Science > Physics > Scope of classical physics -- includes relativity or not?
| Topic: |
Science > Physics |
| User: |
"Western Larch" |
| Date: |
18 Feb 2004 09:32:10 AM |
| Object: |
Scope of classical physics -- includes relativity or not? |
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Newtonian mechanics -- definitely classical, right?
Wave/particle duality -- ??
Photoelectric effect -- ??
Special relativity -- ??
General relativity -- ??
Quantum mechanics -- definitely nonclassical, right?
I've seen a definition of classical as "everything before the
introduction of quantum mechanics". Can someone propose a better one?
Thanks for your comments!
LO
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| User: "Mark Martin" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 01:27:13 PM |
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(Western Larch) wrote in message news:<6869c57c.0402180732.45dca4ae@posting.google.com>...
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Newtonian mechanics -- definitely classical, right?
Wave/particle duality -- ??
Photoelectric effect -- ??
Special relativity -- ??
General relativity -- ??
Quantum mechanics -- definitely nonclassical, right?
I've seen a definition of classical as "everything before the
introduction of quantum mechanics". Can someone propose a better one?
Thanks for your comments!
LO
Nowadays "classical" means physics at certain extremes. For
instance, Einsteinian theory reduces to Newtonian theory at the low
velocity limit. As velocity approaches zero, Einsteinian stipulations
become increasingly negligible. Similarly, the subtleties of quantum
mechanics become negligible as the mass of a system in question grows,
and approaches Newtonian as the mass approaches infinity.
Another interesting rule of thumb: classical physics is anything
that's close enough for engineers to make trains, planes &
automobiles.
-Mark Martin
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| User: "Igor" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 01:07:21 PM |
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(Western Larch) wrote in message news:<6869c57c.0402180732.45dca4ae@posting.google.com>...
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Newtonian mechanics -- definitely classical, right?
Wave/particle duality -- ??
Photoelectric effect -- ??
Special relativity -- ??
General relativity -- ??
Quantum mechanics -- definitely nonclassical, right?
I've seen a definition of classical as "everything before the
introduction of quantum mechanics". Can someone propose a better one?
Thanks for your comments!
LO
The distinction is usually made between "classical" and "modern"
physics. There tends to be a fairly arbitrary demarcation between
them, but many agree that "modern" is everything after about 1900,
basically starting with Max Planck and his resolution of the problems
involving the Wein radiation displacement law. Hence, "modern"
incorporates both relativity and quantum theory.
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| User: "Alfred Einstead" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 12:51:45 PM |
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(Western Larch) wrote:
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
There's "classical" in the sense of pre-quantum. That includes both
Relativity and Newtonian Physics. There's classical in the sense of
non-Relativistic (and pre-quantum), which includes Newtonian Physics.
In the 21st century, as time goes on, there will be classical in
the sense of Relativity and Quantum Physics.
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| User: "Jeff Relf" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
19 Feb 2004 03:38:07 AM |
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Hi Western Larch, You asked,
" between classical and non-classical physics " ,
....
" where is the line drawn ? " .
Where is the line drawn between an atom's
wave-like properties and it's particle-like properties ?
It's not a line,
there are just degrees of particleness ...
and degrees of classicalness.
The Heisenberg Uncertainty principle
tells us that the more we know about
the mass-energy ( i.e. momentum, speed ) of a molecule
( e.g. Carbon-70 ) at the time it passes through
one of a special pair of slits
the less we know about the probability of
that molecule's position on the screen.
http://www.phys.virginia.edu/CLASSES/252/uncertainty_principle.html
When passing very large molecules through
the double-slit experiment,
how classical it is ( i.e. how particle-like it is )
depends on the temperature of the molecules.
The hotter a molecule is the more classical it becomes,
Because the more heat it radiates
the more one could theoretically know about
its mass-energy ( speed ) when it was at the slit.
From http://physicsweb.org/article/news/8/2/9
Re: The radiation from the hotter molecules,
the article said,
" Since these photons could, in principle,
be detected to reveal which slit
the molecule has passed through,
the wave-like quantum behaviour
of the molecules disappears " .
