Albert Einstein Institute: "In the above paragraphs, we have only considered moving sources. In fact, a closer look at cases where it is the receiver that is in motion will show that this kind of motion leads to a very similar kind of Doppler effect.
Here is an animation of the receiver moving towards the source:

https://www.einstein-online.info/wp-content/uploads/SRT_Dopplereffekt_Pulse_4_%C2%A9_Daniela_Leitner_Markus_Poessel_Einstein-Online.gif

By observing the two indicator lights, you can see for yourself that, once more, there is a blue-shift - the pulse frequency measured at the receiver is somewhat higher than the frequency with which the pulses are sent out. This time, the distances
between subsequent pulses are not affected, but still there is a frequency shift: As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the
source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." http://www.einstein-online.info/spotlights/doppler.html

The speed of the light pulses as measured by the source is c = 3d/t, where d is the distance between the pulses and t is "the time it takes the source to emit three pulses".

The speed of the pulses as measured by the moving receiver is c' = 4d/t > c, in violation of Einstein's relativity.

See more here: https://twitter.com/pentcho_valev

Pentcho Valev

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Einstein wrestled with his conscience "over a lengthy period of time, to the point of despair" before introducing the constant-speed-of-light nonsense:

John Stachel: "But this seems to be nonsense. How can it happen that the speed of light relative to an observer cannot be increased or decreased if that observer moves towards or away from a light beam? Einstein states that he wrestled with this problem
over a lengthy period of time, to the point of despair." http://www.aip.org/history/exhibits/einstein/essay-einstein-relativity.htm

The nonsense proved highly malignant - it gradually permeated the whole of physics and killed this branch of science (converted it into an insane ideology):

"He opened by explaining how Einstein's theory of relativity is the foundation of every other theory in modern physics and that the assumption that the speed of light is constant is the foundation of that theory. Thus a constant speed of light is
embedded in all of modern physics and to propose a varying speed of light (VSL) is worse than swearing! It is like proposing a language without vowels." http://www.thegreatdebate.org.uk/VSLRevPrnt.html

John Stachel's "seems to be nonsense" is a euphemism. The constancy of the speed of light is OBVIOUS NONSENSE:

https://www.youtube.com/watch?v=bg7O4rtlwEE

The speed of the light pulses as measured by the stationary observer is

c = df

where d is the distance between the pulses and f is the frequency measured by the stationary observer. The speed of the pulses as measured by the moving observer is

c'= df' > c

where f' > f is the frequency measured by the moving observer.

More here: https://twitter.com/pentcho_valev

Pentcho Valev

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 30.01.2021 17:56, Pentcho Valev wrote:

Albert Einstein Institute: "In the above paragraphs, we have only considered moving sources. In fact, a closer look at cases where it is the receiver that is in motion will show that this kind of motion leads to a very similar kind of Doppler effect.

Here is an animation of the receiver moving towards the source:

https://www.einstein-online.info/wp-content/uploads/SRT_Dopplereffekt_Pulse_4_%C2%A9_Daniela_Leitner_Markus_Poessel_Einstein-Online.gif

By observing the two indicator lights, you can see for yourself that, once more, there is a blue-shift - the pulse frequency measured at the receiver is somewhat higher than the frequency with which the pulses are sent out. This time, the distances

between subsequent pulses are not affected, but still there is a frequency shift: As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the
source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." http://www.einstein-online.info/spotlights/doppler.html

The speed of the light pulses as measured by the source is c = 3d/t, where d is the distance between the pulses and t is "the time it takes the source to emit three pulses".

The speed of the pulses as measured by the moving receiver is c' = 4d/t > c, in violation of Einstein's relativity.

See more here: https://twitter.com/pentcho_valev

Pentcho Valev

There is something very basic what you seemingly have not understood so
far. The Doppler effect is additional to relativistic effects. It is the dominant effect at low speeds of course in case that the source is
approaching or leaving the target. Do not mismatch the effects. I
recommend to read a book about relativity and make the exercises. Then
read about Doppler effects and make the exercises. Then combine both
effects. Then talk and write about it.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Il 08/02/2021 23:41, AndreK ha scritto:

There is something very basic what you seemingly have not understood so
far. The Doppler effect is additional to relativistic effects. It is the dominant effect at low speeds of course in case that the source is approaching or leaving the target. Do not mismatch the effects. I
recommend to read a book about relativity and make the exercises. Then
read about Doppler effects and make the exercises. Then combine both
effects. Then talk and write about it.

Are you really trying to convince Pentcho that Relativity Theory is right? Mission impossible...

