Science > Physics > What is the "reason" C is constant to all observers?
| Topic: |
Science > Physics |
| User: |
"George Hammond" |
| Date: |
26 Aug 2005 06:43:46 PM |
| Object: |
What is the "reason" C is constant to all observers? |
Einstein's Special Relativity is famous for AD HOC
postulating that:
"All observers regardless of their relative
(uniform) velocities will measure the same
speed of light, C."
This is of course highly COUNTER INTUITIVE (the
Galilean transformation is more intuitive).
ODDLY ENOUGH, Einstein never gave a physical
reason or explanation of WHY C should be the same for
all observers regardless of their speed... he simply
AD HOC POSTULATED the fact (which has since
been experimentally confirmed a million times).
PLEASE CORRECT ME IF I AM WRONG:
But as far as I know, to this day, there is STILL NO
"logical theoretical reason"
of WHY C should appear to be the SAME to all
moving observers!
As far as I know, Quantum Theory, QED, Quantum
Field Theory, Particle Physics...... NOTHING,
offers any logical explanation for this fact... all of
them simply AD HOC ASSUME the fact just like
Einstein did in 1905.
Is that correct?
Yes, or no?
Or is there some "physical explanation" of why C
is a constant to all (uniformly) moving observers
that I don't know about?
Mystified?
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
26 Aug 2005 10:28:05 PM |
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George Hammond:
Einstein's Special Relativity is famous for AD HOC
postulating that:
"All observers regardless of their relative
(uniform) velocities will measure the same
speed of light, C."
This is of course highly COUNTER INTUITIVE (the Galilean transformation
is more intuitive).
ODDLY ENOUGH, Einstein never gave a physical reason or explanation of
WHY C should be the same for all observers regardless of their speed...
he simply AD HOC POSTULATED the fact (which has since been experimentally
confirmed a million times).
George ... I know you understand relativity well enough to know
the answer to this, so I'll assume you just need a brief refresher.
Recall that relativity is a theory of geometry, not electromagnetism,
so we can dispense with the light postulate altogether. Afterwords,
we can see under what conditions the light postulate would be correct.
Einstein's first postulate is sufficient to derive both special and
galilean relativity if we assume a four-dimensional space time with
a lorentzian manifold. Velocities are nothing more than a slope in
plane containing the t-axis. The fact that the t-axis has a different
sign than than the spatial axes, means that the lines at 45 degrees
in the (\beta = +/1) divide the spacetime into spacelike, timelike and
null intervals, with the lines at 45 degrees being null (or null cone
if you want to consider all four dimensions).
So, there's nothing special about those lines, except that historically
a line dx/dt was called a velocity while a line dy/dx had no special
designation. The use of seconds to measure the intervals along t is
convention. It could just as well be measured in meters, and in special
and general relativity, the convention c = 1, just reflects the choice
of units that is most natural.
Now that we've established that a velocity is nothing more than
the angle, `A' in a plane with a slope m = \beta = tanh(A), we
have established that observing some object moving with some
velocity is equivalent to observing a rotation of that objects
axes relative to your own.
Since the interval, ds^2 is invariant, an interval which is null
(ds^2 = 0) in one frame must be null in every frame. To add light to
this picture, we need to add some physics.
Invariance under spacetime displacements gives a conserved quantity
for each type of displacement. Traditionally, we call the invariant
under time displacements, the energy and the invariant under spatial
translations, the momentum. Together, these form a conserved current
called the four-momentum. The quantity it conserves, is by definition,
the mass. (E^2 - p^2 = m^2). Along a null ray, m = 0, so anything
with a mass of zero, _must_ lie along a null ray, and conversely,
anything which lies along a null ray must have a mass of zero. (And
since a null ray in one frame is null in every frame, the mass is zero
in every frame.) So, there is nothing special about an object which
propagates at the same velocity in every frame, other than it must
have a zero mass.
Now, we can ask where light fits into the picture. If the maxwell's
equation are correct (which makes the photon is massless), then light
propagates along null rays. Whether or not light propagates along
null rays is ultimately for experiment to decide, however, experiment
has determined that it does for at any level of precision accessible
to experiment at the moment. Also, charge conservation is tied to
light propagating along null rays. If you're looking for a _reason_
that light propagates along null rays, then charge conservation is
a reason. Why charge is conserved is not well understood, except that
it plays a role in the standard model which insures self-consistency
between the strong, weak and electromagnetic interactions.
Einstein included his second postulate only because he probably
didn't know how to make his theory more general or if that had
occured to him, he was probably being pragmatic. He really
had no reason to make it more general at the time. His motivation
was to provide a natural explanation for the form of maxwell's
equations.
PLEASE CORRECT ME IF I AM WRONG:
But as far as I know, to this day, there is STILL NO "logical
theoretical reason" of WHY C should appear to be the SAME to all
moving observers!
If it still isn't clear, ask yourself the same question about
the length of a ruler in three dimesions. Is there any logical
reason that ds^2 = dx^2 + dy^2 + dz^2 should be the same for
all observers, so that all observers measure the ruler to be
the same length, regardless of their relative orientations of
their axes? The geometry of the universe has consequences, so
for example, a 3-d euclidean geometry has coordinate transformations
that preserve ds^2, which leads to the usual pythagorean theorem:
ds^2 = dx^2 + dy^2 + dz^2 = ds'^2 = dx'^2 + dy'^2 + dz'^2.
In relativity, you have four-dimensions and a minus sign in
the metric, but otherwise the rules are the same. You get a
pythagorean theorem using exactly the same logic. The difference
is, for this geometry, you can have null intervals.
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| User: "George Hammond" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 04:04:09 AM |
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On Sat, 27 Aug 2005 03:28:05 GMT,
(Bilge) wrote:
George Hammond:
Einstein's Special Relativity is famous for AD HOC
postulating that:
"All observers regardless of their relative
(uniform) velocities will measure the same
speed of light, C."
[Hammond]
Hobba tells me this is known as the "POR" (Principle of Relativity",
if I understand him correctly.
Invariance under spacetime displacements gives a conserved quantity
for each type of displacement. Traditionally, we call the invariant
under time displacements, the energy and the invariant under spatial
translations, the momentum.
[Hammond]
right... Noether's theorem.
Together, these form a conserved current
called the four-momentum. The quantity it conserves, is by definition,
the mass. (E^2 - p^2 = m^2). Along a null ray, m = 0, so anything
with a mass of zero, _must_ lie along a null ray, and conversely,
anything which lies along a null ray must have a mass of zero. (And
since a null ray in one frame is null in every frame, the mass is zero
in every frame.) So, there is nothing special about an object which
propagates at the same velocity in every frame, other than it must
have a zero mass.
[Hammond]
So.. are you telling me that the "invarience of C" is basically
caused by the "conservation of mass"..... or rather the
"conservation of the energy current"?
i.e. that the POR is really a simple physical consequence of the
legendary "conservation of mass-energy"?
i.e. ... that unless you assume C=invarient, it is impossible
to preserve the "conservation of energy"?
..... and THAT is the physical cause of the POR?
