🚀 go-pugleaf

On Wed, 30 Jan 2008 23:06:38 -0800 (PST), Pentcho Valev
<pvalev@yahoo.com> wrote:

>On Jan 31, 5:20�am, Eric Baird wrote:
>> On Wed, 30 Jan 2008 01:03:23 -0800 (PST), Pentcho Valev
>> <pva...@yahoo.com> wrote <in part>:
>> >Translation from French: "Moreover, if one admits that light consists
>> >of particles, as Einstein had suggested in his first paper, 13 weeks
>> >earlier, the second principle seems absurd: a stone thrown from a fast-
>> >moving train causes much more damage than one thrown from a train at
>> >rest. Now, according to Einstein, the speed of a particle would not be
>> >independent of the state of motion of the emitting body! If we
>> >consider light as composed of particles that obey Newton's laws, those
>> >particles would conform to Newtonian relativity. In this case, it is
>> >not necessary to resort to length contration, local time and Lorentz
>> >transformations in explaining the negative result of the Michelson-
>> >Morley experiment. Einstein however, as we have seen, resisted the
>> >temptation to explain the negative result in terms of Newton's ideas,
>> >simple and familiar. He introduced his second postulate, more or less
>> >evident as one thinks in terms of waves in aether."
>>
>> >Pentcho Valev
>> >pva...@yahoo.com
>>
>> I think Einstein is supposed to have worked on emission theory himself
>> for a while, but he couldn't find a satisfactory way to reconcile the
>> idea of emission theory with the idea that lightspeed would be
>> constant for the observer as well as for the emitting body.
>>
>> Lorentz had been framing his equations in terms of wave theory, and
>> when Einstein produced his electrodynamics paper, he followed
>> Lorentz's lead.
>
>Yes. The fundamental contradiction is always between Einstein's 1905
>false light postulate (c'=c) and the true equation c'=c+v given by
>Newton's emission theory of light. Unlike his sycophants, Einstein
>fully realized the importance of this contradiction:
>
>Einstein: "If the speed of light is the least bit affected by the
>speed of the light source, then my whole theory of relativity and
>theory of gravity is false."
>
>However the fundamental contradiction often appears in different
>terms, e.g. as a contradiction between continuum and discontinuum,
>between the field concept of light and the particle concept of light
>etc. For instance, John Norton presents the fundamental contradiction
>in this way:
>
>http://philsci-archive.pitt.edu/archive/00001743/02/Norton.pdf
>John Norton: ""The principle of relativity, if implemented in Galilean
>kinematics, dictated that the modified theory must embody an emission
>theory of light. We know that Einstein entertained such a
>theory.....Einstein leveled objections against all theories of this
>type. Some were technical complications. The most fundamental,
>however, was that these EMISSION THEORIES ADMITTED NO FIELD THEORY."

Yep.

A supporting extract from "Conversations with Albert Einstein", 
R. S. Shankland, American Journal of Physics
Vol. 31 (1963), pp. 47 to 57::

:: Conversation, 4th February 1950
...
::   I mentioned the experiments which had disproved the Ritz emission 
::   theory of light [10] especially de Sitter's work on spectroscopic 
::   binaries [11] and the null result obtained by D. C. Miller [12] at 
::   Case with the modification of the Michelson-Morley experiment using 
::   sunlight. He said he knew de Sitter well but told me he considered 
::   the most decisive experiment along these lines to be the repetition 
::   of the Michelson-Morley experiment performed with starlight at 
::   Heidelberg by a student of Lenard's (Tomaschek)[13], because here, 
::   the high radial velocities involved made the null results really 
::   decisive in establishing the speed of light to be independent of the 
::   motion of the source. Here we have the true measure of Einstein the 
::   man. Lenard, who along with Stark, was the most violently Nazi of all 
::   German scientists was referred to by Einstein with complete fairness 
::   and with not the slightest trace of malice or bitterness.
::
::   This led him to a discussion of emission theories of light, and he 
::   told me that he had thought of, and abandoned the (Ritz) emission 
::   theory before 1905. He gave up this approach because he could think 
::   of no form of differential equation which could have solutions 
::   representing waves whose velocity depended on the motion of the 
::   source. In this case, the emission theory would lead to phase 
::   relations such that the propagated light would be all badly "mixed 
::   up" and might even "back up on itself." He asked me, "Do you 
::   understand that'" I said no and he carefully repeated it all. When he 
::   came again to the "mixed up" part he waved his hands before his face 
::   and laughed, all open hearty laugh at the idea!
:: 
::   Then he continued, "The theoretical possibilities in a given case are 
::   relatively few and relatively simple, and among them the choice can 
::   often be made by quite general arguments. Considering these tells us 
::   what is possible but does not tell us what reality is."
:: 
::   When I suggested that Ritz's theory was the best of the several 
::   emission theories of light, he shook his head and replied that Ritz's 
::   theory is very bad in spots. [14] But he quickly added, " Ritz made a 
::   great contribution when he showed that frequency differences are the 
::   crucial thing in spectral series." 