Luigi Caselli

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 10.02.2021 17:15, Luigi Caselli wrote:

Il 08/02/2021 23:41, AndreK ha scritto:

There is something very basic what you seemingly have not understood
so far. The Doppler effect is additional to relativistic effects. It
is the dominant effect at low speeds of course in case that the source
is approaching or leaving the target. Do not mismatch the effects. I
recommend to read a book about relativity and make the exercises. Then
read about Doppler effects and make the exercises. Then combine both
effects. Then talk and write about it.

Are you really trying to convince Pentcho that Relativity Theory is right? Mission impossible...

Luigi Caselli

You are right, thank you for the hint. I have just read ABOUT that guy.
It sounds like a bot, some AI text generators from the seventies.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Den 08.02.2021 23:41, skrev AndreK:

On 30.01.2021 17:56, Pentcho Valev wrote:

By observing the two indicator lights, you can see for yourself that,
once more, there is a blue-shift - the pulse frequency measured at the
receiver is somewhat higher than the frequency with which the pulses
are sent out. This time, the distances between subsequent pulses are
not affected, but still there is a frequency shift

There is something very basic what you seemingly have not understood so
far. The Doppler effect is additional to relativistic effects. It is the dominant effect at low speeds of course in case that the source is approaching or leaving the target. Do not mismatch the effects. I
recommend to read a book about relativity and make the exercises. Then
read about Doppler effects and make the exercises. Then combine both
effects. Then talk and write about it.

I see you now know about Pentcho Valev. :-)

But there is an interesting point in what he says.

According to the Galilean transformation, frequency
is Doppler shifted, wavelength is not.
And this will with extremely good approximation
be valid for sound.

But what about light?

It is an empirical fact that the Doppler shift of frequency
and wavelength always are the inverse of each other.
(Pentcho Valev doesn't know this, and there is no point in telling him.)

We know that for any wave, we have per definition:
f*lambda = w,
where w is the speed of the wave relative to
the inertial frame of reference were the frequency
is f and the wavelength is lambda.
Let's call this inertial frame K.

Let the inertial frame K' be moving at some speed relative to K.

In K:
f*lambda = w

In K':
f' = f*D
lambda' = lambda/D

f'*lambda' = f*D*lambda/D = f*lambda = w

Conclusion:
The empirical fact that the Doppler shift of frequency and
wavelength always are the inverse of each other proves that
the speed of light is invariant (in vacuum).

It doesn't say what the invariant value is, of course,
but we know that it is c.

And the only transform that predicts that the Doppler shift
of frequency and wavelength are the inverse of each other
is the Lorentz transform.

--
Paul

https://paulba.no/

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Monday, February 22, 2021 at 12:51:37 PM UTC+1, Paul B. Andersen wrote:

It is an empirical fact that the Doppler shift of frequency
and wavelength always are the inverse of each other.

Don't lie so blatantly, Andersen:

"Thus, the moving observer sees a wave possessing the same wavelength [...] but a different frequency [...] to that seen by the stationary observer." http://farside.ph.utexas.edu/teaching/315/Waveshtml/node41.html

"Vo is the velocity of an observer moving towards the source. This velocity is independent of the motion of the source. Hence, the velocity of waves relative to the observer is c + Vo. [...] The motion of an observer does not alter the wavelength. The
increase in frequency is a result of the observer encountering more wavelengths in a given time." http://a-levelphysicstutor.com/wav-doppler.php

Albert Einstein Institute: "In the above paragraphs, we have only considered moving sources. In fact, a closer look at cases where it is the receiver that is in motion will show that this kind of motion leads to a very similar kind of Doppler effect.
Here is an animation of the receiver moving towards the source:

https://www.einstein-online.info/wp-content/uploads/SRT_Dopplereffekt_Pulse_4_%C2%A9_Daniela_Leitner_Markus_Poessel_Einstein-Online.gif

By observing the two indicator lights, you can see for yourself that, once more, there is a blue-shift - the pulse frequency measured at the receiver is somewhat higher than the frequency with which the pulses are sent out. This time, the DISTANCES
BETWEEN SUBSEQUENT PULSES ARE NOT AFFECTED, BUT STILL THERE IS A FREQUENCY SHIFT: As the receiver moves towards each pulse, the time until pulse and receiver meet up is shortened. In this particular animation, which has the receiver moving towards the
source at one third the speed of the pulses themselves, four pulses are received in the time it takes the source to emit three pulses." http://www.einstein-online.info/spotlights/doppler.html

Pentcho Valev

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)