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
03 Sep 2005 04:49:10 AM |
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George Hammond:
[Hammond]
So.. are you telling me that the "invarience of C" is basically
caused by the "conservation of mass"..... or rather the
"conservation of the energy current"?
i.e. that the POR is really a simple physical consequence of the
legendary "conservation of mass-energy"?
No, the conservation of mass-energy-momentum is a consequence of
the principle of relativity. In fact, the principle applies to
galilean relativity. The only differnce is that in appying the
principle to galilean invariance you have one additional symmetry
under which you assume the laws of physics are invariant: a galilean
boost. In addition, you have to define coordinates such that the
metric,
ds^2 = -(dx^0)^2 + (dx^1)^2 + (dx^2)^2 + (dx^3)^2
is degenerate, i.e., you still have a time direction and a
lightlike vector and can write the metric as,
ds^2 = -(dt+ dt-) + (dx^1)^2 + (dx^2)^2 + (dx^3)^2
You then get one additional conserved quantity over relativity:
the mass. That, by the way, eliminates galilean relativity as
the correct symmetry. The mass of a Hydrogen atom is less than
the mass of a proton and electron. The value of `c' has no physical
meaning.
i.e. ... that unless you assume C=invarient, it is impossible
to preserve the "conservation of energy"?
.... and THAT is the physical cause of the POR?
Again, that's backwards. If you hae some geometry, then you
automatically get conserved quantities if you expect the laws
of physics to be independent of of the coordinates. It's just
the way nature ``keeps the books,'' so-to-speak, in the simplest
way. The alternative is for nature to have some some idea of
an absolute position and time and have the laws of physics
vary from point to point. The basic idea of an ether theory
with a preferred frame is not only does nature define an absolute
frame, but nature distorts physical objects in such a way that
relativity only appears to be correct. Similarly, since there
is a preferred frame, none of these conservation laws are really
correct. They only appear to be correct. In other words, nature
somehow chose to go to a lot of effort to avoid the simplest
explanation.
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| User: "Bill Hobba" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 08:02:45 PM |
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"George Hammond" <nowhere1@nospam.net> wrote in message
news:hfa0h1h40hibupm3l5rul58rjcn105hn7m@4ax.com...
On Sat, 27 Aug 2005 03:28:05 GMT,
(Bilge) wrote:
George Hammond:
Einstein's Special Relativity is famous for AD HOC
postulating that:
"All observers regardless of their relative
(uniform) velocities will measure the same
speed of light, C."
[Hammond]
Hobba tells me this is known as the "POR" (Principle of Relativity",
if I understand him correctly.
You do not understand what I am saying - that is not the POR. The POR is
the laws of physics are the same in any inertial frame or a frame traveling
at constant velocity wrt an inertial frame.
Invariance under spacetime displacements gives a conserved quantity
for each type of displacement. Traditionally, we call the invariant
under time displacements, the energy and the invariant under spatial
translations, the momentum.
[Hammond]
right... Noether's theorem.
Together, these form a conserved current
called the four-momentum. The quantity it conserves, is by definition,
the mass. (E^2 - p^2 = m^2). Along a null ray, m = 0, so anything
with a mass of zero, _must_ lie along a null ray, and conversely,
anything which lies along a null ray must have a mass of zero. (And
since a null ray in one frame is null in every frame, the mass is zero
in every frame.) So, there is nothing special about an object which
propagates at the same velocity in every frame, other than it must
have a zero mass.
[Hammond]
So.. are you telling me that the "invarience of C" is basically
caused by the "conservation of mass"..... or rather the
"conservation of the energy current"?
No. What he is saying is that once one has developed SR and shown there is
a constant velocity then one can show that particles with zero mass travel
at that velocity. Saying that the speed of light is invariant is saying
that the photon has zero mass. The mass of the photon is an experimental
matter - and to a high degree of accuracy is found to have zero mass.
i.e. that the POR is really a simple physical consequence of the
legendary "conservation of mass-energy"?
George you still are off target. Please read the links I gave.
Thanks
Bill
i.e. ... that unless you assume C=invarient, it is impossible
to preserve the "conservation of energy"?
.... and THAT is the physical cause of the POR?
.
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| User: "George Hammond" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 01:54:49 AM |
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On Sat, 27 Aug 2005 03:28:05 GMT,
(Bilge) wrote:
George Hammond:
Einstein's Special Relativity is famous for AD HOC
postulating that:
"All observers regardless of their relative
(uniform) velocities will measure the same
speed of light, C."
This is of course highly COUNTER INTUITIVE (the Galilean transformation
is more intuitive).
ODDLY ENOUGH, Einstein never gave a physical reason or explanation of
WHY C should be the same for all observers regardless of their speed...
he simply AD HOC POSTULATED the fact (which has since been experimentally
confirmed a million times).
George ... I know you understand relativity well enough to know
the answer to this, so I'll assume you just need a brief refresher.
Recall that relativity is a theory of geometry, not electromagnetism,
so we can dispense with the light postulate altogether. Afterwords,
we can see under what conditions the light postulate would be correct.
Einstein's first postulate is sufficient to derive both special and
galilean relativity if we assume a four-dimensional space time with
a lorentzian manifold. Velocities are nothing more than a slope in
plane containing the t-axis. The fact that the t-axis has a different
sign than than the spatial axes, means that the lines at 45 degrees
in the (\beta = +/1) divide the spacetime into spacelike, timelike and
null intervals, with the lines at 45 degrees being null (or null cone
if you want to consider all four dimensions).
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
[Hammond]
Let me ask you this:
Can an answer to the question:
What is the "reason" C is constant
to all (uniformly) moving observers?
be formulated by saying:
"Because apparently uniform motion
physically causes (for some unknown
but presumably explainable reason),
a PHYSICAL CONTRACTION of rulers,
and a PHYSICAL SLOWING of clocks;
such that the speed (distance/time)
of a light ray therefore remains a
universal CONSTANT."
Would that be considered a "physical explanation"
of the constancy of the speed of light for observers
moving relativly to each other... or is that to be
considered a circular explanation?
Or... is it true that "charge conservation" is actually the
cause of the invarience of C.
Or... might it be held that "charge conservation" is a result
of assuming C is invarient?
.
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 02:49:30 AM |
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George Hammond:
On Sat, 27 Aug 2005 03:28:05 GMT,
[...]
Einstein's first postulate is sufficient to derive both special and
galilean relativity if we assume a four-dimensional space time with
a lorentzian manifold. Velocities are nothing more than a slope in
plane containing the t-axis. The fact that the t-axis has a different
sign than than the spatial axes, means that the lines at 45 degrees
in the (\beta = +/1) divide the spacetime into spacelike, timelike and
null intervals, with the lines at 45 degrees being null (or null cone
if you want to consider all four dimensions).
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
No, it isn't george. Geometry is a consequence of the universe having
_some_ geometry. What that geometry is, was up to nature. However,
one can assume different geometries, derive the consequences of those
geometries and compare each to experiment.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
I explained that in great detail. If you indicate which part wasn't
clear, perhaps I can expand on it. It appears that you are having
difficulty accepting the idea that anything but three dimensional
geometry is physical.
.
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| User: "George Hammond" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 04:29:05 AM |
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On Sat, 27 Aug 2005 07:49:30 GMT,
(Bilge) wrote:
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
I explained that in great detail. If you indicate which part wasn't
clear, perhaps I can expand on it. It appears that you are having
difficulty accepting the idea that anything but three dimensional
geometry is physical.