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| User: "Gregory L. Hansen" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 09:56:45 AM |
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In article <6869c57c.0402180732.45dca4ae@posting.google.com>,
Western Larch <larix_occidentalis@yahoo.com> wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Newtonian mechanics -- definitely classical, right?
Wave/particle duality -- ??
Photoelectric effect -- ??
Special relativity -- ??
General relativity -- ??
Quantum mechanics -- definitely nonclassical, right?
I've seen a definition of classical as "everything before the
introduction of quantum mechanics". Can someone propose a better one?
Thanks for your comments!
LO
Sometimes it seems classical just means non-quantum, and sometimes both
non-quantum and non-Einsteinian. And there's also semi-classical. For
instance, doing quantum mechanics but with a non-quantized (classical)
potential. Or doing collision calculations in special relativity that
involve photons, which are quantums of the electromagnetic field but for
many purposes can be considered a classical particle with no mass.
--
"What are the possibilities of small but movable machines? They may or
may not be useful, but they surely would be fun to make."
-- Richard P. Feynman, 1959
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| User: "Creative Music Synth [220]" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 02:29:52 PM |
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I am the best MIDI output
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| User: "Eric Baird" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
23 Feb 2004 07:40:02 PM |
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On 18 Feb 2004 07:32:10 -0800, (Western
Larch) wrote:
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
I think it depends on context.
In Natural Philosophy, the "classical philosophers" are guys like
Aristotle, and the "modern" guys are Copernicus and Galileio and
Newton.
If someone is talking about QM, then "classical theory" probably
means just about anything non-quantum, so the boundary is maybe around
the beginning of the C20th. To someone working on Hawking radiation,
GR makes the "classical" physics predictions about black holes and QM
makes the "modern" predictions, so the key transition is maybe the
early 1970's.
To someone writng on SR, "classical" physics usually means something
pre-SR, although exactly what is not always clear. The predictions
that SR people present as "classical physics" often seem to be the
relationships associated with a flat absolute aether stationary in the
observer's own frame.
And now we also have "classical Hawking radiation", which is the
corresponding archaic "fluid dynamics" or "acoustics" analogue of the
famous QM black hole radiation effect, and manages to be "classical"
(because it is pre-SR AND and pre-QM), but also corresponds to an
effect that first came to prominence as a post-GR "non-classical" QM
effect. So you have an effect that gets discredited in the early
C19th, destroyed completely in the early C20th, and then pops up again
in the late C20th!
Try to fit THAT into some sort of orderly historical scheme!
Or you have the wave/particle thing.
Newton said that you could describe light as a wave or as a particle
and get the same answers. Then the subject split geographically into
the "waveists" on the European continent and the "particleists" in
England, and then the "waveists" won and proved emphatically that
particle theory was wrong, and then we got QM and photons, and then we
got back to wave/particle duality again!
So what in that hodgepoge woudl count as the "classical" view of
light? :)
Or relativity. To Galileao and Newton there probably wouldn't have
been any reason to suppose that light was /not/ subject to the
principle of relativity like the rest of Newtonian mechanics, and with
emission theory, light /was/ relativistic.
But then the "wave" guys won and discredited particle theory, and
since we didn't have a solid relativitic aether theory, probably
reckoned that the idea of light obeying the principle of relativity
was an old fashioned thing old held onto by "old" physicists whose
minds weren't flexible enough to embrace the new way that physics
"really" worked. And then we rediscovered the idea of relativistic
light again! :)
Thing is, physics people like to take messy data and reorganise it to
into a nice logical scheme, filtered and data-reduced to reveal the
underlying forces and themes, and history often isn't like that ...
when you look at a real historical mess (of the sort that often arises
with physics history!), and try to distil out the underlying pattern
.... sometimes the underlying structure and the background forces that
you wan tt isolate, pointing progress steadily in a particular
direction, just aren't in there.
It's a chaotic human enterprise, and as such consists partly of a
catalogue of cockups and fluke results and chance encounters and
mistakes that somehow came right and correct predictions that somehow
got discredited or forgotten.
So, in terms of chaos theory, I guess that physics history is itself
probably non-classical!
