Well, plasma physics really is used in lots of places.
Indeed, you were complaining
about the lack of progress based on the mechanism of nuclear fusion.
Sure, nature presents us with fusion balls (sun etc), while
these guys try to do the doughnut thingy so they have a primary turn
in a transformer.
Can you bend the plasma the way you want [in circles]?
We know the mechanism of solar sails (it's just reflection of EM waves,
after all) - what great flights has industry achieved?
Sorry I do not understand that remark, it is late here.... |
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| Timo A. Nieminen |
| Posted: Thu May 01, 2008 3:41 pm |
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On Wed, 30 Apr 2008, Jan Panteltje 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?
Quote: 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?
Quote: (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"?
Quote: 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"?
Quote: 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"?
Quote: 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!
Quote: 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?
Quote: - 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/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
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