[Hammond]
Please avoid ad hominem remarks.
[Hammond]
The Lorentz Transformation is a DIRECT RESULT of assuming that
"C is an invarient". I.e. all you need to derive the Lorentz
Transformation is to assume C is the same to every inertial
observer.
OK... once you derive the Lorentz Transformation, the "Minkowski
rotation" gemetry is mathematically obvious. However it is all
based on the ASSUMPTION that C is what is observed by every
inertial observer, regardless of his velocity. So far no physics
except the assumption that C is invarient.
Now.... however, you point out that the Lorentz Tranformation is
NECESSARY in order to formulate a "conserved current" namely
E^2-p^2=m^2 (so called conservation of energy). Are you saying
then that the "postulate" of the invariance of C is PHYSICALLY
NECESSITATED by the requirement of the "conservation of energy".
If so, that sounds like a pretty hefty physical reason for
"postulating" that C is an invariant.
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 05:32:29 AM |
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George Hammond:
On Sat, 27 Aug 2005 07:49:30 GMT,
(Bilge) wrote:
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
I explained that in great detail. If you indicate which part wasn't
clear, perhaps I can expand on it. It appears that you are having
difficulty accepting the idea that anything but three dimensional
geometry is physical.
[Hammond]
Please avoid ad hominem remarks.
It's not an ad hominem remark. It's my impression of what you
don't understand.
[Hammond]
The Lorentz Transformation is a DIRECT RESULT of assuming that
"C is an invarient".
No, it isn't george. It's a direct consequence of having a
four dimensional spacetime with a metric -+++ or +---.
I.e. all you need to derive the Lorentz Transformation is to
assume C is the same to every inertial observer.
I'm sorry if the historical development wasn't the most direct
approach, but that's nothing I can fix. I can only take advantange
of the advances which have made the actual physics more obvious
and try not to get trapped by the same conceptual difficulties.
OK... once you derive the Lorentz Transformation, the "Minkowski
rotation" gemetry is mathematically obvious. However it is all
based on the ASSUMPTION that C is what is observed by every
inertial observer, regardless of his velocity. So far no physics
except the assumption that C is invarient.
No, it's not. The geometry is the geometry. What anyone assumes
about it, doesn't change the fact that nature chose the geometry
before anyone assumed anything.
Now.... however, you point out that the Lorentz Tranformation is
NECESSARY in order to formulate a "conserved current" namely
E^2-p^2=m^2
That _particular_ conserved quantity is a consequence of lorentz
invariance. For the galilean group, mass is _explicitly_ conserved.
If the galilean group correctly represented spacetime, there would
be no such thing as chemistry or nuclear binding.
(so called conservation of energy). Are you saying
then that the "postulate" of the invariance of C is PHYSICALLY
NECESSITATED by the requirement of the "conservation of energy".
If so, that sounds like a pretty hefty physical reason for
"postulating" that C is an invariant.
No. I said _explicitly_ that the lorentz transformations follow
from the first postulate alone. So do the galilean transformations
as a special case. It's the _same_ geometry, wit the exception
that the galilean group has an additional symmetry, which is
invariance under a galilean boost. That symmetry conserves the
mass explicitly. But the metric is essentially the same.
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| User: "Bill Hobba" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 03:15:19 AM |
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"George Hammond" <nowhere1@nospam.net> wrote in message
news:ss20h1tpiiaklv1kvmvsp279pgutvc40is@4ax.com...
On Sat, 27 Aug 2005 03:28:05 GMT,
(Bilge) wrote:
George Hammond:
Einstein's Special Relativity is famous for AD HOC
postulating that:
"All observers regardless of their relative
(uniform) velocities will measure the same
speed of light, C."
This is of course highly COUNTER INTUITIVE (the Galilean transformation
is more intuitive).
ODDLY ENOUGH, Einstein never gave a physical reason or explanation of
WHY C should be the same for all observers regardless of their speed...
he simply AD HOC POSTULATED the fact (which has since been
experimentally
confirmed a million times).
George ... I know you understand relativity well enough to know
the answer to this, so I'll assume you just need a brief refresher.
Recall that relativity is a theory of geometry, not electromagnetism,
so we can dispense with the light postulate altogether. Afterwords,
we can see under what conditions the light postulate would be correct.
Einstein's first postulate is sufficient to derive both special and
galilean relativity if we assume a four-dimensional space time with
a lorentzian manifold. Velocities are nothing more than a slope in
plane containing the t-axis. The fact that the t-axis has a different
sign than than the spatial axes, means that the lines at 45 degrees
in the (\beta = +/1) divide the spacetime into spacelike, timelike and
null intervals, with the lines at 45 degrees being null (or null cone
if you want to consider all four dimensions).
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
George the physical explanation is that space and time form a single
interconnected geometry. What Bilge showed is that this assumption - that
we live in a 4 dimensional space-time manifold - leads immediately to the
lorenzian metric (the others have consequences at variance with wheat we
observe) which implies SR and the existence of an invariant speed. That
this speed is the speed of light follows from other considerations such as
local charge conservation. Basically SR is a theory about space-time
geometry where space and time are treated on equal footing.
Thanks
Bill
[Hammond]
Let me ask you this:
Can an answer to the question:
What is the "reason" C is constant
to all (uniformly) moving observers?
be formulated by saying:
"Because apparently uniform motion
physically causes (for some unknown
but presumably explainable reason),
a PHYSICAL CONTRACTION of rulers,
and a PHYSICAL SLOWING of clocks;
such that the speed (distance/time)
of a light ray therefore remains a
universal CONSTANT."
Would that be considered a "physical explanation"
of the constancy of the speed of light for observers
moving relativly to each other... or is that to be
considered a circular explanation?
Or... is it true that "charge conservation" is actually the
cause of the invarience of C.
Or... might it be held that "charge conservation" is a result
of assuming C is invarient?
.
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| User: "Mike" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 07:42:06 PM |
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Bill Hobba wrote:
[snip]
George the physical explanation is that space and time form a single
interconnected geometry. What Bilge showed is that this assumption - that
we live in a 4 dimensional space-time manifold - leads immediately to the
lorenzian metric (the others have consequences at variance with wheat we
observe) which implies SR and the existence of an invariant speed. That
this speed is the speed of light follows from other considerations such as
local charge conservation. Basically SR is a theory about space-time
geometry where space and time are treated on equal footing.
Thanks
Bill
I do not think you and Bildge understand the question george posed and
you fail in a grand way to comprehend the difference between models and
laws.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve. Einstein was not
"pragmatic" as the naive Bildge thinks, he was clever enough to make
the right choice between framing unobservables, like geometry, and
adding an axiom. He chose the latter but naive, neo-relativists,
revisionist imbeciles, think that they can substitute geometry for an
axiom, without understanding the profound implications such unfounded
claim has on physical reality, implications that even Einstein seems to
have understood but the imbeciles do not, obviously.
Mike
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
02 Sep 2005 11:48:39 PM |
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Mike:
I do not think you and Bildge understand the question george posed and
you fail in a grand way to comprehend the difference between models and
laws.
