On August 2, Prokaryotic Capase Homolog wrote:
>>>>> https://commons.wikimedia.org/wiki/File:De_Sitter_argument_against_emission_theory.gif
>
>>>> "According to simple emission theory, light thrown off by an object should move
>>>> at a speed of c with respect to the emitting object."
>>>> er, isn't that Einstein's second postulate?
>
>>> No.
>
> Of course light is emitted at c relative to the emitter.

ur confused. Again.

Let's continue the reading lesson, from the text quoted above:
"According to simple emission theory, light thrown off by an object should move
at a speed of c with respect to the emitting object."

Continuing from your cite:
"Willem de Sitter argued that if this were true, ..."

What does this conditional clause imply? It means, in normal English,
that de Sitter disbelieved this conditional, and wished to demonstrate
its falseness. I doubt that was his intent. In fact, it's preposterous -
IT'S EINSTEIN'S SECOND POSTULATE. Which you concede, in your grumpy manner..

Writing is the clearest indication of one's thoughts. Yours are a jumble.

PS The .gif is nice. However, why do the pulses change color along
the route? Does not compute.

PSS The animation also presents a cool optical illusion. Not physics,
but a human vision quirk.

PSSS The spectral shift arguments are weak. Doppler reasoning assumes
constant c. If light speed is actually c + kv, the receiver sees a 'variable
Doppler'. It results from two degrees of freedom - k and v - both unknown,
and unsolvable. That is, the spectral shifts might or might not be due
to k ≠ 0
PSSSS The spectral shift arguments are even weaker, as spectrometers
use diffraction gratings, which assume a known light speed, then
calculate frequency... from assumed light speed!

Much circularity in de Sitter's arguments. Better is to apply Occam's
razor, and say that special relativity is the simplest model.

--
Rich

On Friday, August 4, 2023 at 6:23:49 PM UTC-5, RichD wrote:
> On August 2, Prokaryotic Capase Homolog wrote:
> >>>>> https://commons.wikimedia.org/wiki/File:De_Sitter_argument_against_emission_theory.gif
> >
> >>>> "According to simple emission theory, light thrown off by an object should move
> >>>> at a speed of c with respect to the emitting object."
> >>>> er, isn't that Einstein's second postulate?
> >
> >>> No.
> >
> > Of course light is emitted at c relative to the emitter.
>
> ur confused. Again.
>
> Let's continue the reading lesson, from the text quoted above:
> "According to simple emission theory, light thrown off by an object should move
> at a speed of c with respect to the emitting object."
>
> Continuing from your cite:
> "Willem de Sitter argued that if this were true, ..."
>
> What does this conditional clause imply? It means, in normal English,
> that de Sitter disbelieved this conditional, and wished to demonstrate
> its falseness. I doubt that was his intent. In fact, it's preposterous -
> IT'S EINSTEIN'S SECOND POSTULATE.

No, it isn't.

It is a simple consequence of the second postulate,
but it is not the second postulate.

> Which you concede, in your grumpy manner.
>
> Writing is the clearest indication of one's thoughts. Yours are a jumble.
>
> PS The .gif is nice. However, why do the pulses change color along
> the route? Does not compute.

Compression of waves results in a higher frequency.

Emission theory predicts profound color and intensity changes.

See also Paul Andersen's PDF for a more quantitative treatment.
> PSS The animation also presents a cool optical illusion. Not physics,
> but a human vision quirk.
>
> PSSS The spectral shift arguments are weak. Doppler reasoning assumes
> constant c. If light speed is actually c + kv, the receiver sees a 'variable
> Doppler'. It results from two degrees of freedom - k and v - both unknown,
> and unsolvable. That is, the spectral shifts might or might not be due
> to k ≠ 0
>
> PSSSS The spectral shift arguments are even weaker, as spectrometers
> use diffraction gratings, which assume a known light speed, then
> calculate frequency... from assumed light speed!

They measure wavelength, regardless of light speed.
> Much circularity in de Sitter's arguments.

Not circular at all.

> Better is to apply Occam's
> razor, and say that special relativity is the simplest model.

Of course it is.