:)
=Erk= (Eric Baird)
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| User: "Timo Nieminen" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
19 Feb 2004 03:24:14 AM |
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On Wed, 18 Feb 2004, Western Larch wrote:
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Newtonian mechanics -- definitely classical, right?
Sure.
Special relativity -- ??
General relativity -- ??
Depends.
And to put the rest together:
Wave/particle duality -- ??
Photoelectric effect -- ??
Quantum mechanics -- definitely nonclassical, right?
Sure.
I've seen a definition of classical as "everything before the
introduction of quantum mechanics". Can someone propose a better one?
Better to say either:
classical = non-quantum
or
classical = non-quantum, non-relativistic
Both meanings are in common use. Note that a lot of work in classical
physics has been done after the introduction of quantum mechanics, so a
chronological definition is inadequate.
The two meanings are both in use since classical mechanics is
non-relativistic, and classical electrodynamics is relativistic.
One should also note that terms like "classical mechanics" does not mean
simply a classical theory of mechanics, but refers to a specific theory
(which is classical). For example, Aristotlean mechanics is classical, but
it isn't "classical mechanics". Same for classical electromagnetic theory
and Weber's EM theory.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
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| User: "Uncle Al" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 12:29:50 PM |
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Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity and h=zero.
When either or both of these are no longer good approximations you are
in a non-classical ansatz.
Galilean transforms - classical.
Lorentzian transforms - non-classical.
Continuous properties - classical
Quantized properties - non-classical
Deterministic quantities - classical
Heisenberg Uncertainty - non-classical
[snip]
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
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| User: "John Kennaugh" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
20 Feb 2004 03:36:31 PM |
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In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity
It never did anything of the kind.
1267 Roger Bacon suggested the speed of light was finite and was
propagated waves.
1676 Romer got a value of 2x10^8 by studying the moons of Jupiter
1727 Bradley got a value of 3.01x10^8 by studying aberration.
I would suggest that the classical period ended when physics decided
that it could accept answers which did not comply with common sense.
e.g. relativity, the wave particle duality.
I would suggest that non-classical physics has now been superseded by
modern - physics the break point being when it was decided that maths
are more real than physical processes and that it is no longer necessary
to consider questions relating to physical processes.
It is rather difficult to see where modern-physics ends and loony
physics or the competitive sport of hyper Mathematics begins. e.g.
searching for the holy grail of unification using string theory and
endowing the universe with 10 or 26 dimensions in the hope that the
infinities will cancel.
--
John Kennaugh
to email take 'yourfinger' out
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| User: "Pmb" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
20 Feb 2004 03:54:02 PM |
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"John Kennaugh" <john@kennaugh.yourfingerdemon.co.uk> wrote in message
news:Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk...
In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity
Actually that has never been the case after Maxwell and when it was shown
that light is an EM wave. It was known before relativity that the speed of
light was finite. In fact it was even know what the speed of light was.
Pmb
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| User: "Gregory L. Hansen" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
21 Feb 2004 07:11:38 AM |
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In article <_lvZb.37335$M8.19333@nwrdny02.gnilink.net>,
Pmb <peter.brown46NOSPAM@verizon.net> wrote:
"John Kennaugh" <john@kennaugh.yourfingerdemon.co.uk> wrote in message
news:Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk...
In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity
Actually that has never been the case after Maxwell and when it was shown
that light is an EM wave. It was known before relativity that the speed of
light was finite. In fact it was even know what the speed of light was.
He said c=infinity, not that the speed of light equals infinity.
--
"And don't skimp on the mayonnaise!"
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| User: "Gauge" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
21 Feb 2004 03:48:18 PM |
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(Gregory L. Hansen) wrote
He said c=infinity, not that the speed of light equals infinity.
Please explain the difference.
Pmb
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| User: "Gregory L. Hansen" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
21 Feb 2004 08:28:42 PM |
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In article <e7203033.0402211348.30522314@posting.google.com>,
Gauge <gauge5@hotmail.com> wrote:
glhansen@steel.ucs.indiana.edu (Gregory L. Hansen) wrote
He said c=infinity, not that the speed of light equals infinity.
Please explain the difference.