I do understand the question and the question doesnt make sense
in the context in which it was asked. His question is _exactly_
the same as asking, ``why is a straight line the shortest distance
between two points in euclidean geometry.'' Change from three dimensions
with a metric of +++ to four dimensions with a metric of +---, and you
have george's question. It only makes sense to ask about the actual
speed of light in the context of a relativistic theory of electromagnetism.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve.
Name one.
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| User: "Ken S. Tucker" |
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| Title: Re: What is the "reason" C is constant to all observers? |
03 Sep 2005 01:01:33 AM |
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Bilge (poop for brains) wrote:
Mike:
I do not think you and Bildge understand the question george posed and
you fail in a grand way to comprehend the difference between models and
laws.
I do understand the question and the question doesnt make sense
in the context in which it was asked. His question is _exactly_
the same as asking, ``why is a straight line the shortest distance
between two points in euclidean geometry.'' Change from three dimensions
with a metric of +++ to four dimensions with a metric of +---, and you
have george's question. It only makes sense to ask about the actual
speed of light in the context of a relativistic theory of electromagnetism.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve.
Name one.
Your signature +--- fails in GR, it's only
introductory. Read a comic post 1908!
Follow-ups set to bilge enema's using his ear.
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
03 Sep 2005 04:57:07 AM |
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Ken S. Tucker, jargon swizzler:
Your signature +--- fails in GR, it's only
Prove it.
introductory. Read a comic post 1908!
Give up, ken. You obviously dont want to learn any physics, so
there must be something you can do with your time that would
be more useful than posting ***** to a newsgroup you have
no interest in. If not, you must lead a very dull life.
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| User: "brian a m stuckless" |
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| Title: Re: What is the "reason" C is constant to all observers? |
03 Sep 2005 07:35:57 AM |
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Bilge wrote:
I do understand the question and the question doesnt make
sense in the context in which it was asked.
Brian replies:
1. DO NOT RESPOND to NONsense QUESTiONs which you UNDERSTAND.
2. DO NOT RESPOND to UN-asked QUESTiONs by ASSUMMiNG iNTENTs.
STOP trying to be SO MUCH like poor jiM CARR-ied-to-far-away.
Pleaseeeeeeeeeeeeeee,
```Brian
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| User: "Mike" |
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| Title: Re: What is the "reason" C is constant to all observers? |
05 Sep 2005 10:57:17 AM |
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Bilge wrote:
Mike:
I do not think you and Bildge understand the question george posed and
you fail in a grand way to comprehend the difference between models and
laws.
I do understand the question and the question doesnt make sense
in the context in which it was asked. His question is _exactly_
the same as asking, ``why is a straight line the shortest distance
between two points in euclidean geometry.'' Change from three dimensions
with a metric of +++ to four dimensions with a metric of +---, and you
have george's question. It only makes sense to ask about the actual
speed of light in the context of a relativistic theory of electromagnetism.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve.
Name one.
Absolute space, of course. For to have a geometry, it must be
something.
Mike
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
05 Sep 2005 11:05:51 PM |
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Mike:
Bilge wrote:
Mike:
I do not think you and Bildge understand the question george posed and
you fail in a grand way to comprehend the difference between models and
laws.
I do understand the question and the question doesnt make sense
in the context in which it was asked. His question is _exactly_
the same as asking, ``why is a straight line the shortest distance
between two points in euclidean geometry.'' Change from three dimensions
with a metric of +++ to four dimensions with a metric of +---, and you
have george's question. It only makes sense to ask about the actual
speed of light in the context of a relativistic theory of electromagnetism.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve.
Name one.
Absolute space, of course. For to have a geometry, it must be
something.
Why is that?
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| User: "Hatunen" |
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| Title: Re: What is the "reason" C is constant to all observers? |
05 Sep 2005 01:33:03 PM |
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On 5 Sep 2005 08:57:17 -0700, "Mike" <eleatis@yahoo.gr> wrote:
Bilge wrote:
Mike:
I do not think you and Bildge understand the question george posed and
you fail in a grand way to comprehend the difference between models and
laws.
I do understand the question and the question doesnt make sense
in the context in which it was asked. His question is _exactly_
the same as asking, ``why is a straight line the shortest distance
between two points in euclidean geometry.'' Change from three dimensions
with a metric of +++ to four dimensions with a metric of +---, and you
have george's question. It only makes sense to ask about the actual
speed of light in the context of a relativistic theory of electromagnetism.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve.
Name one.
Absolute space, of course. For to have a geometry, it must be
something.
Euclid may have required it millenia ago, but today geometry
doesn't require a physical space; it is a mathematical abstract
which models absolute space sufficiently well to serve for
physical calculations. For small volumes of space Euclidean
geometry serves well, for large volumes Lobatchevskian works
better.
************* DAVE HATUNEN (hatunen@cox.net) *************
* Tucson Arizona, out where the cacti grow *
* My typos & mispellings are intentional copyright traps *
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| User: "Bilge" |
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| Title: Re: What is the "reason" C is constant to all observers? |
29 Aug 2005 09:40:40 AM |
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Mike:
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
It's not necessary to assume anything about ``reality.'' All you
have to do is assume _something_ and _use_ the assumptions to construct
a self-consistent explanation. If the explanation works and contains
no extraneous assumptions, then what other ``reality'' is there at
whatever level the explanation is designed to apply? I mean, geometry
is nothing more than a way to label and order observations with numbers
that satisfy a particular labeling scheme. If it makes you happy,
call it something else, like the SO(1,3) ordering scheme and pretend
there is some deep reality that no one can fathom in a lifetime of
sental masturbation sessions.
but you generate more problems than you solve. Einstein was not
"pragmatic" as the naive Bildge thinks, he was clever enough to make
the right choice between framing unobservables, like geometry, and
adding an axiom.
I don't have to be ``clever enough to make the right choice.'' I only
have to make _a_ choice and see if experiments are consistent with
my choice when applied in accordance with the definitions.
He chose the latter but naive, neo-relativists,
revisionist imbeciles, think that they can substitute geometry for an
axiom, without understanding the profound implications such unfounded
claim has on physical reality, implications that even Einstein seems to
have understood but the imbeciles do not, obviously.
So, how come the revisionist imbeciles have managed to come up
with explanations that agree with real observations? Dumb luck?
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| User: "Mike" |
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| Title: Re: What is the "reason" C is constant to all observers? |
29 Aug 2005 02:46:13 PM |
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Bilge wrote:
Mike:
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
It's not necessary to assume anything about ``reality.'' All you
have to do is assume _something_ and _use_ the assumptions to construct
a self-consistent explanation. If the explanation works and contains
no extraneous assumptions, then what other ``reality'' is there at
whatever level the explanation is designed to apply? I mean, geometry
is nothing more than a way to label and order observations with numbers
that satisfy a particular labeling scheme. If it makes you happy,
call it something else, like the SO(1,3) ordering scheme and pretend
there is some deep reality that no one can fathom in a lifetime of
sental masturbation sessions.
but you generate more problems than you solve. Einstein was not
"pragmatic" as the naive Bildge thinks, he was clever enough to make
the right choice between framing unobservables, like geometry, and
adding an axiom.
