🚀 go-pugleaf

On Jun 20, 8:41 am, "kens...@erinet.com" <kens...@erinet.com> wrote:
> On Jun 20, 1:22 am, Pentcho Valev <pva...@yahoo.com> wrote:
>
>
>
> > On Jun 18, 9:13 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote in
> > sci.physics.relativity:
>
> > > Henry Wilson, DSc wrote:
> > > > How can all the starlight in the universe
> > > > that is moving in our direction magically find a common speed if there is no
> > > > 'medium' in space that determines that speed?
>
> > > The same way that a straight line "magically finds" the shortest
> > > distance between two spatial points (over distances less than ~1000 km).
> > > That is, GEOMETRY.
>
> > > I don't know why the space-time geometry of the world we inhabit has
> > > this property, but experiments show that this model is one of the best
> > > and most widely-applicable descriptions of our world that have ever been
> > > discovered.
>
> > > This is not really a surprising result, to people who have actually
> > > studied the matter. Here's a simple explanation:
>
> > > Assume the world we inhabit is causal. That is, for a given point in
> > > space P and given time T, all phenomena located at P at time T can
> > > depend only on phenomena near P a short time before T. This implies that
> > > it is not possible for some object or influence to "zoom in from
> > > infinity" with infinite speed and affect any phenomena located at P at
> > > time T [#]. So there must be a finite upper bound on the speed of all
> > > objects and influences -- that's the only way to ensure they are near P
> > > a short time before T. Mathematically this implies that the only valid
> > > transformation group among inertial frames is the Poincaré group [@],
> > > which has the property that all objects and signals are restricted to
> > > speeds less than a universal maximum speed; experiments show that this
> > > universal speed limit is equal to the vacuum speed of light. The theory
> > > that describes this is known as Special Relativity, and experimentally
> > > it has been observed to be valid for all phenomena that have been tested
> > > under conditions where gravity can be ignored.
>
> > Experimental results should be interpreted, Honest Roberts. The
> > Doppler effect (shift in frequency) is unquestionable but it takes a
> > sane (non-Einsteinian) mind to say whether it is due to shift in
> > wavength (then no problem for Einstein's 1905 light postulate) or
> > shift in the speed of light (then Einstein's 1905 light postulate is
> > false). Consider a light source and an observer initially at rest
> > relative to each other. Then the observer suddenly starts moving, with
> > constant speed, towards the light source. The frequency unquestionably
> > shifts, but can you imagine the wavelength shifting as well?
>
> No there is no wavelength shift.

DIRECT measurement of the wavelength says otherwise. Do you know how
to directly measure the wavelength of light, Ken?

> The wavelength of an elementary
> source such as sodium is a universal constant of 589 nm. That means
> that all observer measures his sodium source to have a wavelength of
> 589 nm.
>
> >A sane
> > (non-Einsteinian) mind cannot imagine any shift in wavelength (the
> > wavelength can only be determined by the source and has nothing to do
> > with the movements of the observer) and concludes that the speed of
> > light has shifted, in accordance with the formula:
>
> > frequency = (speed of light)/(wavelength)
>
> Yes the speed of incoming sodium light is as follows:
> c' = (measured incoming frequency)(universal wavelength of sodium 589
> nm)
>
> Ken Seto
>
>
>
> > Pentcho Valev
> > pva...@yahoo.com- Hide quoted text -
>
> > - Show quoted text -
>
>