Bill Hobba wrote:
Just to elaborate a little of what David said. Do not be confused that such
violates the POR by defining a preferred inertial frame. The CBMR defines a
preferred frame for certain purposes; but such a frame is not strictly
inertial so the POR is not violated - it is pretty close to inertial - but
we are speaking on matters of principles here.

I wouldn't say that at all. Yes indeed, the CMBR does not violate the
PoR (in the context of SR). But that's because it is essentially an
object (a set of radiation), and there's no problem with an object
having a specific rest frame (or in the case of the CMBR, a dipole=0 frame).

For instance, it is quite easy to determine the locally-inertial frame
in which the fixed stars are at rest, if one looks at them. But in a
closed room in freefall (far from any other objects like the earth or
sun) it is not possible to determine that frame. Similarly for the CMBR
dipole=0 frame -- without observing the CMBR one cannot determine it. So
it does not violate the PoR (of SR).


Tom Roberts

"Tom Roberts" wrote in message
news
Bill Hobba wrote:

Just to elaborate a little of what David said. Do not be confused that
such violates the POR by defining a preferred inertial frame.
The CBMR defines a preferred frame for certain purposes;

Then such a coordinate system can be defined for any and all purposes.

but such a frame is not strictly inertial

What evidence do you have for this arbitrary claim, Bill?

so the POR is not violated - it is pretty close to inertial -
but we are speaking on matters of principles here.

Yeah, the 'principle' that Bill can't bear the thought that his Religion is
on shaky ground.

I wouldn't say that at all. Yes indeed, the CMBR does not violate the
PoR (in the context of SR). But that's because it is essentially an
object (a set of radiation), and there's no problem with an object
having a specific rest frame (or in the case of the CMBR, a dipole=0
frame).

The two approaches are amusing. Bill realizes the problem, so simply
declares that the CMBR is not 'inertial' on principle. Tom accepts the
inertial situation, but resorts to redefining a sea of uncorrelated photons
as a single 'object'.

For instance, it is quite easy to determine the locally-inertial frame
in which the fixed stars are at rest, if one looks at them.

Really, Tom? How does one do this .... specifically? How many stars do you
use? Which ones? And what about the Great Attractor?

But in a
closed room in freefall (far from any other objects like the earth or
sun) it is not possible to determine that frame. Similarly for the CMBR
dipole=0 frame

-- without observing the CMBR one cannot determine it.

Well, duh! But one *can* determine the single, local inertial coordinate
system by observing the CMBR. Which invalidates SR.

So it does not violate the PoR (of SR).

The PoR is violated if a single, coordinate system *can* be observed. It
doesn't go away if we shut our eyes (or put ourselves in a closed room).

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

"Tom Roberts" wrote in message
...
Paul Stowe wrote:
On Tue, 12 Oct 2004 11:29:25 GMT, "Kenneth Ellested"
wrote:
Sorry for asking but what is:
1. LET

[L]orentz's [E]lectrodynamic [T]heory based upon his 1904 paper

What we call LET around here is a synthesis from Lorentz's writings, and
not any specific theory he himself described.

Here Tom again trots out his 'what we call LET' speech. Tom's orginal term
for this ever-changning Relativst strawman was "Absolute Almost-SR."
However, it contains nothing whatsoever from either Lorentz or from any
aether theory:
http://www.google.com/groups?selm=10....supernews.com

Let's look at what Tom orginally had to say about his "Absolute Almost-SR"
(now called by him "LET"). It's odd, that Tom originally was quite
reasonably hesitant to call this mish-mash "LET". Both Alan Pendleton and
Tom Roberts agree that there is (or was) *not* a generally-accepted name for
Tom's "Absolute Almost SR":
===========================
Alan Pendleton:
"I don't know that there is a generally accepted name for this theory. It
has been going by Lorentz Ether Theory (LET) in these parts."

Tom Roberts:
"Yes, I know that. I chose a generic name because 1) I have not had the time
to look up Lorentz's papers (and I am not about to rely on descriptions in
sci.physics.relativity). 2) I believe that LET has exact Lorentz symmetry,
and I wanted to include potential theories which include only approximate
Lorentz Symmetry (even though I have no idea how to consistently express
such a theory)."
===========================

Tom later got suckered into using a 'nonstandard' name for a made-up theory.
Now he shills for it.

Now, let us look at the explicit assumptions of Tom's "Absolute Almost-SR":
=========================
Tom Roberts:
"Now let us consider another potential theory to which I will give the
provocative title 'Absolute Almost-SR'. While I have not seen a modern
exposition of this, it would clearly echo the thoughts of Maxwell and
Lorentz. This theory would assert there is an absolute reference frame,
that light propagates isotropically at velocity c only in the absolute
frame, and that length contraction and time dilatation conspire to produce
results indistinguishable from 'Weak SR' for observations such as 1 and 2
above* as long as the absolute velocity of the lab is very much smaller than
c."