Pmb
c is the invariant speed. It appears in the transformations between
reference frames, the magnitude of momentum versus speed, and so on. The
speed of light is the speed that light travels in a vacuum. They happen
to be the same because light travels just as fast as it can travel, and c
is identified as the speed of light more as an historical accident. It
could as well be called the speed of gluons. In Maxwell's aether theory,
the speed of light isn't determined by the invariant speed, but rather by
the properties of the aether, and Maxwell's theory follows Galilean
transformations. So there would be no contradiction at all if we let c
go to infinity while the speed of light remains finite.
--
"For every problem there is a solution which is simple, clean and wrong."
-- Henry Louis Mencken
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| User: "FrediFizzx" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
21 Feb 2004 09:27:44 PM |
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"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote in message
news:c1944q$cmf$2@hood.uits.indiana.edu...
| In article <e7203033.0402211348.30522314@posting.google.com>,
| Gauge <gauge5@hotmail.com> wrote:
| >glhansen@steel.ucs.indiana.edu (Gregory L. Hansen) wrote
| >
| >> He said c=infinity, not that the speed of light equals infinity.
| >
| >Please explain the difference.
| >
| >Pmb
|
|
| c is the invariant speed. It appears in the transformations between
| reference frames, the magnitude of momentum versus speed, and so on. The
| speed of light is the speed that light travels in a vacuum. They happen
| to be the same because light travels just as fast as it can travel, and c
| is identified as the speed of light more as an historical accident. It
| could as well be called the speed of gluons. In Maxwell's aether theory,
| the speed of light isn't determined by the invariant speed, but rather by
| the properties of the aether, and Maxwell's theory follows Galilean
| transformations. So there would be no contradiction at all if we let c
| go to infinity while the speed of light remains finite.
Hmmm? I was under the impression that Maxwell's theory doesn't follow
Galilean transformations. And that was the reason Einstein formulated SR to
start with.
FrediFizzx
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| User: "Gregory L. Hansen" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
22 Feb 2004 07:11:15 AM |
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In article <c197ja$1fe0vn$1@ID-185976.news.uni-berlin.de>,
FrediFizzx <fredifizzx@hotmail.com> wrote:
"Gregory L. Hansen" <glhansen@steel.ucs.indiana.edu> wrote in message
news:c1944q$cmf$2@hood.uits.indiana.edu...
| In article <e7203033.0402211348.30522314@posting.google.com>,
| Gauge <gauge5@hotmail.com> wrote:
| >glhansen@steel.ucs.indiana.edu (Gregory L. Hansen) wrote
| >
| >> He said c=infinity, not that the speed of light equals infinity.
| >
| >Please explain the difference.
| >
| >Pmb
|
|
| c is the invariant speed. It appears in the transformations between
| reference frames, the magnitude of momentum versus speed, and so on. The
| speed of light is the speed that light travels in a vacuum. They happen
| to be the same because light travels just as fast as it can travel, and c
| is identified as the speed of light more as an historical accident. It
| could as well be called the speed of gluons. In Maxwell's aether theory,
| the speed of light isn't determined by the invariant speed, but rather by
| the properties of the aether, and Maxwell's theory follows Galilean
| transformations. So there would be no contradiction at all if we let c
| go to infinity while the speed of light remains finite.
Hmmm? I was under the impression that Maxwell's theory doesn't follow
Galilean transformations. And that was the reason Einstein formulated SR to
start with.
Maxwell's theory follows from experimental results, actually. Plus the
addition of a displacement current. At the time, Galilean transformations
were just an assumed postulate; I'm not sure it even occured to anyone
that the transformation rules could by anything else. Maxwell's equations
aren't invariant under Galilean transformations, but that was not thought
to be a problem because of the preferred frame defined by the aether, just
as air defines a preferred frame for sound waves. Later experimental
results showed the problem.
Maxwell's equations can be deduced by Coulomb's law and the special theory
of relativity. That's considered a great accomplishment because it shows
why Maxwell's equations must have the form they do, unifies the electric
and magnetic forces, and makes radiation a necessary aspect of
conservation of energy. But if you ignore experimental details, I don't
think there was anything logically inconsistent with Maxwell's Galilean
electromagnetism.
--
"Things should be made as simple as possible -- but no simpler."
