"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." https://history.aip.org/exhibits/einstein/essay-einstein-relativity.htm

Brian Greene: "Whether you run toward or away from a beam of light, its speed will be unchanged when you measure it...That's kind of crazy! How could a speed behave that way when it comes to the speed of light? And the answer is that space and time do not behave as we would think, based on everyday experience." https://www.youtube.com/watch?v=-Irlq3TFr8Q

Brian Greene: "If space and time did not behave this way, the speed of light would not be constant and would depend on the observer's state of motion. But it is constant; space and time do behave this way. Space and time adjust themselves in an exactly compensating manner so that observations of light's speed yield the same result, regardless of the observer's velocity." http://www.pbs.org/wgbh/nova/physics/special-relativity-nutshell.html

For the sake of argument, I assume that "space and time do behave this way".. Does this make the constancy of the speed of light plausible? No. An Achilles' heel remains.

An observer starts moving towards the light source, and the frequency at him shifts:

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

In accordance with the formula

(frequency) = (speed of light)/(wavelength),

either

(A) there is a shift in speed of light relative to the observer, proportional to the frequency shift,

or

(B) there is a shift in wavelength inversely proportional to the frequency shift.

The alternative (B) is obviously absurd so the speed of light remains variable, no matter how space and time are vandalized:

"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

Max Planck Institute for Gravitational Physics: "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." https://www.einstein-online.info/en/spotlight/doppler/

"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

"The Doppler effect is the shift in frequency of a wave that occurs when the wave source, or the detector of the wave, is moving. Applications of the Doppler effect range from medical tests using ultrasound to radar detectors and astronomy (with electromagnetic waves)...Moving Observer. Let's say you, the observer, now move toward the source with velocity Vo. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: V' = V+Vo. The frequency of the waves you detect is higher, and is given by: f' = V'/λ = (V+Vo)/λ." http://physics.bu.edu/~redner/211-sp06/class19/class19_doppler.html

"The wavelength is staying the same in this [moving observer] case." https://www.youtube.com/watch?v=MHepfIIsKcE

Pentcho Valev https://twitter.com/pentcho_valev

oh shut the f* up, Pentcho !

On Wednesday, May 10, 2023 at 3:09:48 PM UTC-7, Pentcho Valev wrote:
> "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." https://history.aip.org/exhibits/einstein/essay-einstein-relativity.htm
>
> Brian Greene: "Whether you run toward or away from a beam of light, its speed will be unchanged when you measure it...That's kind of crazy! How could a speed behave that way when it comes to the speed of light? And the answer is that space and time do not behave as we would think, based on everyday experience." https://www.youtube.com/watch?v=-Irlq3TFr8Q
>
> Brian Greene: "If space and time did not behave this way, the speed of light would not be constant and would depend on the observer's state of motion. But it is constant; space and time do behave this way. Space and time adjust themselves in an exactly compensating manner so that observations of light's speed yield the same result, regardless of the observer's velocity." http://www.pbs.org/wgbh/nova/physics/special-relativity-nutshell.html
>
> For the sake of argument, I assume that "space and time do behave this way". Does this make the constancy of the speed of light plausible? No. An Achilles' heel remains.
>
> An observer starts moving towards the light source, and the frequency at him shifts:
>
> https://youtube.com/watch?v=bg7O4rtlwEE
>
> In accordance with the formula
>
> (frequency) = (speed of light)/(wavelength),
>
> either
>
> (A) there is a shift in speed of light relative to the observer, proportional to the frequency shift,
>
> or
>
> (B) there is a shift in wavelength inversely proportional to the frequency shift.
>
> The alternative (B) is obviously absurd so the speed of light remains variable, no matter how space and time are vandalized:
>
> "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
>
> Max Planck Institute for Gravitational Physics: "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." https://www.einstein-online.info/en/spotlight/doppler/
>
> "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
>
> "The Doppler effect is the shift in frequency of a wave that occurs when the wave source, or the detector of the wave, is moving. Applications of the Doppler effect range from medical tests using ultrasound to radar detectors and astronomy (with electromagnetic waves)...Moving Observer. Let's say you, the observer, now move toward the source with velocity Vo. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: V' = V+Vo. The frequency of the waves you detect is higher, and is given by: f' = V'/λ = (V+Vo)/λ." http://physics.bu.edu/~redner/211-sp06/class19/class19_doppler.html
>
> "The wavelength is staying the same in this [moving observer] case." https://www.youtube.com/watch?v=MHepfIIsKcE
>
> Pentcho Valev https://twitter.com/pentcho_valev
Thank you Mr. Valev for the data. It is wonderful how some people can deny relative velocity for light when all velocity is additive velocity. All the SRT formulas are mathematical chicanery as much as a business's cooked books are. The numbers all work out to balanced books because they have been manipulated deceitfully. They are designed to negate relative velocity instead of incorporating it into the Maxwell equations.