*The experimental evidence for "Weak SR" is extensive. I will merely
summarize two major classes of experimental observations:

1.No matter how much energy is pumped into a particle, it never
goes faster than c. Moreover, the relationship between velocity
and energy is in excellent agreement with SR (either "Weak SR"
or "Strong SR").
2.High-energy mesons travel very much farther than the product of
their measured lifetimes and their velocity. Moreover, their
mean travel distance correlates with their energy in good
agreement with SR ("Weak" or "Strong").
http://www.google.com/groups?selm=5v....ih.lucent.com
=========================

Although Tom claims that his Absolute Almost-SR "clearly echo the thoughts
of Maxwell and Lorentz", Tom admits that he has read nothing of Lorentz to
this effect. (He apparently also hadn't read Maxwell's works.) So his
claim is pure wishful thinking.

According to Tom, the explicit assumptions of Absolute Almost-SR a
1. "There is an absolute reference frame."
2. "Light propagates isotropically at velocity c only in the absolute
frame."
3. "Length contraction and time dilatation conspire to produce results
indistinguishable from 'Weak SR'."

None of these three assumptions exist anywhere in the writings of either
Maxwell or Lorentz. Neither Lorentz nor Maxwell used an absolute reference
frame in any of their writings. None of these assumptions exists in any
aether theory either.

So it is trivially a result of postulate #3 that Tom constantly preaches
that "LET is indistinguishable from SR".

It is clear that the only "Lorentz" in Absolute Almost-SR is the assumption
of Einsteinian "Lorentz Transforms" contained within assumption 3. And
Lorentz never used the Einsteinian "Lorentz Transforms" that -- perhaps
unfortunately -- bear his name.

http://www.google.com/groups?selm=10....supernews.com

It is really based on the
1915 edition of Lorentz's _Theory_of_Electrons_[#].

As is clear from Tom's own writings, Absolute Almost-SR has nothing
whatsoever to do with Lorentz' writings. Of 1915 or anywhere else.

http://www.google.com/groups?selm=10....supernews.com

===========================
Tom Roberts:
"Yes, for a while I did accept greywolf42's and Stowe's claim that 'LET' is
described by Lorentz's 1904 paper."

greywolf42:
"It is. That Lorentz wrote additional works concerning electron theory does
not change Lorentz Electrodynamic Theory (LET)."

Tom Roberts:
"I was complicit in a major goof -- "

greywolf42:
"Tom, the whole thrust of our past disagreements was that you made up an
SR-doppleganger that you labeled "Lorentz Ether Theory" -- even though you
had never read Lorentz. And you have -- up until this post -- VEHEMENTLY
asserted that your creation was Lorentz' work, and used it as a strawman."
===========================

The point being that Lorentz never had an 'ether theory' remotely like the
"Absolute Almost-SR" theory that Tom uses.


In the notes of that
edition he acknowledges the superiority of Einstein's approach, and the
better definition of \rho by Poincare'.

LOL! You'll note that Tom doesn't provide a quote. IIRC, what Lorentz says
is 'simpler', not 'superior'.

[#} What Lorentz meant by "electron" is not what we mean by
that word today.

Horsefeathers. An electron is an electron. They were well known by 1915.
That the standard theory model (point charge) is different than the simple
spherical model that Lorentz used doesn't change the meaning of the word --
or the object described by that word!

Specifically, with the definition of charge density (\rho) of Lorentz's
1904 paper, charge is not conserved in a moving system, contrary to
observations here on earth. Poincare's definition resolves that
discrepancy. In this way, LET becomes experimentally indistinguishable
from SR. It also becomes mathematically equivalent to SR, in that any
theorem of either theory is a theorem of both; some would say that makes
them the same theory, but IMHO that is merely a matter of opinion about
what the word "theory" means.

Absolute Almost-SR has nothing whatsoever to do with Lorentz's writings. Tom
is decent enough to eventually slog his way through Lorentz' actual writings
(after his nose has been rubbed in his own willful ignorance enough).
Unfortunately, his entire effort is focused on justifying his old claims
that "Lorentz Ether Theory" comes from Lorentz' writings. It finally dawned
on Tom (after many fruitless repeats of authoritative claims) that Lorentz'
work of 1904 is not the same as Absolute Almost-SR (which Tom now insists on
calling "Lorentz Ether Theory".) He finally figured out that there *IS* a
substantive difference between Lorentz' 1904 work and SR. So now he's
switched making unsubstantiated claims about Lorentz' 1915 work.