-- Albert Einstein
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| User: "Gauge" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
22 Feb 2004 06:56:48 AM |
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(Gregory L. Hansen) wrote in message news:<c1944q$cmf$2@hood.uits.indiana.edu>...
In article <e7203033.0402211348.30522314@posting.google.com>,
Gauge <gauge5@hotmail.com> wrote:
(Gregory L. Hansen) wrote
He said c=infinity, not that the speed of light equals infinity.
Please explain the difference.
Pmb
c is the invariant speed.
Ah! Okay. Thanks Greg.
Pmb
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| User: "Uncle Al" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
20 Feb 2004 06:17:51 PM |
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Pmb wrote:
"John Kennaugh" <john@kennaugh.yourfingerdemon.co.uk> wrote in message
news:Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk...
In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity
Actually that has never been the case after Maxwell and when it was shown
that light is an EM wave. It was known before relativity that the speed of
light was finite. In fact it was even know what the speed of light was.
Newton's equations aren't what was published in "Principia" if you add
terms that vanish when c=infinity.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
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| User: "Pmb" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
20 Feb 2004 06:21:00 PM |
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"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:4036A3AF.9117595B@hate.spam.net...
Pmb wrote:
"John Kennaugh" <john@kennaugh.yourfingerdemon.co.uk> wrote in message
news:Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk...
In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat
arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity
Actually that has never been the case after Maxwell and when it was
shown
that light is an EM wave. It was known before relativity that the speed
of
light was finite. In fact it was even know what the speed of light was.
Newton's equations aren't what was published in "Principia" if you add
terms that vanish when c=infinity.
What Newtonian equations do you claim contain "c" ?
.
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| User: "Uncle Al" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
20 Feb 2004 08:19:15 PM |
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Pmb wrote:
"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:4036A3AF.9117595B@hate.spam.net...
Pmb wrote:
"John Kennaugh" <john@kennaugh.yourfingerdemon.co.uk> wrote in message
news:Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk...
In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat
arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity
Actually that has never been the case after Maxwell and when it was
shown
that light is an EM wave. It was known before relativity that the speed
of
light was finite. In fact it was even know what the speed of light was.
Newton's equations aren't what was published in "Principia" if you add
terms that vanish when c=infinity.
What Newtonian equations do you claim contain "c" ?
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
A more accurate sum vs. observation is (V1 + V2)/[1 +(V1)(V2)/c^2].
Newton tacitly assumes lightpeed is infinite and Planck's constant is
zero. Ernest O. Lawrence found out that wasn't true. When he got
good at building cyclotrons he had to go to synchrotrons. Nature's
little jest.
Einstein assumed the Equvalence Principle, that all bodies fall
indentically in vacuum, that inertial and gravitational mass is
fundamentally indistinguishable. Any and all good theories of
gravitation have to predict the observed universe. Nature's little
jest is that the only slack in the gears is the Equivalence Principle
- it's not necessary to a theory of gravitation. The EP is
convenient.
If test mass parity violates the EP, it sneaks beneath notice. There
are no parity-segregated astronomic bodies. If test mass parity
violates the EP, we have a natural and all-pervasive reason why
biology is homochiral planetwide: Left-handed life has a different
free energy than right-handed life right at the starting line. It
would be true for the whole universe, too - including trace abiotic
amino acids in meteorites. All meteoric amino acids should be
enriched in the l-isomer (except glycine, of course). Is tehr a
footenote and some fine print?
Eric Adelberger and/or Riley Newman should look and see if calculated
extremal opposite parity test masses of identical chemical composition
fall differently in vacuum,
http://www.mazepath.com/uncleal/qz.pdf
It's an entirely straightforward experiment in existing apparatus run
according to established protocols by its academic keepers using
commercially available inexpensive left- vs. right-handed alpha-quartz
test masses. No EP test has given an non-null result within
experimental error since Galileo in 1590. Uncle Al guarantees that
the parity Eotvos experiment will fully meet that historical standard
of excellence, and have a 50% chance of exceeding it.