I don't have to be ``clever enough to make the right choice.'' I only
have to make _a_ choice and see if experiments are consistent with
my choice when applied in accordance with the definitions.
He chose the latter but naive, neo-relativists,
revisionist imbeciles, think that they can substitute geometry for an
axiom, without understanding the profound implications such unfounded
claim has on physical reality, implications that even Einstein seems to
have understood but the imbeciles do not, obviously.
So, how come the revisionist imbeciles have managed to come up
with explanations that agree with real observations? Dumb luck?
You are so clever to direct replies to alt.morons, imbecile Bildge. But
even a moronnow reading my reply will know I am talking about you.
Maybe we should forget about SR for a moment and try to help you
understand what Sophism means. You make a great sophist. Actually, you
could make a great lawyer but as far as physics, there is no room for
such play. So choose your discipline first and come back for a serious
conversation if you are willing to understand why you are wrong.
The first lesson for you is the distinction between laws and models.
The second lesson for you is the purpose of an axiomatic system and why
such system is not only useful but necessary for the consistency of a
theory.
learn logic. Start with first order. Understand the dinstiction between
rules, facts and conclusions. Comprehend the difference between
deduction and abduction, one you gloriously seemd to fail to
understand.
learn the difference between truth and validity
understand that single ecperiments cannot validate any principle but
only falsify it. You seem not to understand that. It is really
dissappointing. no principle gets any support from isolateed
experiments, unless you can prove there is no experiment that falsifies
it. God, why do I have to go through this now!
Oh, boy. the list can go for ever. You have so many things to learn
before you can claim you know something. Actually, if you just admit
you know nothing, I will agree you know something, that is you know
that you know nothing, ok sophist?
Mike
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| User: "George Hammond" |
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| Title: Re: What is the "reason" C is constant to all observers? |
28 Aug 2005 01:12:16 AM |
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On 27 Aug 2005 17:42:06 -0700, "Mike" <eleatis@yahoo.gr> wrote:
Bill Hobba wrote:
[snip]
George the physical explanation is that space and time form a single
interconnected geometry. What Bilge showed is that this assumption - that
we live in a 4 dimensional space-time manifold - leads immediately to the
lorenzian metric (the others have consequences at variance with wheat we
observe) which implies SR and the existence of an invariant speed. That
this speed is the speed of light follows from other considerations such as
local charge conservation. Basically SR is a theory about space-time
geometry where space and time are treated on equal footing.
Thanks
Bill
[Mike]
I do not think you and Bilge understand the question George posed and
you fail in a grand way to comprehend the difference between models and
laws.
[Hammond]
That is a correct assessment.
Conventionalism is an open issue. If you assume that physical reality
has a geometry then you can derive the constancy of the speed of light
but you generate more problems than you solve. Einstein was not
"pragmatic" as the naive Bilge thinks, he was clever enough to make
the right choice between framing unobservables, like geometry, and
adding an axiom. He chose the latter but naive, neo-relativists,
revisionist imbeciles, think that they can substitute geometry for an
axiom, without understanding the profound implications such unfounded
claim has on physical reality, implications that even Einstein seems to
have understood but the imbeciles do not, obviously.
[Hammond]
Affirmative... in that I concur with your assessment that
postulating "C is an invarient" has overwhelming DIRECT empirical
support... whereas postulating anything as indirect as "space-time is
a Lorentz manifold" certainly has no DIRECT SIMPLISTIC empirical
support.... it only has the indirect support of the empirical
observation that "C is an invarient"... from which it is then
mathematically DEDUCED!
Mike
[Hammond]
I agree with your thrust Mike.
In essence..... identifying a "postulate"... (doesn't matter what
postulate... but I advance the "invarince of C" is the simplest one
to confirm)... DOES NOT solve the dilemma of
providing a PHYSICAL EXPLANATION for said postulate (which ever
it may be).
SO.... I have advanced my own PHYSICAL EXPLANATION of
the "invariance of C" postualte (which can be shown to be equivalent
to any other SR postulate):
1. Fact is, that any two particles having dfferent velocities
MUST have been differentially accelerated at some time
in the past (otherwise how could they have different speeds).
2. Acceleration is resisted by INERTIA which as Mach and Einstein
have argued is caused by the gravitation of the entire universe
acting on the particle (Mach's Principle).
3. Inertial force (e.g. acceleration) then is a "compressive force"
which PHYSICALLY CAUSES the Lorentz contraction and
the time dilation. Note that this is a PHYSICAL EXPLANATION
for the SR contraction and time dilation.
4. The Lorentz contraction and time dilation are both proportional to
the acceleration, so thier ratio (length/time) results in an
invarient constant, and this constant is C... the speed of
light.
5. Therefore, it is INERTIA (which is another name for the universal
effect of gravitation) that PHYSICALLY CAUSES C to be a
universal invarient under (inertial) transformations.
This I claim is a "PHYSICAL EXPLANATION" of why C is an invariant,
as opposed to a simple "postulate" that C is invariant... or even
opposed to a experimental confirmation that C is an invarient.
So I say it is INERTIA which is the PHYSICAL CAUSE of C being an
invarient under inertial coordinate transformations.
Morevover, it would also "physically explain" Einstein's
OTHER famous postulate of (General) Relativity... the "equivalence
principle". The PHYSICIAL REASON that:
Gravitational mass = Inertial mass
is simply that INERTIA is caused by GRAVITY!
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| User: "Mike" |
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| Title: Re: What is the "reason" C is constant to all observers? |
28 Aug 2005 11:38:45 AM |
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George Hammond wrote:
[snip]
SO.... I have advanced my own PHYSICAL EXPLANATION of
the "invariance of C" postualte (which can be shown to be equivalent
to any other SR postulate):
1. Fact is, that any two particles having dfferent velocities
MUST have been differentially accelerated at some time
in the past (otherwise how could they have different speeds).
This is a resoanable statement that passes verification.
2. Acceleration is resisted by INERTIA which as Mach and Einstein
have argued is caused by the gravitation of the entire universe
acting on the particle (Mach's Principle).
Actually, I think Mach claimed inertia is caused by mass distribution
in the universe. whereas the Newtonian view 9as interpreted
subsequently and not necessarily of Newton himself) is that inertia is
an inherent quality of bodies. But I do not think, and I maybe wrong,
that Mach went as far as postulating that gravitation causes inertia.
3. Inertial force (e.g. acceleration) then is a "compressive force"
which PHYSICALLY CAUSES the Lorentz contraction and
the time dilation. Note that this is a PHYSICAL EXPLANATION
for the SR contraction and time dilation.
Let us accept for a moment this hypothesis, because it is only a
hypothesis and try to see whether it leads to contradictions.
4. The Lorentz contraction and time dilation are both proportional to
the acceleration, so thier ratio (length/time) results in an
invarient constant, and this constant is C... the speed of
light.
This is a new hypothesis and will be treated together with the first.
5. Therefore, it is INERTIA (which is another name for the universal
effect of gravitation) that PHYSICALLY CAUSES C to be a
universal invarient under (inertial) transformations.
