| |
 |
|
| Science Forum Index » Physics Forum » Basis for magnetic monopoles |
|
Page 3 of 7 Goto page Previous 1, 2, 3, 4, 5, 6, 7 Next |
|
| Author |
Message |
| John Schoenfeld |
 Posted: Thu Jun 03, 2004 5:01 pm |
|
|
|
Guest
|
Richard Herring <junk@[127.0.0.1]> wrote in message news:<po3i2pa7mxvAFwUB@baesystems.com>...
[quote:1af75b7dc0]In message <a98beaaa.0406021802.20b74de4@posting.google.com>, John
Schoenfeld <j.schoenfeld@programmer.net> writes
"Robert J. Kolker" <robert_kolker@hotmail.com> wrote in message
news:<aSrvc.37813$eY2.10359@attbi_s02>...
John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
It will have to do. The only magenetic fields that have been seen are
solenoidal and at right angles to the current. If someone does come up
with a magnetic monople Maxwells's Equations will have to be altered.
I don't see why they would require alteration since the equations are
considering only the special case of steady currents
Really? Which part of Maxwell's equations implies steady current?
[/quote:1af75b7dc0]
I meant charges in motion, forgetting the reserved words steady current. |
|
|
| Back to top |
|
|
|
| Timo Nieminen |
| Posted: Thu Jun 03, 2004 5:02 pm |
|
|
|
Guest
|
On Thu, 3 Jun 2004, greywolf42 wrote:
[quote:d06011ba77]Gregory L. Hansen <glhansen@steel.ucs.indiana.edu> wrote:
John Schoenfeld <j.schoenfeld@programmer.net> wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
There's no theoretical reason to prohibit magnetic monopoles. It's an
experimental matter.
An utter falsehood. Maxwell's derivation of Maxwell's equations (On
Physical Lines of Force, 1861) explicitly prohibits magnetic monopoles.
Find a magnetic monopole, and disprove Maxwell's aether!
[/quote:d06011ba77]
Maxwell's ether is already disproved, by the experimental observation of
symmetry under Lorentz transformations.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
|
|
| Back to top |
|
|
|
| Timo Nieminen |
| Posted: Thu Jun 03, 2004 11:44 pm |
|
|
|
Guest
|
On Fri, 4 Jun 2004 mmeron@cars3.uchicago.edu wrote:
[quote:19cfdfafc0]Timo Nieminen <timo@physics.uq.edu.au> writes:
On Fri, 4 Jun 2004, Gregory L. Hansen wrote:
There's a reason Jackson is a classic. And there's a reason he's loathed
by students everywhere.
Education through pain. Effective, if unpleasant. Only the cruel will
inflict Jackson as a textbook. (The truly evil will use L&L.)
Well, I had Jackson as a textbook (and yes, it was painful). As for
L&L, you got to draw a line somewhere:-) You wait till the students
believe that they mastered the topic, then you hit them with L&L.
Teaches humility.
[/quote:19cfdfafc0]
I never copped Jackson as a textbook. But then, I can't say that I learned
EM theory as a student, either. Well, I certainly crammed enough to pass
undergraduate/graduate EM exams (better than some other subjects, even),
but when the time came to actually make use of some of it, I had to
relearn it all.
Then when the time came to teach it, I had to relearn it all again. My
experiences with Jackson in the course of this learning led me to not use
it as a textbook for my students.
And, wow! Parts of L&L have become comprehensible!
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
|
|
| Back to top |
|
|
|
| Guest |
| Posted: Thu Jun 03, 2004 11:57 pm |
|
|
|
|
In article <Pine.LNX.4.50.0406041536520.18056-100000@localhost>, Timo Nieminen <timo@physics.uq.edu.au> writes:
[quote:00a5fad038]On Fri, 4 Jun 2004 mmeron@cars3.uchicago.edu wrote:
Timo Nieminen <timo@physics.uq.edu.au> writes:
On Fri, 4 Jun 2004, Gregory L. Hansen wrote:
There's a reason Jackson is a classic. And there's a reason he's loathed
by students everywhere.