...

:: [10]   W. Ritz, Ann. Chem. Phys. [13] 145  (1908). 
:: [11]   W. C. de Sitter, Proc. Amsterdam Acad. [15] 1297  (1913); 
::                                     Proc. Amsterdam Acad. [16]  395  (1913). 
:: [12]   D. C. Miller, Proc. Natl. Acad. Sci. U.S. [11] 311  (1925). 
:: [13]   R. Tomaschek, Ann. Physik [73] 105  (1024). 
:: [14]   A. Einstein, Physik Z. [10] 185  (1909). 




>Einstein's 1954 confession is also an expression of the fundamental
>contradiction:
>
>http://www.perimeterinstitute.ca/pdf/files/975547d7-2d00-433a-b7e3-4a09145525ca.pdf
>John Stachel: "It is not so well known that there was "another
>Einstein," who from 1916 on was skeptical about the CONTINUUM as a
>foundational element in physics..." Einstein 1954: "I consider it
>entirely possible that PHYSICS CANNOT BE BASED UPON THE FIELD CONCEPT,
>that is on CONTINUOUS structures. Then nothing will remain of my whole
>castle in the air, including the theory of gravitation, but also
>nothing of the rest of contemporary physics."
>
>Pentcho Valev
>pvalev@yahoo.com

Another possibility is an underlying continuum that operates according
to the rules of an acoustic metric, but the "Lorentzlike" properties
of acoustic metrics that make them interesting to mathematicians doing
relativity theory didn't seem to be spotted until the 1990s. 

Acoustic metrics allow us to suggest that a photon can be emitted by a
particle at cPARTICLE , but that this velocity then only holds locally
to the particle itself. As with "phonons" in more conventional
acoustics, the presence of a signal affects the signal-carrying
properties of the medium. In this case, the "signal" is the moving
body, and the related distortions of the lightbeam metric between two
moving bodies act as a regulating mechanism for the velocity of
lightsignals passed between them.

So an acoustic metric would seem to give you the "emission theory"
properties that you like, while also being compatible with wave
theory. It combines particulate behaviour with a geometrical approach,
by describing the presence and velocity of particles as moving,
distorted dents or kinks in the background lightbeam geometry. 

It's actually pretty cool. It even seems to be QM-compatible.



The big problem with acoustic metrics is "political", because an
acoustic metric seems to not only to destroy the definitional and
derivational basis of special relativity, it also seems to suggest
that SR's fundamental equations of motion may be wrong. The SR-style
"flat-spacetime" approach doesn't work with acoustic metrics, because
an observer or observed object //doesn't exist// unless there is a
matching deviation from flat spacetime in the metric, and these AM
distortions get more severe as relative velocities between bodies
approach the speed of light.  

So if we take acoustic metrics seriously, we seem to have to set
special relativity to one side and rederive our equations of motion
from scratch, in a way that's compatible with the new
velocity-dependent lightbeam geometry. 

I've not seen anybody else attempt this derivation, but from my own
little explorations, it seems that 

     (a) The new relationships can't be those of SR, which are too 
      perfectly locked to the condition of flat spacetime. 

     (b) The new relationships would seem to have to be //redder// 
      than SR's predictions, which isn't a possibility that's usually 
      taken seriously when we test SR. When our experiments report 
      results are //too// red (which they often do), we usually blame 
      this on things like detector misalignment or mirror recoil. 
 
     (c) There is one particular solution that stands out from all the
others, which turns out to be "redder and shorter" than the 
      SR solution by an additional Lorentz factor. This solution seems
to be required for compatibility with Hawking radiation.

But, rather embarrassingly, this new set of "preferred candidate"
equations for the momentum and energy of light leaving a moving object
in an acoustic metric turns out to be the same set of relationships
that we'd get by not knowing anything about C20th physics and just
applying old-fashioned Newtonian ballistic emission theory. 

Ouch.

Interesting times.

-------
"Acoustic metric" on Wikipedia:
http://en.wikipedia.org/wiki/Acoustic_metric 

Review article by Carlos Barcelo, Stefano Liberati and Matt Visser on
"analogue gravity" (the use of acoustic metrics to model non-GR1915
effects such as Hawking radiation) 
http://xxx.lanl.gov/abs/gr-qc/0505065


=Erk= (Eric Baird)
 http://books.google.com/books?q=0955706807&btnG=Search+Books