Re: Relativity as an axiomatic system
From: John Kennaugh (JKNG_at_kennaugh2435hex.freeserve.co.uk)
Date: 11/16/04
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Date: Tue, 16 Nov 2004 21:42:09 +0000
Patrick Reany writes
>John Kennaugh <JKNG@kennaugh2435hex.freeserve.co.uk> wrote in message
>news:<jbLQikF9m8kBFwbP@kennaugh2435hex.freeserve.co.uk>...
>> Bilge writes
>> >
>> > Light was postulated to propagate at `c', because (1) maxwell's
>> >equations were believed to be correct,
>>
>> There is not and never was a problem regarding light travelling at c.
>> The question is whether it 'propagates' in a medium or not. Maxwell
>> believed that his equations represented light travelling in the ether.
>
>Let's not forget that to Maxwell the ether was not just a name for a
>convenient feel-good ghost. To him it referred to a plenum of the
>largest mechanical object in the universe. It was mechanical! Such a
>model is hard to account for. For example, why doesn't it seem to
>interefer with the motions of ordinary matter. Why hasn't it caused
>the planets to decay in their orbits and they end up in the sun?
I am not saying you are wrong but I would (in my ignorance perhaps) have
assumed that Maxwell's equations opened up the possibility that instead
of a mechanical ether (a solid stiffer than steel) that the ether was an
electrical ether of some sort. I would have thought that the idea that
light was electrical disturbances rather than mechanical ones would make
a difference, open up other possibilities.
>Another embarrasing question is why the rest frame of the ether is
>whatever it is, given that it had an infinite number of possible
>inertial frames it could have chosen among?
That really isn't a problem. You have been working with relativity too
long and FoR have started to become 'real' to you. They are simply
mathematical abstractions. If there is an ether in the Lorentz sense
there is only one physical frame of reference which everything moves
relative to.
>> If you decide there is no ether (not unreasonable in view of MMX)
>
>Wrong! The human mind is creative enough to invent any ad hoc
>hypothesis to assume the existence of anything, yet account for the
>failure of any experiment.
I didn't say that was the only decision one could make only that it was
not an unreasonable one to make.
>The MMX forces us to decide not between
>what is possible and what is impossible, but between what is
> And to question the
>role that the PoR has in physical theory invention, if any.
MMX was a cross roads of physics or more like a T junction. By far the
simplest explanation is that there is no ether, that therefore
a source is surrounded by nothing which can affect the speed of light so
the speed of light (c from Maxwell's equations) is the speed relative to
the source there being nothing else it can be w.r.t i.e. source
dependence.
When you add the fact that light is made up of particles thrown out by
atoms when an atom sheds energy then there is no logical reason to
suppose that its speed is not a result of the physical process which
ejects it. Again if light is made of particles there is no need for an
ether so the fact that MMX hadn't found one is no embarrassment. That
then is the 'no ether' route taken by Ritz until his untimely death in
1909.
Lorentz chose the other route. He wouldn't accept the no ether
alternative and came up with a 'fix' which was LET. That retained the
ether and with it the belief in source independence. Whichever way you
look at it Einstein is further down the same road as Lorentz. Poncere
had speculated that the PoR might somehow make the ether disappear but
it was only speculation.
In Sir Edmund Whittaker's The History of Theories of Aether and
Electricity, published in 1953, apparently there is a chapter on
relativity, entitled, "The Relativity Theory of Poincare and Lorentz."
Einstein isn't mentioned until the thirteenth page and is credited with
adding the Doppler and aberration equations. Einstein was trying to
improve on Lorentz which is why his theory inherits the idea of source
independence but it has no theoretical basis without ether and no
empirical basis either.
One cannot keep asserting, as Einstein did, that Lorentz's explanation
is wrong without providing an alternative. While in 1905 Einstein may
have believed he would come up with one in 1920 his ideas re an ether
without the immobility of Lorentz's are vague to say the least. In the
end he declared relativity a 'principle theory' one which does not
attempt to provide physical explanations. Whether there is or isn't an
ether then becomes the type of question relativity does not attempt to
answer. I do not go along with the modern view which says "we have the
maths, a physical interpretation is superfluous" it is a cop-out.