On 2023-05-10 22:15:31 +0000, Python said:

> oh shut the f* up, Pentcho !

Too late for that, I fear. He's been at it for at least 25 years and
he's not going to stop now. He's even picked up a fan or two.

--
athel -- biochemist, not a physicist, but detector of crackpots

"Special relativity is based on the observation that the speed of light is always the same, independently of who measures it, or how fast the source of the light is moving with respect to the observer. Einstein demonstrated that as an immediate consequence, space and time can no longer be independent, but should rather be considered a new joint entity called "spacetime." https://www.bowdoin.edu/news/2015/04/physics-professor-baumgarte-describes-100-years-of-gravity.html

So if spacetime is "doomed", the underlying premise, Einstein's 1905 constant-speed-of-light postulate, is doomed as well, no? Not in Einstein's schizophrenic world. Theoretical physicists repudiate spacetime but worship the constancy of the speed of light:

Nima Arkani-Hamed: "Almost all of us believe that spacetime doesn't really exist, spacetime is doomed and has to be replaced." https://youtu.be/U47kyV4TMnE?t=369

"We've known for decades that space-time is doomed," says Arkani-Hamed. "We know it is not there in the next version of physics." https://www.discovermagazine.com/the-sciences/amplituhedron-may-shape-the-future-of-physics

"Einstein introduced a new notion of time, more radical than even he at first realized. In fact, the view of time that Einstein adopted was first articulated by his onetime math teacher in a famous lecture delivered one century ago. That lecture, by the German mathematician Hermann Minkowski, established a new arena for the presentation of physics, a new vision of the nature of reality redefining the mathematics of existence. The lecture was titled Space and Time, and it introduced to the world the marriage of the two, now known as spacetime. It was a good marriage, but lately physicists passion for spacetime has begun to diminish. And some are starting to whisper about possible grounds for divorce." https://www.sciencenews.org/article/its-likely-times-are-changing

"Was Einstein wrong? Do we have to kill off the theory of space and time to make sense of the universe?" https://space.com/end-of-einstein-space-time

"Bye bye space-time: is it time to free physics from Einstein's legacy?" https://www.newscientist.com/article/mg24332472-900-bye-bye-space-time-is-it-time-to-free-physics-from-einsteins-legacy/

Philip Ball: "And by making the clock's tick relative - what happens simultaneously for one observer might seem sequential to another - Einstein's theory of special relativity not only destroyed any notion of absolute time but made time equivalent to a dimension in space: the future is already out there waiting for us; we just can't see it until we get there. This view is a logical and metaphysical dead end, says [Lee] Smolin." http://www.guardian.co.uk/books/2013/jun/10/time-reborn-farewell-reality-review

"Was Einstein wrong? At least in his understanding of time, [Lee] Smolin argues, the great theorist of relativity was dead wrong. What is worse, by firmly enshrining his error in scientific orthodoxy, Einstein trapped his successors in insoluble dilemmas." http://leesmolin.com/time-reborn-2/reviews/

"Rethinking Einstein: The end of space-time...Horava, who is at the University of California, Berkeley, wants to rip this fabric apart and set time and space free from one another..." https://www.newscientist.com/article/mg20727721-200-rethinking-einstein-the-end-of-space-time/

What scientific idea is ready for retirement? Steve Giddings: "Spacetime. Physics has always been regarded as playing out on an underlying stage of space and time. Special relativity joined these into spacetime...The apparent need to retire classical spacetime as a fundamental concept is profound..." https://www.edge.org/response-detail/25477

"...says John Norton, a philosopher based at the University of Pittsburgh, Pennsylvania. Norton is hesitant to express it, but his instinct - and the consensus in physics - seems to be that space and time exist on their own. The trouble with this idea, though, is that it doesn't sit well with relativity, which describes space-time as a malleable fabric whose geometry can be changed by the gravity of stars, planets and matter." https://www.newscientist.com/article/mg20026831.500-what-makes-the-universe-tick

Nobel Laureate David Gross observed, "Everyone in string theory is convinced...that spacetime is doomed. But we don't know what it's replaced by." https://www.edge.org/response-detail/26563

