Re: SR length contraction - the train example reworked.

On Sep 21, 7:55 am, Mathal <mathmusi...@xxxxxxxxx> wrote:
On Sep 20, 8:32 pm, "Inertial" <relativ...@xxxxxxxx> wrote:





"Mathal" <mathmusi...@xxxxxxxxx> wrote in message

news:0b0702ac-587a-40da-970b-e22b2461b7b2@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Sep 20, 5:44 pm, "Inertial" <relativ...@xxxxxxxx> wrote:
"Mathal" <mathmusi...@xxxxxxxxx> wrote in message

news:7bc8824f-7198-4017-bd45-675e5d980ee3@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

The observer on the embankment measuring the distance travelled by
the
light and dividing this distance by the time the light took to
travel
this distance comes up with the speed of light.

No more than a shadow seen racing across the surface of the
moon has any relevance to the speed of light.

On the train time is
running slower than in the embankment rest frame.

Not to a physicist.

The distance the
light travels WRT the frame the light is measured in is less than
the
distance measured in the rest frame. There is no space contraction
in
the path of the light WRT the frame on the train. There is
contraction
WRT the path of the train but in the example this is irrelevant.. The
measurement of the distance by the time on the train will again be
the
speed of light.

Ahhh.... No.

  The one and only thing two frames of reference with different
velocities can agree upon is the speed of light.

And the laws of physics .. some people may think that is important ;);)

I believe we are in accord. I used different terminology but what you
said mirrors what I meant.

Yeup .. I'm not arguing with you .. just poitning out that there is more
than just speed of light they agree on.  If you meant the only VELOCITIES
they can agree on is the speed of light, then that's ok.

  Speaking of laws of physics Conservation of Momentum  and
Conservation of Energy only hold when  photons going from one frame to
another are remapped with the appropriate Lorenz tranfers for the
wavelength/frequency.

Eh?  How do you remap a photon?

Consider photons coming from a red-shifted galaxy. In the red-shifted
galaxy's frame of reference the photons are emited  with  the
recognized patterns of frequencies associated with hydrogen, helium
and to a lesser extent the other atoms that make up the matter in the
galaxy. In our frame of reference these same photons are measured as
red-shifted from where we know they are in our galaxy. From this we
can extrapolate the relative velocity of the red-shifted galaxy
compared to us. Conversely blue-shifted galaxies such as Andromeda we
know are approaching us with a velocity we 'get' from the shift in the
wavelength of the galaxy's spectrum.
   A photon is a quanta of energy. This may seem fanciful but this is
how I 'see' how things work. An electron, in it's frame of reference,
is at 'rest'. When a photon is absorbed or emited the electron
achieves a new state of rest. To paraphrase Virginia Wolfe a quanta is
a quanta is a quanta from the electron's frame. From an 'external'
point of view it is a particular wavelength which is dependant on the
frame the photon is measured from. The red-shifted galaxy 'thinks'
it's sending a particular spectrum array of frequencies of light and
we 'think' we are receiving a particular array of frequencies and
using our instruments that is what we both measure. The amount of
energy depends on who is measuring the photon, the wavelength of the
photon depends on who measures the photon.

  If a faster frame received a photon of the same wavelength/
frequency as the slower frame, in the new frame the photon would
impart more momentum/energy than it has to impart.

What new frame .. which photon is imparting what?  Your sentence is a trifle
confusing.

What I was doing was disproving the alternative that all frames
measure the same wavelength of a particular stream of photons. Yes the
wording was nebulous. I hope this clarifies what I meant.
   Mathal

Still nebulous. When a slower frame sends a photon of a particular
frequency to a faster moving frame WRT it, the wavelength of the
photon measured in the faster receiving frame will necessarily be
longer.
Mathal
.

Relevant Pages

  • Re: SR length contraction - the train example reworked.
    ... this distance comes up with the speed of light. ... running slower than in the embankment rest frame. ... WRT the path of the train but in the example this is irrelevant. ... measurement of the distance by the time on the train will again be the ...
    (sci.physics.relativity)
  • Re: SR length contraction - the train example reworked.
    ... this distance comes up with the speed of light. ... running slower than in the embankment rest frame. ... units of measurement - length and time, fiddled so that it be so. ... requires that not only can two identical clocks have ticks of different ...
    (sci.physics.relativity)
  • Re: SR length contraction - the train example reworked.
    ... this distance comes up with the speed of light. ... running slower than in the embankment rest frame. ... units of measurement - length and time, fiddled so that it be so. ... slower that another identical clock - which is physically absurd. ...
    (sci.physics.relativity)
  • Re: Experimental disproof of the theory of Relativity
    ... Attempts to define a "photon frame" lead to logical ... any physics concerned with measurement and prediction of measurement. ... provided the distance between A and B is less than 10 lightseconds. ...
    (sci.physics.relativity)
  • Re: Bending of light not well authenticated
    ... > Proper spacetime implies proper time of a local observer. ... > non-accelerated frame, the speed of light is always c. ... When you receive or observe a photon directly, ... After integrating the angle to get the angle of deflection, ...
    (sci.physics.relativity)