However, the point remains that what Tom (and other Relativists) call "LET"
is nothing more than a strawman doppleganger for SR, used solely to buttress
SR.

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

"Tom Roberts" wrote in message
news
Bill Hobba wrote:
Just to elaborate a little of what David said. Do not be confused that
such
violates the POR by defining a preferred inertial frame. The CBMR
defines a
preferred frame for certain purposes; but such a frame is not strictly
inertial so the POR is not violated - it is pretty close to inertial -
but
we are speaking on matters of principles here.

I wouldn't say that at all. Yes indeed, the CMBR does not violate the
PoR (in the context of SR). But that's because it is essentially an
object (a set of radiation), and there's no problem with an object
having a specific rest frame (or in the case of the CMBR, a dipole=0
frame).

Yes I see your point. What I was trying to get at is that thing (the
radiation) will have gravity associated with it hence the frame would not be
inertial. But your explanation is even more fundamental eg if one was in
free fall then it would be locally inertial CBMR or no CBMR. Thanks for
pointing it out.


For instance, it is quite easy to determine the locally-inertial frame
in which the fixed stars are at rest, if one looks at them.


As is well known.

But in a
closed room in freefall (far from any other objects like the earth or
sun) it is not possible to determine that frame. Similarly for the CMBR
dipole=0 frame -- without observing the CMBR one cannot determine it. So
it does not violate the PoR (of SR).

Got it. Thanks for clarifying it.

Thanks
Bill



Tom Roberts

"greywolf42" wrote in message
m...
"Tom Roberts" wrote in message
news
Bill Hobba wrote:

Just to elaborate a little of what David said. Do not be confused
that
such violates the POR by defining a preferred inertial frame.
The CBMR defines a preferred frame for certain purposes;

Then such a coordinate system can be defined for any and all purposes.

but such a frame is not strictly inertial

What evidence do you have for this arbitrary claim, Bill?

A frame containing the CBMR would create a gravitational field. But what I
had forgotten is the principle of equivalence - even in that case if one is
in free fall then it would locally be inertial.


so the POR is not violated - it is pretty close to inertial -
but we are speaking on matters of principles here.

Yeah, the 'principle' that Bill can't bear the thought that his Religion
is
on shaky ground.

Not really.

Thanks
Bill


I wouldn't say that at all. Yes indeed, the CMBR does not violate the
PoR (in the context of SR). But that's because it is essentially an
object (a set of radiation), and there's no problem with an object
having a specific rest frame (or in the case of the CMBR, a dipole=0
frame).

The two approaches are amusing. Bill realizes the problem, so simply
declares that the CMBR is not 'inertial' on principle. Tom accepts the
inertial situation, but resorts to redefining a sea of uncorrelated
photons
as a single 'object'.

For instance, it is quite easy to determine the locally-inertial frame
in which the fixed stars are at rest, if one looks at them.

Really, Tom? How does one do this .... specifically? How many stars do
you
use? Which ones? And what about the Great Attractor?

But in a
closed room in freefall (far from any other objects like the earth or
sun) it is not possible to determine that frame. Similarly for the CMBR
dipole=0 frame

-- without observing the CMBR one cannot determine it.

Well, duh! But one *can* determine the single, local inertial coordinate
system by observing the CMBR. Which invalidates SR.

So it does not violate the PoR (of SR).

The PoR is violated if a single, coordinate system *can* be observed. It
doesn't go away if we shut our eyes (or put ourselves in a closed room).

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

Kenneth Ellested:
The historical reasons for special relativity have little to
do with the reasons it's used today.
OK, but I thought the speed of light would be constant to the ether if such
a thing existed.
Therefore there would only be one inertial frame (as far as I can
understand), which actually would make the universe a little easier to
understand for the "average" kook 8-|

It's not workable unless you relegate the ether to some symbolic baggage.
Can you be more specific - what doesn't work?

Try defining the mechanical properties of the ether so that light
propagates as a _transverse_ wave. If you try doing that, you'll
find that the ether doesn't even serve the purpose for which it was
originally proposed.

[...]
You can accept whatever you want. Whether or not you're a kook depends
upon your reasons for doing so.

As far as I have read there was actually some kind of "battle" between
Miller and Einstein. It seems that Einstein was not found of Millers work,
and with the help of Shankland it later became "history". Thats the short
version, but its interesting to read the story, and also get a glimse of the
private letters from Einstein to Miller.

