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Re: The incoming speed of light is variable

Cross-posted to 2 groups.

Followups directed to: sci.physics.relativity

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The ’nym-shifting troll trolled as "Micah Strobl" <aui@cwwi.cu>:

> Gary Harnagel wrote:
>>> > This was refuted by the Michelson-Morley experiment and many
>>> > subsequent ones.  Can you explain why you are 130 years out of date?
>>> No way, the MMX is not capable of detecting the incoming speed of light
>>> if the light source is moving wrt the apparatus.
>> The speed of light is invariant, stupid ignoramus; so yes, the MMX
>> doesn't detect the speed of light: it detects wavelength shift.
> 
> You contradict yourself.

That depends on what he means by “wavelength shift”; if he means that the 
wavelength of the light should change, then that is wrong.  c = λ f, so from 
λ changing cannot be concluded that c is changing; in fact, the Doppler 
effect (well know at the time) would *require* that f is changing inversely 
to λ, keeping c constant.

> Why should that happen, to shift.

The MMX was designed to detect _phase_ shift instead, as one portion of the 
light would arrive sooner that the other; but it did not detect any.  
Neither did refined repetitions of it, to this day.

However, the Michelson interferometer is a useful instrument to make other 
important observations on smallest lengths (that earned Michelson the Nobel 
Prize in Physics for the invention); currently, that design allows us to 
detect gravitational waves directly (because the speed of light remains 
constant, but the length of the arms of the interferometer does not when a 
gravitational wave passes through the instrument, confirming GR again).

> Once you say it's invariant, aka it does NOT vary.

The *speed* of light is (Lorentz-)invariant, and by observing *no* *phase* 
shift, the possibility that there was a static, absolutely stationary medium 
(the luminiferous ether) to change that was eventually excluded.  However, 
if light source and observer move relative to each other, the *observed* 
*frequency* and *observed* *wavelength* change compared to the stationary 
case.

(*PLONK*)


PointedEars
-- 
Q: What did the nuclear physicist post on the laboratory door
   when he went camping?  
A: 'Gone fission'.
(from: WolframAlpha)

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Re: The incoming speed of light is variable Micah Strobl <aui@cwwi.cu> - 2018-03-27 18:11 +0000
  Re: The incoming speed of light is variable Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-27 20:53 +0200

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