Education through pain. Effective, if unpleasant. Only the cruel will
inflict Jackson as a textbook. (The truly evil will use L&L.)
Well, I had Jackson as a textbook (and yes, it was painful). As for
L&L, you got to draw a line somewhere:-) You wait till the students
believe that they mastered the topic, then you hit them with L&L.
Teaches humility.
I never copped Jackson as a textbook. But then, I can't say that I learned
EM theory as a student, either. Well, I certainly crammed enough to pass
undergraduate/graduate EM exams (better than some other subjects, even),
but when the time came to actually make use of some of it, I had to
relearn it all.
[/quote:00a5fad038]
Pretty much same here. First pass was good enough to get grades and
learn the terminology. Then, I had few free months on my hands, while
babysitting some bridges, and I went through all of Jackson again, at
leisure. Made much better sense the second time around. And then,
couple years later, I TAed from it.
[quote:00a5fad038]
Then when the time came to teach it, I had to relearn it all again. My
experiences with Jackson in the course of this learning led me to not use
it as a textbook for my students.
And, wow! Parts of L&L have become comprehensible!
Eventually, they do. Takes time, though.[/quote:00a5fad038]
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same" |
|
|
| Back to top |
|
|
|
| Richard Herring |
| Posted: Fri Jun 04, 2004 3:18 am |
|
|
|
Guest
|
In message <a98beaaa.0406031501.6f8f9de9@posting.google.com>, John
Schoenfeld <j.schoenfeld@programmer.net> writes
[quote:f109caa783]Richard Herring <junk@[127.0.0.1]> wrote in message
news:<po3i2pa7mxvAFwUB@baesystems.com>...
In message <a98beaaa.0406021802.20b74de4@posting.google.com>, John
Schoenfeld <j.schoenfeld@programmer.net> writes
"Robert J. Kolker" <robert_kolker@hotmail.com> wrote in message
news:<aSrvc.37813$eY2.10359@attbi_s02>...
John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
It will have to do. The only magenetic fields that have been seen are
solenoidal and at right angles to the current. If someone does come up
with a magnetic monople Maxwells's Equations will have to be altered.
I don't see why they would require alteration since the equations are
considering only the special case of steady currents
Really? Which part of Maxwell's equations implies steady current?
I meant charges in motion, forgetting the reserved words steady current.
[/quote:f109caa783]
Sense no makes that.
--
Richard Herring |
|
|
| Back to top |
|
|
|
| John Schoenfeld |
| Posted: Fri Jun 04, 2004 9:45 am |
|
|
|
Guest
|
Timo Nieminen <timo@physics.uq.edu.au> wrote in message news:<Pine.LNX.4.50.0406040829330.17435-100000@localhost>...
[quote:72bd68a549]On Fri, 3 Jun 2004, John Schoenfeld wrote:
Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 2 Jun 2004, John Schoenfeld wrote:
Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 2 Jun 2004, John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields?
No. See, for example, Jackson, Classical electrodynamics, 3rd ed, section
6.11.
div B = 0 is an experimental observation.
Yes an observation from steady currents.
No. It's from observations of steady currents, slowly-varying currents,
rapidly varying currents, and zero currents.
I meant "charges in motion".
You wrote "steady currents". Exactly what do you mean? In any case,
div B = 0 is observed with moving charges, stationary charges,
accelerating charges, and in the absence of charge.
[/quote:72bd68a549]
Yes, hence "charges in motion". And Magnetic fields occur in the
absence of charge? Or are you trying to say that the divergence of a
non-existent field is 0?
[quote:72bd68a549]Note also that the necessary modifications to the Maxwell equations if
magnetic monopoles are found have been known for a long time. 1931 if not
earlier (possibly much earlier).
My question is _why_ would the Maxwell equations require
modifications? If a premise of a theory is that charges in motion
cause solenoidal magnetic fields, then even if magnetic charge can
exist in some other way, why would this the theory require alteration
since the original premise remains valid?
If magnetic charge is found, then you no longer have div B = 0.
Since div B = 0 is one of the Maxwell equations, then the Maxwell
equations require modification.