It makes no difference whether or not einstein was fond of ``miller's
work''. Einstein was not fond of quantum mechanics either and made no
secret of that fact, yet quantum mechanics has not been disregarded.
Einstein spent the last half of his life trying to create a unified theory
built upon general relativity, yet no one has followed that approach.

The fact is that the michelson-morely experiment and millers experiments
are irrelevant and the primary value of the michelson-morely experiment is
historical perspective. The acceptance of relativity did not result from
a single experiment. For example, I never agonized over interpreting the
michelson-morely experiment. I saw relativity in action every day in
lab where I worked as an undergraduate and graduate student. Quite
frankly, I find it rather odd that the error bars in any 100 year old
experiment would be given any significance. Anyone with a few dollars,
some experimental know-how and mechanical aptitude could do those exper-
iments today, better than either michelson and morely or miller did them.

I for sure, don't know if an "ether" exists or not, but the M&M inferometer
looks to me like it will probably always produce a "null" result (concerning
wave mechanics only, though I'm not an expert), and as far as I can tell,
this was the main reason for totally rejecting the "ether" at the time.

Most ether advocates spend all of their effort trying devise schemes to
isure that regardless of what relativity implies, the result will be null.
On the other hand, it's hard to find an ether theory in which someone
starts with any mechanical properties of the ether and derives relativity.
In general it's a retrofit in which the ether serves as a container to
hold a list of ``features'', none of which would be consistent with the
purpose of a mechanical medium for which the ether was originally proposed.

What's even worse, is that if you assume for the sake of argument that
some ether theory worked, it still doesn't address the physics at the
fundamental level. All it does is explain one interaction in terms of
another one which the theory doesn't explain and as far as I can tell,
is supposed to be taken on faith as unknowable.

Instead we got Einsteins relativity which is quite hard to imagine, even
that it might be the truth.

If you look carefully at how a semiconductor works, you will probably
find that even hrder to imagine. That's also going to be the case for
anything that involves phenomena that are outside the regime of everyday
experience.

I do however have huge problems with relativity, especially that the
speed of light is constant to any inertial frame (which (as I understand)
it had to, since an ether wasn't detected).

Why should the speed of light not be constant, apart from your extra-
polation from personal experience with velocities ranging from about
0.0000000 c to 0.0000001 c? Physics studies phenomena at the extremes.
The nucleus of an atom for example has a density of about 10^17 kg/m
a temperature on the order of 10^10 K, a speed of sound around c/3 and
collision times on the order of 10^-22 seconds. If you try to imagine
that in familiar terms, you'll probably find that hard to believe, too.

With an ether model this problem would be solved in a way that makes more
sense to me (at least), so that's why I'm trying to figure what exactly
rejected this model, why it was rejected and why it still is. And if I find
the answer, this may make even more sense.

The ether model was ultimately rejected because physicists found that
it made less sense to force nature to fit anthropocentrically based
preconceptions about nature than it did to examine those preconceptions,
especially when it became obvious that no ether would be able to
act as the mechanical substance for which it was originally conceived.
The ether in any ``viable'' ether theory would still be an abstraction
of a substance that actually bears no resemblence to the physical
materials to which it is an analogy, so I can't see that one gains
any physical intuition from an ether theory that would be compatible
with nature.

Anyway, I learn something new by investigating this further - I can highly
recommend it (not only to kook's)!

I don't think there's much to be gained by looking at ancient data,
except perhaps some insight into data reduction and error analysis.
That might be useful, if you are trying to read data from the error
bars.

"Bilge" skrev i en meddelelse
...
Kenneth Ellested:
The historical reasons for special relativity have little to
do with the reasons it's used today.
OK, but I thought the speed of light would be constant to the ether if
such
a thing existed.
Therefore there would only be one inertial frame (as far as I can
understand), which actually would make the universe a little easier to
understand for the "average" kook 8-|

It's not workable unless you relegate the ether to some symbolic
baggage.
Can you be more specific - what doesn't work?

Try defining the mechanical properties of the ether so that light
propagates as a _transverse_ wave. If you try doing that, you'll
find that the ether doesn't even serve the purpose for which it was
originally proposed.
I haven't actually thought of a mechanical description, and that there
should only be room for longitudinal waves in such a model. Please elaborate
a little. How will a transverse wave offend the ether model as you see it?
From your reply I can clearly see that you know a lot more than I do, I'm
just trying to figure what's between me and the stars. If there's nothing I
wonder how I can see the light. I don't actually care wether it's one thing
or another, but I like to call this something the "ether" and so far I'm
pretty sure that there must be something in between us for which a
photon/wave can propagate through. This is probably a very
"mechanical/natural" approach, but thats how my mind works.

[...]
You can accept whatever you want. Whether or not you're a kook depends
upon your reasons for doing so.