Now, you have introduced the concept of causality in your hypotheses
and conclusion. The problem that arises is the following: if time
dilation and length contraction are due to acceleration, i.e. the
latter is the cause of the first two, then why is it that when there is
no force acting on a particle and it is moving at a constant velocity,
these effects persist?
In another words, why is it that when the cause is removed, the effect
still remains as validated by several experiments?
This I claim is a "PHYSICAL EXPLANATION" of why C is an invariant,
as opposed to a simple "postulate" that C is invariant... or even
opposed to a experimental confirmation that C is an invarient.
But the explanation rests on at least two unproven hypotheses.
So I say it is INERTIA which is the PHYSICAL CAUSE of C being an
invarient under inertial coordinate transformations.
Petitio Principii
Morevover, it would also "physically explain" Einstein's
OTHER famous postulate of (General) Relativity... the "equivalence
principle". The PHYSICIAL REASON that:
Gravitational mass = Inertial mass
is simply that INERTIA is caused by GRAVITY!
This is an interesting statement. Many thought it is the opposite, like
for instance Feynman once said that gravity could be a force that is
due to the choice of reference frame. the problem with such statement
is that it leads to unbservable physics. There can be no experiment in
which a body can move without the infuence of gravitational force so it
cannot be falsified.
Therefore, as much as Mach's claim, such statement will remain in the
realms of philosophy with no possibility of ever proving or disproving
it.
Mike
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| User: "George Hammond" |
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| Title: Re: What is the "reason" C is constant to all observers? |
28 Aug 2005 09:02:22 PM |
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On 28 Aug 2005 09:38:45 -0700, "Mike" <eleatis@yahoo.gr> wrote:
George Hammond wrote:
[snip]
SO.... I have advanced my own PHYSICAL EXPLANATION of
the "invariance of C" postualte (which can be shown to be equivalent
to any other SR postulate):
1. Fact is, that any two particles having dfferent velocities
MUST have been differentially accelerated at some time
in the past (otherwise how could they have different speeds).
This is a resoanable statement that passes verification.
[Hammond]
It's not original with me... it's been known for a long time
and I read it soewhere years ago.
2. Acceleration is resisted by INERTIA which as Mach and Einstein
have argued is caused by the gravitation of the entire universe
acting on the particle (Mach's Principle).
Actually, I think Mach claimed inertia is caused by mass distribution
in the universe. whereas the Newtonian view 9as interpreted
subsequently and not necessarily of Newton himself) is that inertia is
an inherent quality of bodies. But I do not think, and I maybe wrong,
that Mach went as far as postulating that gravitation causes inertia.
[Hammond]
Yes he did postulate that Inertia is caused by the gravitation
of all the other bodies in the universe... and Einstein even
agreed with the idea.
3. Inertial force (e.g. acceleration) then is a "compressive force"
which PHYSICALLY CAUSES the Lorentz contraction and
the time dilation. Note that this is a PHYSICAL EXPLANATION
for the SR contraction and time dilation.
Let us accept for a moment this hypothesis, because it is only a
hypothesis and try to see whether it leads to contradictions.
4. The Lorentz contraction and time dilation are both proportional to
the acceleration, so thier ratio (length/time) results in an
invarient constant, and this constant is C... the speed of
light.
This is a new hypothesis and will be treated together with the first.
5. Therefore, it is INERTIA (which is another name for the universal
effect of gravitation) that PHYSICALLY CAUSES C to be a
universal invarient under (inertial) transformations.
Now, you have introduced the concept of causality in your hypotheses
and conclusion. The problem that arises is the following: if time
dilation and length contraction are due to acceleration, i.e. the
latter is the cause of the first two, then why is it that when there is
no force acting on a particle and it is moving at a constant velocity,
these effects persist?
[Hammond]
That's a good question and one for which there is no obvious answer.
In fact there are several such problems. For instance... if Inertia
is caused by gravitation from distant bodies.... how come Inertia
responds instantaneously to accleration while gravity only
propagates at the (finite) speed of light. This is the basic problem
with Mach's Principle itself and has been the basic problem for
100 years. Nevertheless Mach's Principle is STILL the leading
candidate for the explanation of Intertia... ever since Einstein
himself said he thought it was. See for instance:
http://chaos.fullerton.edu/~jimw/general/inertia/
Note that the "inertial mass" of an accelerated object DOES change
instantaneously in response to acceleration and STAYS that way
even after the acceleration stops. This is probably the clue to the
answer to your question, but again, the problem has not been solved.
By the way.... I certainly have no vested interest in defending
this theory.... I'm simply pointing out that it is (apparently) the
only known plausible candidate for a so called "physical answer" to
the question of why "the speed of light is an invarient" to all
inertial observers. Relativity after all DOES NOT OFFER an answer
to that question.... all Relativity says it that "C IS AN
INVARIENT"... it offers no physical explanation of WHY it SHOULD
be an invarient.
And by the way, obviously these questions are not going to be
answered by anyone who is not a first rank theoretical physicist
and an authority in Relativity, as can easily be judged by reading
Dennis Sciama's paper cited in the URL above. I am certainly not
such a person and neither is anyone else on theis NG... I simply
point out that the theory I have sketched is the "most plausible"
candidate for a "physical explanaion" of why C is an anvariant.
In another words, why is it that when the cause is removed, the effect
still remains as validated by several experiments?
[Hammond]
Yes... this is a question that would have to be answered... but it
is not implausible that it would given that the inertial mass of the
object itself is increaded during acceleration and "remains in effect
even after the cause has been removed".
Obviously the so called "compressive force" that would cause the
length contarction is not an ordinary force in the sense of clamping
the object in a vice or something.... apparently the electromagnetic
forces of structure in the object are permanently affected in some
way which causes the shortening. Lorentz by the way, when he was
searching for a "physical explanation" of the SR contraction before
Einstein positied SR actually pro0osed that the spherical field of the
electrons actually became "elliptical" due to "ether drag".
Interestingly even though the ether theory turns out to be wrong..
the "elllipsoidal field" of the electrons is still actually observed
in SR as a result of the Lorentz Transformation. Apparently
Lorentz (who the Lorentz Transformation is named after by the
way, may not have been completely off base with his ether theory..
only perhaps it is "Inertia" which takes the place of the Ether?
This I claim is a "PHYSICAL EXPLANATION" of why C is an invariant,
as opposed to a simple "postulate" that C is invariant... or even
opposed to a experimental confirmation that C is an invarient.
But the explanation rests on at least two unproven hypotheses.
[Hammond]
Of course... it is only an intuition or suspicion on my part, nothing
more.. and nothing of any real relevance or importance to my work
in the first place. More a matter of curiosity than anything else.
HOWEVER, I do think it is imporant to point out that Relativty in
general DOES NOT PROVIDE ANY PHYSICAL EXPLANATION OF WHY
C IS AN INVARIENT UNDER INERTIAL TRANSFORMATIONS....
SOME PEOPLE SEEM TO BE UNAWARE OF THAT
all Relativity does is tell you WHAT the answer is, it does
NOT TELL YOU "WHY" THE ANSWER IS
Anyway, I wouldn't spend any serious time investigating the problem
since the answer to the problem is really not connected in any serious
way to my own work, nor it is an area in which I am an expert. It's
just a suggestion, or rather an observation on my part.