If theory has hidden terms, you don't know they are there until you
test for them. Even some of the explicit stuff is mildy sour: The
relation between the “time” t of the system, i.e. the time as reckoned
by the clock at the origin of co-ordinates of the accelerated frame,
and the “local time” tau of the system, i.e. the time as reckoned by a
clock at z in the accelerated system, was found in GR to be
tau = (1 + gz/c^2)t
But it isn't! It is approximated to be the foregoing. (g is
acceleration, z is distance scale) The more rigorous treatment is
tau = e^[(gz/c^2)]t
If you are in a starship doing lighyears, the truncated terms make a
difference. If you are a GPS satellite, they do not. One should take
care that things are kept as simple as they can be, but not so simple
that they stop working.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
"Quis custodiet ipsos custodes?" The Net!
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| User: "Pmb" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
21 Feb 2004 04:18:02 AM |
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"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:4036C023.21CBF9A6@hate.spam.net...
Pmb wrote:
"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:4036A3AF.9117595B@hate.spam.net...
Pmb wrote:
"John Kennaugh" <john@kennaugh.yourfingerdemon.co.uk> wrote in
message
news:Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk...
In message <4033AF1E.9A795905@hate.spam.net>, Uncle Al
<UncleAl0@hate.spam.net> writes
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and
nonclassical
physics. I do understand that the distinction is somewhat
arbitrary --
we can make up whatever names we like. My question is, in
common
parlance (say textbooks, articles, etc) where is the line
drawn?
Bottom line: classical physics tacitly assumes c=infinity
Actually that has never been the case after Maxwell and when it was
shown
that light is an EM wave. It was known before relativity that the
speed
of
light was finite. In fact it was even know what the speed of light
was.
Newton's equations aren't what was published in "Principia" if you add
terms that vanish when c=infinity.
What Newtonian equations do you claim contain "c" ?
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
A more accurate sum vs. observation is (V1 + V2)/[1 +(V1)(V2)/c^2].
Newton tacitly assumes lightpeed is infinite and Planck's constant is
zero.
We were speaking about classical mechanics. So you're taking that to include
Newton's assumptions?? Why? Classical mechanics does not contain anything to
do with light. If you want to address the physics of light prior to SR then
that's Maxwell's equations
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| User: "Eric Baird" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
23 Feb 2004 06:48:54 PM |
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On Fri, 20 Feb 2004 18:19:15 -0800, Uncle Al <UncleAl0@hate.spam.net>
wrote:
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
Hmm. I don't remember seeing him write that anywhere.
I remember seeing a lot of other people /saying/ that Newton said
this, but then ... those people also tend to say silly things like
"Newton thought space was flat".
Physicists don't always go back to the primary sources to check things
as often as they should.
A more accurate sum vs. observation is (V1 + V2)/[1 +(V1)(V2)/c^2].
Velocity-additional formulae apply in a variety of theories, where
they can be used to give the "equivalent" velocity associated with a
compound frequency shift.
For instance, with Newtonian emission theory, I seem to remember the
equivalent exercise giving a velocity addition formula for two
like-sign velocities acting in a line, of
: V = v1 + v2 - v1v2/c^2
I think Oliver Lodge (and others?) worked out the corresponding
velocity-addition formula for some aether models.
One of the things that we have to remember about Einstein's early
writings (and by this I mean stuff before ~1925) is that during this
whole period, Einstein did not seem to have yet gotten around to
checking up on what it was that Newton had actually written!
So in Einstein's Leyden lecture we have Einstein confidently
explaining to the audience the history of "aether" theories, and
saying that Newton "might as well have" used the word aether ...
apparently blissfully unaware that Newton used the word incessantly
throughout Optiks!
So I think that as late as the early 1920's Einstein still didn't seem
to have read for himself what it was that Newton had actually written
on the subject, which is kinda ironic considering that Einstein's own
work on light and on QM actually paralleled Newton's in a lot of ways.
Newton proposed wave-particle duality, Einstein was partly responsible
for quantum mechanics. Newton had guide waves, QM had pilot waves.
Newton proposed that light and matter were generally interchangeable,
Einstein published E=mc^2.
Optiks was considered to be discredited and was politely "buried" to
protect the dead Newton's reputation, and then finally came back into
print in [the 1930's?] after some people realised the relevance of
some of Newton's "wackier" ideas to modern QM, so perhaps Einstein
didn't get the chance to read it until then.