As far as I have read there was actually some kind of "battle" between
Miller and Einstein. It seems that Einstein was not found of Millers
work,
and with the help of Shankland it later became "history". Thats the short
version, but its interesting to read the story, and also get a glimse of
the
private letters from Einstein to Miller.

It makes no difference whether or not einstein was fond of ``miller's
work''. Einstein was not fond of quantum mechanics either and made no
secret of that fact, yet quantum mechanics has not been disregarded.
Einstein spent the last half of his life trying to create a unified theory
built upon general relativity, yet no one has followed that approach.
Maybe it is impossible to build this upon GR?

The fact is that the michelson-morely experiment and millers experiments
are irrelevant and the primary value of the michelson-morely experiment is
historical perspective. The acceptance of relativity did not result from
a single experiment. For example, I never agonized over interpreting the
michelson-morely experiment. I saw relativity in action every day in
lab where I worked as an undergraduate and graduate student. Quite
frankly, I find it rather odd that the error bars in any 100 year old
experiment would be given any significance. Anyone with a few dollars,
some experimental know-how and mechanical aptitude could do those exper-
iments today, better than either michelson and morely or miller did them.
You sound like you are very settled on a particular theory, and I think this
is the right thing to do as long as it answers your questions. I hope I will
also reach to an understanding of the universe some day.
But a thing that sometimes puzzles me is why the principles of relativity
still beeing tested by new experiments with professional physicists. To me
it seems like some physicists believes there is ether a lack of evidence or
confidence, but that's just how it seems.

I for sure, don't know if an "ether" exists or not, but the M&M
inferometer
looks to me like it will probably always produce a "null" result
(concerning
wave mechanics only, though I'm not an expert), and as far as I can tell,
this was the main reason for totally rejecting the "ether" at the time.

Most ether advocates spend all of their effort trying devise schemes to
isure that regardless of what relativity implies, the result will be null.
On the other hand, it's hard to find an ether theory in which someone
starts with any mechanical properties of the ether and derives relativity.
In general it's a retrofit in which the ether serves as a container to
hold a list of ``features'', none of which would be consistent with the
purpose of a mechanical medium for which the ether was originally
proposed.
I try to have an open mind, and I'm not against relativity, ether or xyz - I
just can't imagine how relativity works... which is due to my limitted
ability of only beeing able to think in "natural" physics.

What's even worse, is that if you assume for the sake of argument that
some ether theory worked, it still doesn't address the physics at the
fundamental level. All it does is explain one interaction in terms of
another one which the theory doesn't explain and as far as I can tell,
is supposed to be taken on faith as unknowable.

Instead we got Einsteins relativity which is quite hard to imagine, even
that it might be the truth.

If you look carefully at how a semiconductor works, you will probably
find that even hrder to imagine. That's also going to be the case for
anything that involves phenomena that are outside the regime of everyday
experience.
Well apart from having a background in electronics I see your point.
But I still find relativity a lot harder to "imagine" than semiconductors,
atomic models, silicon impurities etc.
The only time my mind have been equally challenged is when I as a kid had to
imagine that the Universe was infinite.
I still don't accept "infinite" as an answer, but I've learned to live with
it. I can also add "what was before Big Bang".

I do however have huge problems with relativity, especially that the
speed of light is constant to any inertial frame (which (as I understand)
it had to, since an ether wasn't detected).

Why should the speed of light not be constant, apart from your extra-
polation from personal experience with velocities ranging from about
0.0000000 c to 0.0000001 c? Physics studies phenomena at the extremes.
The nucleus of an atom for example has a density of about 10^17 kg/m
a temperature on the order of 10^10 K, a speed of sound around c/3 and
collision times on the order of 10^-22 seconds. If you try to imagine
that in familiar terms, you'll probably find that hard to believe, too.
Well, I'm personally fine with a constant speed of light, only not in every
inertial frame.
It somehow twists my mind with an endless loop of questions and
constellations.

With an ether model this problem would be solved in a way that makes more
sense to me (at least), so that's why I'm trying to figure what exactly
rejected this model, why it was rejected and why it still is. And if I
find
the answer, this may make even more sense.

The ether model was ultimately rejected because physicists found that
it made less sense to force nature to fit anthropocentrically based
preconceptions about nature than it did to examine those preconceptions,
especially when it became obvious that no ether would be able to
act as the mechanical substance for which it was originally conceived.
The ether in any ``viable'' ether theory would still be an abstraction
of a substance that actually bears no resemblence to the physical
materials to which it is an analogy, so I can't see that one gains
any physical intuition from an ether theory that would be compatible
with nature.
What is the difference between "ether" and "foam" (to me it seems like it is
the century)?