Pentcho Valev https://twitter.com/pentcho_valev

On Thursday, May 11, 2023 at 3:09:48 AM UTC+5, Pentcho Valev wrote:
> "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." https://history.aip.org/exhibits/einstein/essay-einstein-relativity.htm
>
> Brian Greene: "Whether you run toward or away from a beam of light, its speed will be unchanged when you measure it...That's kind of crazy! How could a speed behave that way when it comes to the speed of light? And the answer is that space and time do not behave as we would think, based on everyday experience." https://www.youtube.com/watch?v=-Irlq3TFr8Q
>
> Brian Greene: "If space and time did not behave this way, the speed of light would not be constant and would depend on the observer's state of motion. But it is constant; space and time do behave this way. Space and time adjust themselves in an exactly compensating manner so that observations of light's speed yield the same result, regardless of the observer's velocity." http://www.pbs.org/wgbh/nova/physics/special-relativity-nutshell.html
>
> For the sake of argument, I assume that "space and time do behave this way". Does this make the constancy of the speed of light plausible? No. An Achilles' heel remains.
>
> An observer starts moving towards the light source, and the frequency at him shifts:
>
> https://youtube.com/watch?v=bg7O4rtlwEE
>
> In accordance with the formula
>
> (frequency) = (speed of light)/(wavelength),
>
> either
>
> (A) there is a shift in speed of light relative to the observer, proportional to the frequency shift,
>
> or
>
> (B) there is a shift in wavelength inversely proportional to the frequency shift.
>
> The alternative (B) is obviously absurd so the speed of light remains variable, no matter how space and time are vandalized:
>
> "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
>
> Max Planck Institute for Gravitational Physics: "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." https://www.einstein-online.info/en/spotlight/doppler/
>
> "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
>
> "The Doppler effect is the shift in frequency of a wave that occurs when the wave source, or the detector of the wave, is moving. Applications of the Doppler effect range from medical tests using ultrasound to radar detectors and astronomy (with electromagnetic waves)...Moving Observer. Let's say you, the observer, now move toward the source with velocity Vo. You encounter more waves per unit time than you did before. Relative to you, the waves travel at a higher speed: V' = V+Vo. The frequency of the waves you detect is higher, and is given by: f' = V'/λ = (V+Vo)/λ." http://physics.bu.edu/~redner/211-sp06/class19/class19_doppler.html
>
> "The wavelength is staying the same in this [moving observer] case." https://www.youtube.com/watch?v=MHepfIIsKcE
>
> Pentcho Valev https://twitter.com/pentcho_valev

Thank you Pencho. No, please keep posting.

> either
>
> (A) there is a shift in speed of light relative to the observer, proportional to the frequency shift,
>
> or
>
> (B) there is a shift in wavelength inversely proportional to the frequency shift.
>
> The alternative (B) is obviously absurd so the speed of light remains variable, no matter how space and time are vandalized:

(B) is what is taught in text books.

What about Wikipedia?

"The Doppler effect or Doppler shift (or simply Doppler, when in context)[1][2] is the apparent change in frequency of a wave in relation to an observer moving relative to the wave source.[3] It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842."

"Therefore, each wave takes slightly less time to reach the observer than the previous wave. Hence, the time between the arrivals of successive wave crests at the observer is reduced, causing an increase in the frequency"

Apparent increase or increase?

I think it is time we asked the persons who taught us these things for an explanation.

On 2023-05-11 07:56:36 +0000, Athel Cornish-Bowden said:

> On 2023-05-10 22:15:31 +0000, Python said:
>
>> oh shut the f* up, Pentcho !
>
> Too late for that, I fear. He's been at it for at least 25 years and
> he's not going to stop now. He's even picked up a fan or two.

Two at least.

--
athel -- biochemist, not a physicist, but detector of crackpots

gehan.am...@gmail.com <gehan.ameresekere@gmail.com> wrote:

> What about Wikipedia?
>
> "The Doppler effect or Doppler shift (or simply Doppler, when in
> context)[1][2] is the apparent change in frequency of a wave in relation
> to an observer moving relative to the wave source.[3] It is named after
> the Austrian physicist Christian Doppler, who described the phenomenon in
> 1842."
>
>
> "Therefore, each wave takes slightly less time to reach the observer than
> the previous wave. Hence, the time between the arrivals of successive wave
> crests at the observer is reduced, causing an increase in the frequency"
>
> Apparent increase or increase?
>
> I think it is time we asked the persons who taught us these things for an
> explanation.

There is nothing to explain, and nothing 'apparent'.
The frequency is what it is measured to be,
with a spectrograph for example,

Jan