[/quote:72bd68a549]
Read properly. Why does magnetic charge change div B = 0 for magnetic
fields of charges in motion?
[quote:72bd68a549]The original premise is div B = 0, and this would no longer be valid.
[/quote:72bd68a549]
No, it would still be valid. |
|
|
| Back to top |
|
|
|
| John Schoenfeld |
| Posted: Fri Jun 04, 2004 9:50 am |
|
|
|
Guest
|
Richard Herring <junk@[127.0.0.1]> wrote in message news:<5sxmXUCc5DwAFwuq@baesystems.com>...
[quote:8a2b11882f]In message <a98beaaa.0406031501.6f8f9de9@posting.google.com>, John
Schoenfeld <j.schoenfeld@programmer.net> writes
Richard Herring <junk@[127.0.0.1]> wrote in message
news:<po3i2pa7mxvAFwUB@baesystems.com>...
In message <a98beaaa.0406021802.20b74de4@posting.google.com>, John
Schoenfeld <j.schoenfeld@programmer.net> writes
"Robert J. Kolker" <robert_kolker@hotmail.com> wrote in message
news:<aSrvc.37813$eY2.10359@attbi_s02>...
John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
It will have to do. The only magenetic fields that have been seen are
solenoidal and at right angles to the current. If someone does come up
with a magnetic monople Maxwells's Equations will have to be altered.
I don't see why they would require alteration since the equations are
considering only the special case of steady currents
Really? Which part of Maxwell's equations implies steady current?
I meant charges in motion, forgetting the reserved words steady current.
Sense no makes that.
[/quote:8a2b11882f]
Having trouble reading again? |
|
|
| Back to top |
|
|
|
| John Schoenfeld |
| Posted: Fri Jun 04, 2004 11:10 am |
|
|
|
Guest
|
"Franz Heymann" <notfranz.heymann@btopenworld.com> wrote in message news:<c9o947$2u8$1@hercules.btinternet.com>...
[quote:7d442fa582]"John Schoenfeld" <j.schoenfeld@programmer.net> wrote in message
news:a98beaaa.0406021802.20b74de4@posting.google.com...
"Robert J. Kolker" <robert_kolker@hotmail.com> wrote in message
news:<aSrvc.37813$eY2.10359@attbi_s02>...
John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence
in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not
good
enough)?
It will have to do. The only magenetic fields that have been seen
are
solenoidal and at right angles to the current. If someone does
come up
with a magnetic monople Maxwells's Equations will have to be
altered.
I don't see why they would require alteration
The equations would have to be changed so as to become symmetrical in
E<->H and D<->B
[/quote:7d442fa582]
If I observe a divergent B, why does that change the fact that
electric charges in motion induce a solenoidal B?
[quote:7d442fa582]since the equations are
considering only the special case of steady currents
That is wrong
[/quote:7d442fa582]
Yes, the wording was wrong. I meant electric charges in motion.
[quote:7d442fa582][snip]
Franz[/quote:7d442fa582] |
|
|
| Back to top |
|
|
|
| greywolf42 |
| Posted: Fri Jun 04, 2004 11:15 am |
|
|
|
Guest
|
Timo Nieminen <timo@physics.uq.edu.au> wrote in message
news:Pine.LNX.4.50.0406040900490.17435-100000@localhost...
[quote:0451d4d94a]On Thu, 3 Jun 2004, greywolf42 wrote:
Gregory L. Hansen <glhansen@steel.ucs.indiana.edu> wrote:
John Schoenfeld <j.schoenfeld@programmer.net> wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
There's no theoretical reason to prohibit magnetic monopoles. It's an
experimental matter.
An utter falsehood. Maxwell's derivation of Maxwell's equations (On
Physical Lines of Force, 1861) explicitly prohibits magnetic monopoles.
Find a magnetic monopole, and disprove Maxwell's aether!
Maxwell's ether is already disproved,
[/quote:0451d4d94a]
Really? When did Maxwell's equations get disproved?