Anyway, I learn something new by investigating this further - I can
highly
recommend it (not only to kook's)!

I don't think there's much to be gained by looking at ancient data,
except perhaps some insight into data reduction and error analysis.
That might be useful, if you are trying to read data from the error
bars.
Excuse me, but this sounds a little biased. However, I find it important to
investigate our history (not data sheets in particular).

Regards

On Thu, 14 Oct 2004 06:04:58 GMT, "Bill Hobba" wrote:


"greywolf42" wrote in message
om...
"Tom Roberts" wrote in message
news
Bill Hobba wrote:

Just to elaborate a little of what David said. Do not be confused
that
such violates the POR by defining a preferred inertial frame.
The CBMR defines a preferred frame for certain purposes;

Then such a coordinate system can be defined for any and all purposes.

but such a frame is not strictly inertial

What evidence do you have for this arbitrary claim, Bill?

A frame containing the CBMR would create a gravitational field. But what I
had forgotten is the principle of equivalence - even in that case if one is
in free fall then it would locally be inertial.


so the POR is not violated - it is pretty close to inertial -
but we are speaking on matters of principles here.

Yeah, the 'principle' that Bill can't bear the thought that his Religion
is
on shaky ground.

Not really.

In the minds of the devout their religon is NEVER on
shaky ground...

Paul Stowe

"Bill Hobba" wrote in message
...

"greywolf42" wrote in message
m...
"Tom Roberts" wrote in message
news
Bill Hobba wrote:

Just to elaborate a little of what David said. Do not be confused
that
such violates the POR by defining a preferred inertial frame.
The CBMR defines a preferred frame for certain purposes;

Then such a coordinate system can be defined for any and all purposes.

but such a frame is not strictly inertial

What evidence do you have for this arbitrary claim, Bill?

A frame containing the CBMR would create a gravitational field.

Not the frame, but the energy of the CMBR would create a gravitational
field.

But what
I had forgotten is the principle of equivalence - even in that case if one
is in free fall then it would locally be inertial.

Since the CMBR is presumed to exist throughout all the universe, where is
the 'local' aspect of the inertial frame?

{snip}
--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

Kenneth Ellested:
"Bilge" skrev i en meddelelse


Try defining the mechanical properties of the ether so that light
propagates as a _transverse_ wave. If you try doing that, you'll
find that the ether doesn't even serve the purpose for which it was
originally proposed.
I haven't actually thought of a mechanical description, and that there
should only be room for longitudinal waves in such a model.

The problem is not that materials only support longitudinal waves,
since many materials _do_ support transverse waves. The problem is
that, transverse oscillations require a restoring force perpendicular
to the propagation direction, which means you're dealing with a solid.
You can picture this as a series of planes which transfer energy by
sliding alongside each other. Eventually, you find that spacetime has
be stiffer than any known material, which makes one wonder why we
don't notice this, given that we interact electromagnetically, just like
light does. One ill-conceived response has been to say that the ether
is a superfluid and superfluids support transverse waves. Well, that
is rather misleading, since exactly one superfluid, 3He(B), supports a
transverse oscillation and the mechanism by which it does so also
introduces a number of other types of oscillations, none of which have
been observed and none of which could be described by maxwell's equations.
Other difficulties with that analogy are that the dispersion is
temperature dependent, and there obviously exists a transition temperature
above which the the transverse mode spontaneously disappears. Finally,
3He(B) is a fermion, and invariably, those proposing the analogy have
no real idea what that means, so the analogy appears to be more a product
of quote mining through google than any actual theory.

[...]
photon/wave can propagate through. This is probably a very "mechanical/
natural" approach, but thats how my mind works.

Unfortunately, nature doesn't give us the option of understanding
things on our terms. Sometimes you just have to put preconceptions
aside and try looking at nature differently. In this case the initial
impression that relativity isn't ``natural'', will go away and a lot
of physics that appears to be disjoint or ad hoc will seem rather
natural.

It makes no difference whether or not einstein was fond of ``miller's
work''. Einstein was not fond of quantum mechanics either and made no
secret of that fact, yet quantum mechanics has not been disregarded.
Einstein spent the last half of his life trying to create a unified theory
built upon general relativity, yet no one has followed that approach.

Maybe it is impossible to build this upon GR?

My guess is that is the general consensus, since most everyone in the
gravity business is working on quantum theories of gravity rather than
general relativistic theories of quantum mechanics. However, I'm not
a general relativity theorist, it's possible they might be able to point
you to someone still pounding away on einsteins original unified field
theory.


some experimental know-how and mechanical aptitude could do those exper-
iments today, better than either michelson and morely or miller did them.
You sound like you are very settled on a particular theory, and I think this
is the right thing to do as long as it answers your questions.

