🚀 go-pugleaf

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. 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 -