[quote:0451d4d94a]by the experimental observation of
symmetry under Lorentz transformations.
[/quote:0451d4d94a]
Symmetry is not an observable. And 'symmetry under lorentz transformations'
is a mathematical statement.
Could you be more specific, here, about experimental observation?
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail} |
|
|
| Back to top |
|
|
|
| greywolf42 |
| Posted: Fri Jun 04, 2004 11:23 am |
|
|
|
Guest
|
Timo Nieminen <timo@physics.uq.edu.au> wrote in message
news:Pine.LNX.4.50.0406040839050.17435-100000@localhost...
[quote:89b03f65ed]On Thu, 3 Jun 2004, greywolf42 wrote:
Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 2 Jun 2004, John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields?
No. See, for example, Jackson, Classical electrodynamics, 3rd ed,
section
6.11.
Sorry, Maxwell is definitely classical. And his original definition of
"Maxwell's equations" prohibited divergence in magnetic fields. (On
Physical Lines of Force, 1861)
So what? Sure, Maxwell is definitely classical, and it may well be that
Maxwell's ether model prohibits divergence in magnetic fields. However,
Maxwell's ether model is not classical EM theory.
[/quote:89b03f65ed]
ROTFLMAO!!!!
[quote:89b03f65ed]Have you not stated in the past that in Maxwell's theory, the Maxwell
equations are only approximations valid in the case of low speed relative
to the ether of both observer and source?
[/quote:89b03f65ed]
I have indeed so stated.
[quote:89b03f65ed]What bearing, then, does
Maxwell's model have on classical EM theory?
[/quote:89b03f65ed]
Well, Maxwell's equations were derived from Maxwell's classical model. That
makes them classical.
[quote:89b03f65ed]Note well that Lorenz obtained the Maxwell equations almost simultaneously
without recourse to an ether or a mechanical model,
[/quote:89b03f65ed]
Well, this is news to me. Do you have a reference for this work of Lorenz?
[quote:89b03f65ed]and Hertz did the same later.
And then there are the modern derivations.
[/quote:89b03f65ed]
But none of these are physical derivations. They are merely mathematical
manipulations.
Irrelevant to the fact that the only physical derivation of Maxwell's
equations prohibits magnetic monopoles.
[quote:89b03f65ed]div B = 0 is simply an experimental observation.
[/quote:89b03f65ed]
That would imply that there are *no* theoretical explanations. And
Maxwell's derivation is clearly theoretical. That Lorenz, Hertz, and modern
'derivations' do not have this same theoretical limitation does not mean
that there are *no* theoretical derivations.
[quote:89b03f65ed]Of course, the theory
would need to be modified if a counter-observation is made,
[/quote:89b03f65ed]
I believe that would crisp Maxwell's theory completely. I'm not sure how
one could salvage it.
[quote:89b03f65ed]but that's not
the same as a theory prohibiting something.
[/quote:89b03f65ed]
I disagree.
[quote:89b03f65ed]div B = 0 is an experimental observation.
Yes, despite decades of looking, there are no magnetic monopoles.
Better to say that, despite decades of looking, no magnetic monopoles have
been found.
[/quote:89b03f65ed]
Your statement is more scientifically correct. (Absence of evidence is not
evidence of absence.)
However, the point I was making was that -- if they exist -- magnetic
monopoles *should* have been detected in all that searching. The
theoretical probability of their existence approaches nil.
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail} |
|
|
| Back to top |
|
|
|
| greywolf42 |
| Posted: Fri Jun 04, 2004 11:32 am |
|
|
|
Guest
|
Timo Nieminen <timo@physics.uq.edu.au> wrote in message
news:Pine.LNX.4.50.0406040855080.17435-100000@localhost...
[quote:ba204cac5a]On Thu, 3 Jun 2004, greywolf42 wrote:
Timo Nieminen <timo@physics.uq.edu.au> wrote:
It's simply the non-observation of magnetic charge. First noted,
AFAIK, by Gilbert back in around 1600.
It's also a conclusion from Maxwell's physical derivation. It's not
'just' an observation.