Let me put it this way. At some level, special relativity is obviously
wrong, since it doesn't describe gravity. At some level, general
relativity is probably also not the correct theory for describing the
universe. Most likely, general relativity is a low energy effective
theory, (where ``low energy'' means the temperature of the universe was
below about 10^30 K). However, the comparisons I'm making apply to regimes
in which an ether theory is supposed to act as a functional replacement
for relativity. So, basically, you might say that I'm settled on which
theories are incorrect as far as relativity goes, which is to say at any
level that any concept of space and time make sense. Since I don't know of
nor can imagine any ether theory describing what the universe might be
like when the concept of any geometry becomes questionable, I certainly
don't see an ether theory as being a theory from whence relativity sprang.
So, I could certainly believe in a number of different theories as some
ultimate theory, but the ether isn't one of those theories nor do
I find it solves more problems than it creates at any level.

I hope I will
also reach to an understanding of the universe some day.
But a thing that sometimes puzzles me is why the principles of relativity
still beeing tested by new experiments with professional physicists.

A couple reasons, but it sort of depends upon what you mean by ``prin-
ciple of relativity''. It's probably safe to say that most physicists are
not testing it in the sense that physics depends upon where you are in the
universe. What's more likely is what is being tested are things like
whether the speed of light is constant, which in and of itself is not
important to relativity. Other things which have been proposed are
theories like ``doubly special relativity'' and others in which the
lorentz transforms take on a somewhat different form. Some of those turn
out to be conformally equivalent to special relativty, some are not. The
unprecedented and unexpected success of the standard model in correctly
predicting all of the experiments done so far, means that physicists have
spent a lot more time trying to find some effect that cannot be explained
by the standard model or general relativity than trying to figure out how
to do an experiment to verify an obvious prediction. The standard model
has a number of parameters that are fixed by experiment but are not
themselves predictions of the standard model. Unfortunately, the standard
model offers no obvious clues as to where to look in trying to explain
those parameters. Some modification to relativity might provide a
clue.

To me it seems like some physicists believes there is ether a lack
of evidence or confidence, but that's just how it seems.

I really don't think those tests to which you refer are tests
of relativity in the sense you mean. There might be some, but
I'm not aware of any.

[...]
In general it's a retrofit in which the ether serves as a container to
hold a list of ``features'', none of which would be consistent with the
purpose of a mechanical medium for which the ether was originally
proposed.

I try to have an open mind, and I'm not against relativity, ether or xyz - I
just can't imagine how relativity works... which is due to my limitted
ability of only beeing able to think in "natural" physics.

It's most natural to think of relativity as geometry. You have to
picture spacetime as ``laid out'' in both time and space, rather than
space with you moving through it time. Ether advocates choose a 3-d
geometry without requiring themselves to explain that choice, so there is
no reason to not simply choose four-dimensional spacetime as a geometry
from the start. Either both choices require further explanations or neither
does. Presumably, nature wasn't constrained by our preconceptions.

In 3-d space, the distance between two points is,

ds^2 = (dx_1)^2 + (dx_2)^2 + (dx_3)^2

In spacetime, the same relationship is,

ds^2 = -(dx_0)^2 + (dx_1)^2 + (dx_2)^2 + (dx_3)^2

where x_0 means t, and x_1, x_2, x_3 mean x, y, z. Apart from the minus
sign, those are conceptually identical. I left out the `c' on purpose,
since that detracts from the geometric aspect and is a human feature.
(you can replace the x_0 or t by ct if that helps, but doing so is
equivalent to replacing y by ay, i,e., it's a superfluous artifact of
choosing different units to measure different directions.) A spatial
rotation in a plane in either case is given by,

x' = x cos(A) - y sin(A) = cos(A)[x - y tan(A)]
y' = y cos(A) + x sin(A) = cos(A)[y + x tan(A)]

The slope of a line in terms of the original coordinates is
m = tan(A).

In special relativity, a rotation in the x-t plane (and similarly,
the y-t and z-t planes) is given by,

t' = t cosh(A) - x sinh(A) = cosh(A)[t - x tanh(A)]
x' = x cos(A) + t sinh(A) = cosh(A)[x - t tanh(A)]

The slope of a line in terms of the riginal coordinates is
m = tanh(A), just as above, except that it's tanh instead of
tan. However, these hyperbolic functions have additional
names: \beta = tanh(A), \gamma = cosh(A), \gamma\beta = sinh(A).