If you take Lorentz ether theory, but don't include the theory, (the
physical interpretation) you don't get a simpler theory, you get an
incomplete theory. A mathematical model without a physical
interpretation. That is SR.
As for "the simplest of two or more possible explanations". Ritz had the
simplest explanation. LET is the alternative and SR is LET without any
physical interpretation.
>> then
>> it is no longer clear what the speed c of Maxwell's equations is w.r.t.
>
>The speed of c or any other speed is ALWAYS a speed with respect to
>some reference body of ponderable matter,
Agreed
> ie., a frame of reference.
I see a case of semantic slippage. Not *a* FoR but *the* FoR defined by
*the* ponderable matter.
>In that way the rest frame of the ether has no special kinematic role
>to play in physics. What makes LET special is not that it doesn't
>ultimately use relative speeds (all speeds are relative to something).
>What is special about LET is that is chooses just one rest frame as
>special, and in that in frame, and in it alone, do the undistorted
>"laws of physics" truly apply (i.e., rods and clocks behave "normally"
>in only that frame).
OK
>Einstein changed to very concept of a "law of
>physics."
? bit missing - doesn't make sense as written
>I have been saying this for years now, but nobody has got it
>yet. The laws of phsyics are not to be conceived of as have existnece
>only in a single frame of reference, but to all inertial frames. That
>was his contribution with SR.
The laws of physics are the same for all inertial frames in no way rules
out the possibility that in all FoR the speed of light is found to be
constant w.r.t the source. You said yourself "The speed of c or any
other speed is ALWAYS a speed with respect to some reference body of
ponderable matter." The most obvious ponderable matter which c could be
relative to is the source. There is no causal relationship which would
make it constant w.r.t anything else. Your perfectly sensible statement
becomes nonsense in relativity in that it requires that c be w.r.t two
different bits of ponderable matter travelling relative to each other in
the same bit of space.
The first postulate follows from the PoR. The second in Einstein's own
words is '... apparently incompatible with it'. What Einstein in affect
said is "Here is the deal. If you want to retain belief in source
independence, universal time [an axiom of physics at that time] will
have to go. You will have to accept that time is a function of relative
velocity." Now that is one hell of a big step. It is hard to reconcile
with "The simplest of two or more possible explanations" and what I
cannot understand is why it was felt that belief in source independence
was so important to retain that Einstein's offer was accepted. If they
believed in the ether what was wrong with Lorentz's theory? If they
didn't believe in the ether then why would they be so eager to retain a
belief in source independence which came from a belief in the ether and
from nowhere else? Only perhaps for the wrong reasons of a reluctance to
admit they had been wrong for 200 years.
> With GR he removed any lack of symmetry
>for the laws of physics to apply in. In GR, ALL possible frames of
>reference have the same laws of physics alive in them.
>
>> There only is the source, the observer, and the space in between.
>
>I point out that that's an arbitrary ontology, not necessarily
>reality. We don't really know what the universe is made out of and we
>can never know.
>
OK "as far as we know based on what is observable there only is the
source, the observer, and the space in between".
>> If you
>> rule out the space in between as not containing anything which can
>> affect the speed of light you are left with the source and the observer.
>> One should rule out the observer on the grounds of causality so the only
>> logical interpretation is that c is the speed relative to the source.
>>
>> Anyway what's it got to do with Maxwell? His equations are about light.
>> Relativity is not about light - Bilge told me :o)
>
>Relativity is a framework to view the general laws of physics, so it
>has everything to do with every thing that is presumed or imagined to
>have some effect on physical phenomena, and that includes the
>measureable behavior of light.
Only a gentle joke at Bilge's expense. Einstein's 1905 paper mentions
light 47 times and geometry (Euclidean as it happens) once but according
to Bilge relativity is about geometry not about light.
>
>[snip]
>
>> The principle of relativity, is an acceptance that MMX (and other
>> experiments) were destined to have a null result.