Newton tacitly assumes lightpeed is infinite and Planck's constant is
zero.
=Erk= (Eric Baird)
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| User: "John Kennaugh" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
22 Feb 2004 05:42:44 AM |
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Uncle Al writes
Bottom line: classical physics tacitly assumes c=infinity
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
A more accurate sum vs. observation is (V1 + V2)/[1 +(V1)(V2)/c^2].
What you actually mean is that the modern equation = Newton's version if
you make c = infinity.
What Newton would almost certainly have assumed is that the speed of
light is finite and that it adds to the speed of the source in
accordance with the principle of relativity. In other words
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
even if V2 is the speed of light and V1 that of the source. One could
argue that none classical physics was precipitated by MMX. One has a
source, an observer and the space in between. MMX had apparently
eliminated the space in between as controlling the speed of light
contrary to the belief which had existed for 200years. That leaves the
source and the observer. I don't think that anyone since Euclid ~300BC
has suggested that light is controlled by the observer, so that leaves
the source. The obvious interpretation of MMX is therefore that the
speed of light is constant w.r.t the source rather than had previously
thought, the ether, showing that Newton was right and that the speed of
light adds to that of the source just like every other speed adds. Later
of course Newton's corpuscles were found to exist and renamed photons.
Lorentz of course was totally convinced that the wave ether theory is
correct despite MMX. He explained MMX by hypothesising matter/ether
interaction to provide a fiddle factor to make the observer get the same
result independent of motion. Modern theory is based on that same fiddle
factor with no alternative theory to justify it other than the way
Lorentz did although many in this NG practice self deception in this
regard.
The suggestion that Newton got it wrong because he thought c was
infinite is about the most convoluted, distorted and arrogant way
imaginable of looking at it.
--
John Kennaugh
to email take 'yourfinger' out
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| User: "" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
22 Feb 2004 04:56:07 PM |
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In article <d+jPreF0WJOAFwbG@kennaughyourfinger.demon.co.uk>, John Kennaugh <john@kennaugh.yourfingerdemon.co.uk> writes:
Uncle Al writes
Bottom line: classical physics tacitly assumes c=infinity
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
A more accurate sum vs. observation is (V1 + V2)/[1 +(V1)(V2)/c^2].
What you actually mean is that the modern equation = Newton's version if
you make c = infinity.
What Newton would almost certainly have assumed is that the speed of
light is finite and that it adds to the speed of the source in
accordance with the principle of relativity. In other words
Sum two in-line velocities V1 and V2. Newton says the sum is V1+V2.
even if V2 is the speed of light and V1 that of the source. One could
argue that none classical physics was precipitated by MMX. One has a
source, an observer and the space in between. MMX had apparently
eliminated the space in between as controlling the speed of light
contrary to the belief which had existed for 200years. That leaves the
source and the observer. I don't think that anyone since Euclid ~300BC
has suggested that light is controlled by the observer, so that leaves
the source. The obvious interpretation of MMX is therefore that the
speed of light is constant w.r.t the source rather than had previously
thought, the ether, showing that Newton was right and that the speed of
light adds to that of the source just like every other speed adds. Later
of course Newton's corpuscles were found to exist and renamed photons.
Lorentz of course was totally convinced that the wave ether theory is
correct despite MMX. He explained MMX by hypothesising matter/ether
interaction to provide a fiddle factor to make the observer get the same
result independent of motion. Modern theory is based on that same fiddle
factor with no alternative theory to justify it other than the way
Lorentz did although many in this NG practice self deception in this
regard.
The suggestion that Newton got it wrong because he thought c was
infinite is about the most convoluted, distorted and arrogant way
imaginable of looking at it.
If by c we mean the speed of light then yes, this, suggestion is downright
*idiotic*. I would ask anybody suggesting such to show me in what way
does the speed of light has any any bearing on any of Newton's laws.
What causes the confusion is a misunderstanding of what c is. c is
not the speed of light. I'll repeat, for the benefit of all the
"coffee table book school of physics" graduates out there, ***c is not
the speed of light***. c is a maximal speed of information transfer.