So I say it is INERTIA which is the PHYSICAL CAUSE of C being an
invarient under inertial coordinate transformations.
Petitio Principii
Morevover, it would also "physically explain" Einstein's
OTHER famous postulate of (General) Relativity... the "equivalence
principle". The PHYSICIAL REASON that:
Gravitational mass = Inertial mass
is simply that INERTIA is caused by GRAVITY!
This is an interesting statement. Many thought it is the opposite, like
for instance Feynman once said that gravity could be a force that is
due to the choice of reference frame. the problem with such statement
is that it leads to unbservable physics. There can be no experiment in
which a body can move without the infuence of gravitational force so it
cannot be falsified.
[Hammond]
Well... it seems there is enough of a proble with Mach's Principle to
make the problem of Inertia insoluble at the moment... at least in the
opinion of experts like Sciama and Wheeler. So maybe I should back
off in my speculations on it's relation to the Equivalence Principle.
Where exactly the question of the origin of inertia comes into the
Equivalence Principle is not really clear to me.
Therefore, as much as Mach's claim, such statement will remain in the
realms of philosophy with no possibility of ever proving or disproving
it.
Mike
[Hammond]
given the progress that Sciama and Wheeler and many others have made
on M<ach's Princile as the origin of Inertia, I would bet that the
question of finding a "physical explanation" of why C is an invarient
to all inertial observers will ultimately be solved.
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| User: "" |
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| Title: Re: What is the "reason" C is constant to all observers? |
28 Aug 2005 01:24:29 AM |
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INERTIA is caused by GRAVITY!
***************
This is correct. Inertia is gravity tugging at all the widdle
thingy-poos in the Universe. Ramanujan knew this.
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| User: "George Hammond" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 04:47:10 AM |
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On Sat, 27 Aug 2005 08:15:19 GMT, "Bill Hobba" <rubbish@junk.com>
wrote:
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
George the physical explanation is that space and time form a single
interconnected geometry.
[Hammond]
I am well aware that that is a RESULT of Relativity, it cannot be
called a CAUSE however.
the direct cause of the Lorentz Transformation is the ASSUMPTION
that the speed of Light is the same for all inertial observers
regardless of their velocity. this then results immediately
in the Lorentz Transformation.... and the Lorentz Transformation
then results in our "geometric 4-axis rotation geometry" of
Relativity.
the question is.... what is the "physical cause" of the invariance of
C. Bilge has suggested (if I read him right) that the constancy of C
is NECISSITATED by the requirement of the "conservation of energy",
i.e. in order to formuklate the "conserved current" E^2-p^2=m^2.
If this is correct, then we can say that "the conservation of energy"
is the CAUSE of C being an invarient.
You suggest that it is the "conservation of charge".. perhaps... but
certainly the "conservation of energy" would be a sufficient physical
reason.
What Bilge showed is that this assumption - that
we live in a 4 dimensional space-time manifold - leads immediately to the
lorenzian metric
[Hammond]
Na... you don't have to "postulate" a 4D space-time manifold... all
you have to do is postulate that C is an invarient... which is what
Einstein did in 1905.
(the others have consequences at variance with wheat we
observe) which implies SR and the existence of an invariant speed.
[Hammond]
the existence of the "4-D space-time manifold" is the MATHEMATICAL
RESULT of simply assuming that C is an invariant... which is what
Einstein postulated... and the existence of the "4-D space-time
manifold" followed as a mathematical consequence.
That
this speed is the speed of light follows from other considerations such as
local charge conservation.
[Hammmond]
Bilge seems to think it comes from the "conservation of energy".
It may come from both... however the conservation of energy
seems to be a more massive pillar of physics than mere charge
conservation.
Basically SR is a theory about space-time
geometry where space and time are treated on equal footing.
[Hammond]
Mathematically that's what it turns out to be... however it is
the basic PHYSICAL postulates such as "inertial covariance",
"invariance of C" which are the PHYSICAL CAUSES of this
mathematical "description" of Relativity.
Thanks
Bill
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| User: "Bill Hobba" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 07:55:48 PM |
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"George Hammond" <nowhere1@nospam.net> wrote in message
news:oic0h154rqcj1if8qhggdqaqq1in2shl1n@4ax.com...
On Sat, 27 Aug 2005 08:15:19 GMT, "Bill Hobba" <rubbish@junk.com>
wrote:
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
George the physical explanation is that space and time form a single
interconnected geometry.
[Hammond]
I am well aware that that is a RESULT of Relativity, it cannot be
called a CAUSE however.
George that is the point of Bilges post. SR can be derived from that
assumption. The situation is this - SR implies space-time geometry -
space-time forms a geometry ie a manifold implies SR.
the direct cause of the Lorentz Transformation is the ASSUMPTION
that the speed of Light is the same for all inertial observers
regardless of their velocity. this then results immediately
in the Lorentz Transformation.... and the Lorentz Transformation
then results in our "geometric 4-axis rotation geometry" of
Relativity.
George please read the links I have given in another post.
the question is.... what is the "physical cause" of the invariance of
C. Bilge has suggested (if I read him right) that the constancy of C
is NECISSITATED by the requirement of the "conservation of energy",
i.e. in order to formuklate the "conserved current" E^2-p^2=m^2.
That is not what Bilge has suggested. He suggested that the assumption that
space-time forms a manifold leads immediately to SR and the prediction that
there is an invariant speed.
If this is correct, then we can say that "the conservation of energy"
is the CAUSE of C being an invarient.
George I am sure you are aware that conservation of energy is simply a
special case of Noethers theorem and is really a tautological statement
about the symmetries of a systems lagrangian.
Thanks
Bill
You suggest that it is the "conservation of charge".. perhaps... but
certainly the "conservation of energy" would be a sufficient physical
reason.
What Bilge showed is that this assumption - that
we live in a 4 dimensional space-time manifold - leads immediately to the
lorenzian metric
[Hammond]
Na... you don't have to "postulate" a 4D space-time manifold... all
you have to do is postulate that C is an invarient... which is what
Einstein did in 1905.
(the others have consequences at variance with wheat we
observe) which implies SR and the existence of an invariant speed.
[Hammond]
the existence of the "4-D space-time manifold" is the MATHEMATICAL
RESULT of simply assuming that C is an invariant... which is what
Einstein postulated... and the existence of the "4-D space-time
manifold" followed as a mathematical consequence.
That
this speed is the speed of light follows from other considerations such as
local charge conservation.
[Hammmond]
Bilge seems to think it comes from the "conservation of energy".
It may come from both... however the conservation of energy
seems to be a more massive pillar of physics than mere charge
conservation.
Basically SR is a theory about space-time
geometry where space and time are treated on equal footing.
[Hammond]
Mathematically that's what it turns out to be... however it is
the basic PHYSICAL postulates such as "inertial covariance",
"invariance of C" which are the PHYSICAL CAUSES of this
mathematical "description" of Relativity.
Thanks
Bill
.
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| User: "George Hammond" |
|
| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 10:11:43 PM |
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On Sun, 28 Aug 2005 00:55:48 GMT, "Bill Hobba" <rubbish@junk.com>
wrote:
"George Hammond" <nowhere1@nospam.net> wrote in message
news:oic0h154rqcj1if8qhggdqaqq1in2shl1n@4ax.com...