>
>Obviously, since if the PoR is to maintian that the laws of physics as
>viewed by all inertial observers are the same for all inertial
>observers, then, if there is a maximum speed in one frame, it must be
>the same maximum for all inertial observers. But a maximum speed
>invalidates the Galilean transformations of coordinates.
I see no reason to assume a theoretical maximum speed for light any more
than there is a maximum speed for running the mile. The absence of a
constant limit does not imply a limit of infinity. There are many
mathematical series which increase with every term, can have an infinite
number of terms but tend towards a finite limiting case. If you take the
ballistic case then if in every FoR the law is that the speed of light
is c relative to the source then the maximum speed likely to be observed
is c+v. There are no theoretical limit to the value of v a source could
attain in the observer's FoR but there are practical difficulties.
Limits to available energy. If one believes in the big bang then the
speeds which were attainable then will never be attainable again.
The BB theory doesn't work if relativity is assumed but as you say
>The human mind is creative enough to invent any ad hoc
>hypothesis to assume the existence of anything, yet account for the
>failure of any experiment.
rather than let BB fail they invented inflation, dark energy and dark
matter. I don't suppose anyone said "let us suppose relativity is wrong
and ballistic theory is right - see if that adds up". Matter might be
thrown out at speeds of several times c. What we would see is a fairly
uniform universe with a visual horizon limited to matter travelling away
from us at nearly c. Any matter travelling more than that we will never
see. Matter near the limit of what can be observed is travelling at
nearly c away from us and so its light is travelling towards us at c-v
where v is nearly c. It takes 14 billion years to reach us because it is
travelling so slow so what we see is the universe 14 billion years ago.
>
>
>[snip]
>
>Lack of time did not allow me to comment on the rest of what you
>wrote, but I did agree strongly with one part of it: To Einstein, the
>issue was not the presumed or formally introduced ether per se. His
>problem was with a mechanical ether.
Not entirely his main problem was the idea that the fixed ether made one
FoR unique. It is not the nature (mechanical or otherwise) which makes
Lorentz's ether work conceptually but the very fact that it provides a
unique reference, if an undetectable one, for all velocity.
There is a profound philosophical problem with no ether or any ether
concept which does not provide a fixed reference which can be
illustrated as follows:
A S
B--->v
Two observers A (stationary w.r.t the source S) and B (moving towards
the source S at v), see a flash of light from S as they pass. Lorentz's
theory says that light will travel at c relative to the ether FoR but
because of their different speeds relative to the ether A and B's
instruments will be differently affected and they will both end up
determining a numerical value for the speed of light as c. Because their
instruments are differently affected they will also calculate different
times for the event at S.
Note that the function of the ether is to distort a single reality so
that A and B have different perceptions of it.
Take away the ether and you have nothing to distort the instruments of
A and B. If their instruments are not distorted then if they each
determine that the speed of light from S as c it is because it *is* c so
it must have left S at c relative to S to go to A and at c-v relative to
S to go to B. If they compute different times for the event it is
because it actually took place at different times. In other words
without Lorentz's ether to distort a single reality you have two
different realities not merely different perceptions.
The implication/ physical interpretation is that A and B are in separate
universes. In A's universe A is stationary with respect to the
propagating medium and in B's he is stationary w.r.t the propagating
medium there is no problem about the light leaving the source at a
different time in one universe compared to the other.
If you are a mathematician rather than a scientist you will quite
happily equate what I describe as a 'separate universe' with a separate
FoR, and you will make my 'observer stationary w.r.t the propagating
medium' as just a property of that FoR but if you are a scientist
looking for a physical interpretation a FoR won't do. It is a
mathematical abstraction. It has no physical clout to sustain a separate
physical reality separate to another physical realities nor the physical
property to make light travel at c relative to itself. It can only do
those things to the equations describing those realities and that
property.
The alternative to Lorentz's ether is therefore an infinite number of
parallel universes each with its own ether.
-- John Kennaugh to email convert the number from hex to decimal
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