Groups > sci.physics.relativity > #402940

Re: Why Do SR and BaTh Both Give the Right Answer for a Sagnac Ring Gyro?

From	HGW <hw@....>
Newsgroups	sci.physics.relativity
Subject	Re: Why Do SR and BaTh Both Give the Right Answer for a Sagnac Ring Gyro?
Date	2016-12-25 08:39 +1100
Organization	Aioe.org NNTP Server
Message-ID	<o3mpva$tu5$1@gioia.aioe.org> (permalink)
References	<o3la2k$kut$1@gioia.aioe.org> <4ead48f7-f281-4cdb-bc02-12316f993bab@googlegroups.com>

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On 24/12/16 20:40, Prokaryotic Caspase Homolog wrote:
> (forgot to include link to diagram in deleted post)
>
> On Saturday, December 24, 2016 at 2:02:32 AM UTC-6, HGW wrote:
>> When viewed in the inertial frame, both SR and BaTh agree that the two
>> beams of a ring gyro travel different distances. SR says both beams move
>> at c in the non-rotating frame and have different travel times, Bath
>> says the travel times are the same. SR says light is a simple oscillator
>> and since both rays leave together, they must reunite with different
>> phase. BaTh says light does not oscillate during travel but has a fixed
>> wavelength.
>>
>> SR says the travel times are 2piR/(c+v) and 2piR/(c-v) and the
>> difference is = 2piR(2v/(c^2-v^2)) = 4Aw /c^2.
>> Therefore phase difference at receiver is = 4Aw/(c.Lambda)
>>
>> BaTh says both travel times are: t = 2piR/c and the path lengths are
>> (c+v)t and (c-v)t. Therefore the difference in path lengths is 4piRv/c.
>> Since lambda is constant, the phase difference = 4Aw/(c.lambda) as before.
>>
>> So how can two diametrically opposed theories produce the same correct
>> answer?
>
> This is because the version of BaTh that you use in your ring gyro analysis is
> not the same version that you use in your variable star analysis. If you analyze
> your "rayphases" program output carefully, you will see that it actually assumes
> the existence of an absolute frame. Your oppositely traveling rays originate
> from a fixed point in absolute space, and as the ring rotates, the distance of
> an observer from this fixed point continuously increases or decreases. The
> observer thus counts differing numbers of waves arriving from the CW or CCW
> direction.
>
>     *** THIS MECHANISM DOES NOT DEPEND ON ROTATION ***

The BaTh analysis certainly does not assume absolute space. It DOES 
assume the well known truism that rotation is absolute and it is 
therefore perfectly legitimate to do the analysis from the POV of the 
non-rotating frame. The only assumption BaTh makes is that both rays 
leave the source at c, which is obviously true. Nothing else can 
influence their speeds so they have no other reference.


> You can straighten out the ring and observe exactly the same thing.

...and you can get it all wrong....

> In the
> following diagram, I have straightened out a fiber optic gyroscope and mounted
> a straight section onto a board which I set swinging back and forth. A laser
> feeds light into the mounted section from both ends. The rays meet in the
> middle at a phase detector. Because of the absolute space that you unwittingly
> postulate, BaTh predicts that the central phase detector will detect fringe
> shift as the board swings back and forth.
> https://drive.google.com/open?id=0B8XIf0XcrpOcN3kzQ0huZDdvUms

It is nonsense. In the non-rotating frame, the two rays have different 
path lengths. That has nothing to do with any 'absolute space' and if 
you straighten it out, that what you have to draw.
On the other hand, Einstein's explanation clearly requires absolutism to 
cause the two rays to move at different speeds relative to the common 
source.






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