On Sat, 27 Aug 2005 08:15:19 GMT, "Bill Hobba" <rubbish@junk.com>
wrote:
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
[Hobba]
George the physical explanation is that space and time form a single
interconnected geometry.
[Hammond]
I'll say it again.
That is not a CAUSE of "C beinf invarient",
it is a RESULT of C being invarient.
....since C being invarient is an experimentally discovered fact,
and the "Lorentz manifold" is NOT an experimentally discovered
fact.
[Hammond]
I am well aware that that is a RESULT of Relativity, it cannot be
called a CAUSE however.
[Hobba]
George that is the point of Bilges post. SR can be derived from that
assumption. The situation is this - SR implies space-time geometry -
space-time forms a geometry ie a manifold implies SR.
[Hammond]
Naw... you cannot call the POR anything more than a "postulate"..
on the other hand the invariance of C is an EXPERIMENTAL FACT, and is
sufficent to derive the Lorence Transformation and all of SR.
Therefore the invariance of C is an "experimentally verified
postularte"... whereas the POR is just a postulate.
the direct cause of the Lorentz Transformation is the ASSUMPTION
that the speed of Light is the same for all inertial observers
regardless of their velocity. this then results immediately
in the Lorentz Transformation.... and the Lorentz Transformation
then results in our "geometric 4-axis rotation geometry" of
Relativity.
George please read the links I have given in another post.
[Hammond]
No. I already have an M.S. in Relativity and have already heard the
whole story from the horse's mouth ages ago.
the question is.... what is the "physical cause" of the invariance of
C. Bilge has suggested (if I read him right) that the constancy of C
is NECISSITATED by the requirement of the "conservation of energy",
i.e. in order to formuklate the "conserved current" E^2-p^2=m^2.
[Hobba]
That is not what Bilge has suggested. He suggested that the assumption that
space-time forms a manifold leads immediately to SR and the prediction that
there is an invariant speed.
[Hammond]
You're going around in circles.
We do not need "more postulates" such as "spacetime forms a 4D Lorentz
manifold"... which fact is a SIMPLE MATHEMATICAL CONSEQUENCE of
the experimentally verified postulate that C is an invarient.
If this is correct, then we can say that "the conservation of energy"
is the CAUSE of C being an invarient.
[Hobba]
George I am sure you are aware that conservation of energy is simply a
special case of Noethers theorem and is really a tautological statement
about the symmetries of a systems lagrangian.
[Hammond]
Yeah.. sure. Point is, I am looking for a "physical explanation" of:
1. Why C is invarient.
and NO POSTULATE is going to physically explain it other than being
a "MATHEMATICAL CONSEQUENCE OF SAID POSTULATE".
ON THE OTHER HAND, I will here propose a PHYSICAL EXPLANATION
of why C is an invarient:
1. Fact is, that any two particles having dfferent velocities
MUST have been differentially accelerated at some time
in the past.
2. Accleration is resisted by INERTIA which as Planck and Einstein
have argued is caused by the gravitation of the entire universe
acting on the particle.
3. Inertial force (e.g. accleration) then is a "compressive force"
which PHY7SICALLY CAUSES cause the Lorentz contraction and
the time dilation. Note that this is a PHYSICAL EXPLANATION
for the SR contraction and time dilation.
4. The Lorentz contraction and time dilation are such that they cause
C to be a constant for any (inertial) observer.
5. Therefore, it is INERTIA (which is another name for the universal
effect of gravitation) that PHYSICALLY CAUSES C to be a universal
invarient under (inertial) transformations.
Christ.... I finally had to answer my own question!
Thanks
Bill
Thanks so much, George.
.
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| User: "Bill Hobba" |
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| Title: Re: What is the "reason" C is constant to all observers? |
27 Aug 2005 11:10:47 PM |
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|
"George Hammond" <nowhere1@nospam.net> wrote in message
news:n792h15be91kvflrv40a2p9nnj02klbbkn@4ax.com...
On Sun, 28 Aug 2005 00:55:48 GMT, "Bill Hobba" <rubbish@junk.com>
wrote:
"George Hammond" <nowhere1@nospam.net> wrote in message
news:oic0h154rqcj1if8qhggdqaqq1in2shl1n@4ax.com...
On Sat, 27 Aug 2005 08:15:19 GMT, "Bill Hobba" <rubbish@junk.com>
wrote:
[Hammond]
Yes.. we are all familiar with the "geometric description" of
SR....... but that is simply a CONSEQUENCE of ad-hoc presuming
that the speed of light is a constant to any observer regardless of
his velocity.
what I want to know is, is therey andy "physical" explanation
for the invarience of C.
[Hobba]
George the physical explanation is that space and time form a single
interconnected geometry.
[Hammond]
I'll say it again.
That is not a CAUSE of "C beinf invarient",
it is a RESULT of C being invarient.
...since C being invarient is an experimentally discovered fact,
and the "Lorentz manifold" is NOT an experimentally discovered
fact.
George I do not understand your logic here. If we assume the POR then
making no assumption at all about light we can derive the Lorentz
transformations up to an undetermined value of c. The second axiom is
required to fix that value at the speed of light - that is its only purpose.
However one does not have to use the second axiom to do that. As one of the
papers I linked you to says http://arxiv.org/abs/physics/0110076,
'We have found the form of transformation functions between two frames in
the standard configuration. The only remaining unknown is the value of the
universal constant u. From the transformation functions we can make a number
of conclusions, for example about possibility of time dilation. Then we
could use time dilation experiments (involving decay of stationery and
moving mesons) to measure the value of u. Another (but not the only) way to
find a value of u by deriving velocity addition formula and observing that
if c^2 = -u and an object moves with speed c in one inertial frame, then it
moves with the same speed in all others. This would enable us to identify c
as the speed of light in vacuum. But I stress once again that other
experiments could be used to find the value of the constant.'
Imagine I have used one of those experiments such as the decay time of
mesons to determine the value of the constant. We measure it and notice to
within experimental accuracy it is the same as the speed of light. A
question arises natualrally, and it is the question you are asking - why is
this so? There are many reasons:
1. Maxwell's equations must be invariant from the POR - this implies
immediately the value of c must be the speed of light - providing of course
Maxwell's equations are true.
2. The others I listed in my first post eg gauge symmetry and local charge
conservation.
The above are the reasons the value of the constant that appears in the
Lorentz transformations should be the speed of light. It is not an
assumption - it is a consequence of any of those physical principles being
true eg EM gauge invariance.
[Hammond]
I am well aware that that is a RESULT of Relativity, it cannot be
called a CAUSE however.
[Hobba]
George that is the point of Bilges post. SR can be derived from that
assumption. The situation is this - SR implies space-time geometry -
space-time forms a geometry ie a manifold implies SR.
[Hammond]
Naw... you cannot call the POR anything more than a "postulate"..
Of course it is a postulate - all theories are built on postulates. It is
however one with strong experimental support.
on the other hand the invariance of C is an EXPERIMENTAL FACT, and is
sufficent to derive the Lorence Transformation and all of SR.
Yes George, up to experimental accuracy what you say is true. But its
validity is exactl | | | | | | | |