[cut]
These people do so because there is no fundamental reason why they
should not exist according to classical EM theory.
A false statement. You can't get more classical than Maxwell. And
Maxwell when explicitly derived his equations (On Physical Lines
of Force, 1861), the derivation found that magnetic monopoles
were theoretically impossible. Which is why they don't show up
in the equations.
Addressed in detail elsewhere in the thread.
[/quote:ba204cac5a]
Apparently you mean to do this later. Or my newsreader is acting up
again.....
[quote:ba204cac5a]To summarise:
Maxwell's ether model is not classical EM theory, as the term "classical
EM theory" is used today.
[/quote:ba204cac5a]
Ahhh, so!! The 'exclusion by definition' trick. This is as useful a
statement as:
A poodle is not a dog, as the term 'dog' is used today.
[quote:ba204cac5a][MOVED]
Do note that people have looked for, and do look for, magnetic
monopoles.
They just have never found any. :)
And while absence of evidence is not evidence of absence, they *should*
have been found if they exist. (The probability of existence if
vanishingly small.)
Well, I don't think that magnetic monopoles exist. But then, the universe
is what the universe is, and can surprise us.
[/quote:ba204cac5a]
I like surprises. I just don't care for callous disregard for history, or
attempts to shade the truth within a supposedly scientific discourse.
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail} |
|
|
| Back to top |
|
|
|
| greywolf42 |
| Posted: Fri Jun 04, 2004 1:33 pm |
|
|
|
Guest
|
Gregory L. Hansen <glhansen@steel.ucs.indiana.edu> wrote in message
news:c9o459$t1b$1@hood.uits.indiana.edu...
[quote:5fde87ab50]In article <10buv5u3gruce1d@corp.supernews.com>,
greywolf42 <mingstb@marssim-ss.com> wrote:
Gregory L. Hansen <glhansen@steel.ucs.indiana.edu> wrote in message
news:c9ncjm$k7l$4@hood.uits.indiana.edu...
In article <a98beaaa.0406021336.196c4a30@posting.google.com>,
John Schoenfeld <j.schoenfeld@programmer.net> wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
There's no theoretical reason to prohibit magnetic monopoles. It's an
experimental matter.
An utter falsehood. Maxwell's derivation of Maxwell's equations (On
Physical Lines of Force, 1861) explicitly prohibits magnetic monopoles.
Find a magnetic monopole, and disprove Maxwell's aether!
Maxwell's equations can easily be symmetrized to include electrical and
magnetic charge,
[/quote:5fde87ab50]
This is quite true, mathematically.
[quote:5fde87ab50]and nobody cares what quaint pictures of swirling fluids
Maxwell might have had in mind at the time.
[/quote:5fde87ab50]
If no one cared, then you could freely have admitted that magnetic monopoles
violated Maxwell's derivation of Maxwell's equations. Instead you posted
the lie that there was no theoretical reason against magnetic monopoles.
--
greywolf42
ubi dubium ibi libertas
{remove planet for return e-mail} |
|
|
| Back to top |
|
|
|
| Timo Nieminen |
| Posted: Sun Jun 06, 2004 4:53 pm |
|
|
|
Guest
|
On Fri, 4 Jun 2004, greywolf42 wrote:
[quote:d9f5a15485]Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 3 Jun 2004, greywolf42 wrote:
Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 2 Jun 2004, John Schoenfeld wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields?
No. See, for example, Jackson, Classical electrodynamics, 3rd ed,
section
6.11.
Sorry, Maxwell is definitely classical. And his original definition of
"Maxwell's equations" prohibited divergence in magnetic fields. (On
Physical Lines of Force, 1861)
So what? Sure, Maxwell is definitely classical, and it may well be that
Maxwell's ether model prohibits divergence in magnetic fields. However,
Maxwell's ether model is not classical EM theory.
ROTFLMAO!!!!
Have you not stated in the past that in Maxwell's theory, the Maxwell
equations are only approximations valid in the case of low speed relative
to the ether of both observer and source?
I have indeed so stated.