In other words, tanh(A) is a velocity (usually written as
v/c). cosh(A) is 1/sqrt(1 - (v/c)^2). You could write similar
expressions for the rotations in a plane. In relativity, when
you talk about some observer moving at some velocity, what you
are really saying is that the observer is rotated through an
angle given by v/c = tanh(A) relative to you.

If you look carefully at how a semiconductor works, you will probably
find that even hrder to imagine. That's also going to be the case for
anything that involves phenomena that are outside the regime of everyday
experience.

Well apart from having a background in electronics I see your point.
But I still find relativity a lot harder to "imagine" than semiconductors,
atomic models, silicon impurities etc.

Then you might see how familiarity results in less discomfort. On the
other hand, I think that given an equal lack of familiarity, most people
would find the concept of an electron hole pair being lifted from a fermi
surface and the idea of a hole moving around just like a particle, to be
rather bizarre if they you tried to explain it as more than just an
analogy. Having an electric field that sweeps holes into the collector of
a transistor probably sounds pretty strange to someone trying to figure
out how a transistor works without knowing anything about semiconductors.

The only time my mind have been equally challenged is when I as a kid had to
imagine that the Universe was infinite.
I still don't accept "infinite" as an answer, but I've learned to live with
it. I can also add "what was before Big Bang".

Well, I'm not going to say that imgining those things will be made
any easier by understanding relativity or anything else. I'll will say
that introducing an ether doesn't do anything but introduce more things
which are no easier to imagine, but mostly doesn't address them.


that in familiar terms, you'll probably find that hard to believe, too.
Well, I'm personally fine with a constant speed of light, only not in every
inertial frame.

It somehow twists my mind with an endless loop of questions and
constellations.

Well, here's the problem with saying ``not in every inertial frame''.
Inertial frames are all equivalent. What's true in one frame is either
true in every frame or the frames aren't equivalent. If frames are not
equivalent, then there exists some physical difference between them. If
no such difference can be determined experimentally, then there is no
physical effect that can depend upon some hypothetical difference,
since any physical effect would constitute an experiment, by definition.
If no physical effect can be attributed to such a hypothetical difference,
it really doesn't mean much to hypothesize it since it can't contribute
to any physics in this universe other than whatever physics goes along
with someone's philosophical satisfaction.

[...]
of a substance that actually bears no resemblence to the physical
materials to which it is an analogy, so I can't see that one gains
any physical intuition from an ether theory that would be compatible
with nature.

What is the difference between "ether" and "foam" (to me it seems
like it is the century)?

If you read a paper on something like spin ``foams'', you'll discover
that ``foam'' could not possibly have been chosen as a metaphor for
a substance in any ordinary meaning of the word, even if you stretch
it a lot. Here's a description of such a model,

http://arxiv.org/abs/gr-qc/9905087

The abstract reads, in part, ``Similarly, a spin foam is a 2-dimensional
complex with faces labelled by representations and edges labelled by
intertwining operators.'' It's clearly not a ``thing'' in any usual
sense of the word ``thing'', unless you're a mathematician or mathematical
physicist. Essentially, one shouldn't think of any quantum mechanical
entity, as a ``thing'' in any any usual sense of the word.


I don't think there's much to be gained by looking at ancient data,
except perhaps some insight into data reduction and error analysis.
That might be useful, if you are trying to read data from the error
bars.

Excuse me, but this sounds a little biased. However, I find it
important to investigate our history (not data sheets in particular).

If you'll note, I did say that the experiment is of historical interest.
From an historical perspective, one might also ask lots of other
questions, like, ``did the experiment convice people of the right theory
for the wrong reason'', etc. But I wasn't addressing the historical angle,
although it might be interesting. I was addressing the value of the data
in assessing anything about relativity. That data is essentially
irrelevant and doesn't really answer the question, since anyone could
postulate an ether theory that avoids a null result (which is another
problem with the ether. It has no definite properties that can be stated
as a starting point. The properties are a backfit to data that with no
self-consistency requirement, since anything can be a property of the
ether.)

The best way to understand the michelson-morely experiment is to perform
it yourself. It doesn't have to be a state-of-the-art experiment and
performing one, even badly, it a lot more educational than just reading
about it. I would guess that one could perform the experiment much better
than michelson and morely without a great deal of expense, especially if
one has access to a machine shop with even mediocre machines and one can
do the machining. It's pretty easy to hold tolerances of a few mils on
almost any lathe or milling machine that actually works. One doesn't have
to rely on a gas discharge lamp, since lasers are relatively cheap and
you can avoid the experimental error of having to read off measurements
visually by using optical sensors or ccd arrays. Similarly, if one can
program a microcontroller, one could rotate the apparatus with a stepping
motor and obtain repeatable postioning.