It can be shown that if such speed exists, it is unique and invariant,
and conversely that if a unique and invariant speed exists, then it is
the maximal speed of information transfer.
So, it is not that c is the speed of light, rather that, to the bset
of our knowledge, light at vacuum happens to be moving at c (since we
observe the speed of said light to be invariant).
Thus, knowledge of of the fact that speed of light is finite has
absolutely no bearing on Newton's physics, no more so than the
knowledge that the speed of riflr bullets is finite. It is the
knowledge that speed of light is *invariant* that makes the
difference.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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| User: "Eric Baird" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
23 Feb 2004 05:58:41 PM |
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On Sun, 22 Feb 2004 11:42:44 +0000, John Kennaugh
<john@kennaugh.yourfingerdemon.co.uk> wrote:
The suggestion that Newton got it wrong because he thought c was
infinite is about the most convoluted, distorted and arrogant way
imaginable of looking at it.
I'm pretty sure that Newton actually quoted a value for the speed of
light in Optics or Principia (although I forget whether he gave an
absolute value or a ratio wrt the speed of sound).
My books are in storage, perhaps someone with a copy handy can give us
a quote.
Jupiter's moon system made a convenient "clockwork" system that
allowed very precise visual timings, and astronomers had noticed an
apparent variation in the exact timings of the eclipses of Jupiter's
moons and related this to the variation in the Earth-Jupiter distance
between observations ... if Jupiter was nearer, the eclipse was seen
to happen earlier than predicted, if Jupiter was further away the
moment of eclipse happened later.
From what I remember, Newton's quoted estimate for lightspeed was
actually pretty good.
=Erk= (Eric Baird)
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| User: "" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
20 Feb 2004 09:08:40 PM |
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John Kennaugh <john@kennaugh.yourfingerdemon.co.uk> wrote in message news:<Rjqc8oLf3nNAFwDa@kennaughyourfinger.demon.co.uk>...
I would suggest that the classical period ended when physics decided
that it could accept answers which did not comply with common sense.
Common sense is by definition inapplicable to situations in which
e.g. relativity, the wave particle duality
tend to be used, since such situations are far beyond common experience.
So that might not be too bad a definition.
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| User: "Eric Baird" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
23 Feb 2004 06:05:18 PM |
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On Wed, 18 Feb 2004 10:29:50 -0800, Uncle Al <UncleAl0@hate.spam.net>
wrote:
Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Bottom line: classical physics tacitly assumes c=infinity and h=zero.
When either or both of these are no longer good approximations you are
in a non-classical ansatz.
Galilean transforms - classical.
Lorentzian transforms - non-classical.
Continuous properties - classical
Quantized properties - non-classical
Deterministic quantities - classical
Heisenberg Uncertainty - non-classical
[snip]
So, since Newton described optical and gravitational effects in terms
of a variation in lightspeeds that related to a variation in the
density of the background medium, you are saying that Newton was
non-classical?
=Erk= (Eric Baird)
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| User: "EjP" |
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| Title: Re: Scope of classical physics -- includes relativity or not? |
18 Feb 2004 12:01:04 PM |
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Western Larch wrote:
Hello,
A distinction is sometimes made between classical and nonclassical
physics. I do understand that the distinction is somewhat arbitrary --
we can make up whatever names we like. My question is, in common
parlance (say textbooks, articles, etc) where is the line drawn?
Newtonian mechanics -- definitely classical, right?
Wave/particle duality -- ??
Photoelectric effect -- ??
Special relativity -- ??
General relativity -- ??
Quantum mechanics -- definitely nonclassical, right?
I've seen a definition of classical as "everything before the
introduction of quantum mechanics". Can someone propose a better one?
The term "classical physics" is not well defined in general.
Most often, it refers to "non-quantum". Sometimes, it can
refer to non-relativistic; however, in those cases
"non-relativistic" is usually a less ambigious phrase to use.
As Gregory Hansen said, there is also the complication of
"semi-classical", which can mean just about anything.
It sounds pretty confusing, but in common usage, the term
"classical" is almost always used *in conjunction* with
presenting some particular proof or derivation, so it
will become immediately apparent in context exactly
what sort of approximation the author is talking about.
-E
Thanks for your comments!
LO
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