[/quote:d9f5a15485]
Then Maxwell's ether model is not classical EM theory. Do note that
"classical electromagnetic theory" is a technical term with a meaning more
precise than "classical" "electromagnetic theory". Ritz's and Weber's
electromagnetic theories are classical as well, but they're not "classical
electromagnetic theory", either.
[quote:d9f5a15485]What bearing, then, does
Maxwell's model have on classical EM theory?
Well, Maxwell's equations were derived from Maxwell's classical model. That
makes them classical.
[/quote:d9f5a15485]
No, that isn't what makes them classical.
[quote:d9f5a15485]Note well that Lorenz obtained the Maxwell equations almost simultaneously
without recourse to an ether or a mechanical model,
Well, this is news to me. Do you have a reference for this work of Lorenz?
[/quote:d9f5a15485]
Given that the paper by Jackson & Okun (RMP 2001) you have been previously
referred to, and the content of which you did discuss over the course of
many posts in a previous thread, discusses the work of Lorenz, and gives
references to Lorenz's original publication, I am somewhat surprised that
this is news to you.
Jackson & Okun also note that Maxwell refers to Lorenz's work in his
Treatise.
[quote:d9f5a15485]and Hertz did the same later.
And then there are the modern derivations.
But none of these are physical derivations. They are merely mathematical
manipulations.
[/quote:d9f5a15485]
Why? Both Lorenz and Hertz made use of the physical behaviour of
electromagnetic systems in their derivations. How they merely mathematical
manipulations?
The modern derivations are very firmly based on a small set of
well-observed physical phenomena.
All more physical than Maxwell's model, in that they don't invoke the
mechanical properties of a non-existent ether.
[quote:d9f5a15485]Irrelevant to the fact that the only physical derivation of Maxwell's
equations prohibits magnetic monopoles.
[/quote:d9f5a15485]
But, as you have repeatedly said, the Maxwell equations are only an
approximation of the behaviour of Maxwell's mechanical model.
Is div B = 0 an approximation, or is it actually exact? If it is exact, in
what way are the Maxwell equations an approximation?
[quote:d9f5a15485]div B = 0 is simply an experimental observation.
That would imply that there are *no* theoretical explanations. And
Maxwell's derivation is clearly theoretical. That Lorenz, Hertz, and modern
'derivations' do not have this same theoretical limitation does not mean
that there are *no* theoretical derivations.
Of course, the theory
would need to be modified if a counter-observation is made,
I believe that would crisp Maxwell's theory completely. I'm not sure how
one could salvage it.
[/quote:d9f5a15485]
Maybe it would crisp Maxwell's model completely. But so what? Maxwell's
mechanical model is already defunct. Classical EM theory, as the term is
currently used in physics, would have no difficulty accomodating it.
[cut remainder]
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
|
|
| Back to top |
|
|
|
| Timo Nieminen |
| Posted: Sun Jun 06, 2004 5:01 pm |
|
|
|
Guest
|
On Fri, 4 Jun 2004, greywolf42 wrote:
[quote:e82134477f]Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 3 Jun 2004, greywolf42 wrote:
Gregory L. Hansen <glhansen@steel.ucs.indiana.edu> wrote:
John Schoenfeld <j.schoenfeld@programmer.net> wrote:
Is there anything in classical e&m that _prohibits_ a divergence in
magnetic fields? If so, what precisely is it that forces _all_
magnetic fields to be solenoidal (abductive reasoning is not good
enough)?
There's no theoretical reason to prohibit magnetic monopoles. It's an
experimental matter.
An utter falsehood. Maxwell's derivation of Maxwell's equations (On
Physical Lines of Force, 1861) explicitly prohibits magnetic monopoles.
Find a magnetic monopole, and disprove Maxwell's aether!
Maxwell's ether is already disproved,
Really? When did Maxwell's equations get disproved?
[/quote:e82134477f]
As you have repeatedly written, the Maxwell equations are only an
approximate description of Maxwell's ether. One can therefore disprove
Maxwell's ether without disproving the Maxwell equations. In fact, one can
disprove Maxwell's ether by failing to disprove the Maxwell equations.
[quote:e82134477f]by the experimental observation of
symmetry under Lorentz transformations.
Symmetry is not an observable.
[/quote:e82134477f]
You can look at something with mirror symmetry and see that it is
symmetric about its plane of symmetry?
[quote:e82134477f]And 'symmetry under lorentz transformations'
is a mathematical statement.
[/quote:e82134477f]
.... with a physical meaning.
Mathematical fact: the Maxwell equations are Lorentz symmetric.
Physical fact: the Maxwell equations describe classical EM for all
observed velocities of sources, for inertial reference frames.
[quote:e82134477f]Could you be more specific, here, about experimental observation?
[/quote:e82134477f]
Wolf et al, PRL 90, 060402 (2003) for starters. But there are plenty more.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
|
|
| Back to top |
|
|
|
| Timo Nieminen |
| Posted: Sun Jun 06, 2004 5:15 pm |
|
|
|
Guest
|
On Fri, 4 Jun 2004, greywolf42 wrote:
[quote:ef6b0670e0]Timo Nieminen <timo@physics.uq.edu.au> wrote:
On Thu, 3 Jun 2004, greywolf42 wrote:
Timo Nieminen <timo@physics.uq.edu.au> wrote:
It's simply the non-observation of magnetic charge. First noted,
AFAIK, by Gilbert back in around 1600.
It's also a conclusion from Maxwell's physical derivation. It's not
'just' an observation.
[cut]
These people do so because there is no fundamental reason why they
should not exist according to classical EM theory.
A false statement. You can't get more classical than Maxwell. And
Maxwell when explicitly derived his equations (On Physical Lines
of Force, 1861), the derivation found that magnetic monopoles
were theoretically impossible. Which is why they don't show up
in the equations.
Addressed in detail elsewhere in the thread.
Apparently you mean to do this later. Or my newsreader is acting up
again.....
[/quote:ef6b0670e0]
Odd. Your reply to the post where this was addressed in more detail shows
up as posted earlier than this one on both my local newsserver and google.
[quote:ef6b0670e0]To summarise:
Maxwell's ether model is not classical EM theory, as the term "classical
EM theory" is used today.
Ahhh, so!! The 'exclusion by definition' trick. This is as useful a
statement as:
A poodle is not a dog, as the term 'dog' is used today.
[/quote:ef6b0670e0]
Are you wanting to discuss physics, or are you just trolling? First, you
introduce a misleading and irrelevant point into an already existing
discussion, and then you start with cheap debating tricks like the one
above.
Do note that the statement:
[quote:ef6b0670e0]Maxwell's ether model is not classical EM theory, as the term "classical
EM theory" is used today.
is actually true. If you doubt this, try reading some classical EM theory[/quote:ef6b0670e0]
textbooks.
Your statement that the above statement is as useful as:
[quote:ef6b0670e0]A poodle is not a dog, as the term 'dog' is used today.
which is (1) off-topic and (2) wrong is simply incorrect, since the former[/quote:ef6b0670e0]
is (1) relevant to your intended diversion into an irrelevant discussion
of Maxwell's ether model, and (2) correct.
So away with your cheap debating tricks!
Do note that I did not invent any new definitions above, just reminded you
of the industry standard definition that is in common use. Your claim to
be a victim of "exclusion by definition" is rather flimsy.
[quote:ef6b0670e0]Do note that people have looked for, and do look for, magnetic
monopoles.
They just have never found any. :)
And while absence of evidence is not evidence of absence, they *should*
have been found if they exist. (The probability of existence if
vanishingly small.)
Well, I don't think that magnetic monopoles exist. But then, the universe
is what the universe is, and can surprise us.
I like surprises. I just don't care for callous disregard for history, or
attempts to shade the truth within a supposedly scientific discourse.
[/quote:ef6b0670e0]
Neither do I. That's why I think cheap debating tricks should be avoided.
Stick to the physics.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html |
|
|
| Back to top |
|
|
|
|
|
All times are GMT - 5 Hours
The time now is Sun Nov 08, 2009 4:40 pm
|
|