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EINSTEIN'S 1905 THIRD ASSUMPTION



 
 
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  #1  
Old June 1st 13, 02:05 PM posted to sci.astro
Pentcho Valev
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Default EINSTEIN'S 1905 THIRD ASSUMPTION

In 1905 Einstein deduced special relativity from two explicit assumptions - the principle of relativity is valid and the speed of light is independent of the speed of the light source. Yet there was a third assumption, implicit and obviously idiotic:

Assumption 3: The motion of the observer changes the wavelength of light. As the observer starts moving towards the light source with speed v, his motion shifts the wavelength from L to cL/(c+v) so that the product:

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

can remain constant.

Nowadays Einstein's third assumption is explicit and very popular - the idiocy has become common sense:

http://www.lp2i-poitiers.fr/doc/aps/...oppleffet.html
"The observer moves closer to the source. The wave received has a shorter wavelength (higher frequency) than that emitted by the source. The observer moves away from the source. The wave received has a longer wavelength (lower frequency) than that emitted by the source."

http://highered.mcgraw-hill.com/olcw...oppler_Nav.swf
"EXERCISES: 2. Now click on the "Observer Approaches" button. The ship will start flying towards the source. What is the wavelength of the waves now, as the ship approaches the source? Does the frequency increase or decrease? SOLUTIONS: 2. The wavelength shrinks so that about three waves now fit within the graph. (...) The frequency increases."

Pentcho Valev
  #2  
Old June 1st 13, 06:16 PM posted to sci.astro
Pentcho Valev
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Default EINSTEIN'S 1905 THIRD ASSUMPTION

http://www.aip.org/history/einstein/...relativity.htm
John Stachel: "But here he ran into the most blatant-seeming contradiction, which I mentioned earlier when first discussing the two principles. As noted then, the Maxwell-Lorentz equations imply that there exists (at least) one inertial frame in which the speed of light is a constant regardless of the motion of the light source. Einstein's version of the relativity principle (minus the ether) requires that, if this is true for one inertial frame, it must be true for all inertial frames. 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. We have no details of this struggle, unfortunately. Finally, after a day spent wrestling once more with the problem in the company of his friend and patent office colleague Michele Besso, the only person thanked in the 1905 SRT paper, there came a moment of crucial insight. In all of his struggles with the emission theory as well as with Lorentz's theory, he had been assuming that the ordinary Newtonian law of addition of velocities was unproblematic. It is this law of addition of velocities that allows one to "prove" that, if the velocity of light is constant with respect to one inertial frame, it cannot be constant with respect to any other inertial frame moving with respect to the first. It suddenly dawned on Einstein that this "obvious" law was based on certain assumptions about the nature of time always tacitly made."

That is, Einstein explicitly assumed that time behaves so as to make the speed of light independent of the speed of the observer. This assumption was both silly and impudent but the world somehow accepted (and even started to worship) it in the end. However, in order for the speed of light to remain independent of the speed of the observer, another ad hoc assumption was necessary:

The motion of the observer changes the wavelength of the incoming light.

This assumption is even sillier and if Einstein had made it explicitly, relativity would not have been born at all.

Pentcho Valev
  #3  
Old June 2nd 13, 10:07 AM posted to sci.astro
Pentcho Valev
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Default EINSTEIN'S 1905 THIRD ASSUMPTION

For an observer stationary to the light source, the formula fL=c holds (f is frequency, L is wavelength and c is the speed of light relative to that observer). For an observer moving with speed v towards the source, the formula:

f'L' = c'

is valid. We have the special relativity requirement:

c' = c

and also the Doppler formula:

f' = f(1+v/c)

which, for a small v, is an experimental fact.

Clearly the variation of the wavelength with the speed of the observer:

L' = cL/(c+v)

is an implicit but indispensable assumption in special relativity - without it, f'L'=c', c'=c and f'=f(1+v/c) would be incompatible. This assumption is idiotic isn't it?

Pentcho Valev
  #4  
Old June 2nd 13, 02:49 PM posted to sci.astro
Pentcho Valev
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Default EINSTEIN'S 1905 THIRD ASSUMPTION

The following quotations clearly show that, as the observer starts moving towards the light source with speed v, the speed of the light relative to him shifts from c to c'=c+v, in violation of special relativity:

http://www.einstein-online.info/spotlights/doppler
Albert Einstein Institute: "The frequency of a wave-like signal - such as sound or light - depends on the movement of the sender and of the receiver. This is known as the Doppler effect. (...) 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: (...) 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://a-levelphysicstutor.com/wav-doppler.php
"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://www.hep.man.ac.uk/u/roger/PHY.../lecture18.pdf
Roger Barlow, Professor of Particle Physics: "The Doppler effect - changes in frequencies when sources or observers are in motion - is familiar to anyone who has stood at the roadside and watched (and listened) to the cars go by. It applies to all types of wave, not just sound. (...) Moving Observer.. Now suppose the source is fixed but the observer is moving towards the source, with speed v. In time t, ct/(lambda) waves pass a fixed point. A moving point adds another vt/(lambda). So f'=(c+v)/(lambda)."

http://farside.ph.utexas.edu/teachin...ml/node41.html
University of Texas: "Thus, the moving observer sees a wave possessing the same wavelength (...) but a different frequency (...) to that seen by the stationary observer. This phenomenon is known as the Doppler effect."

http://www.donbosco-tournai.be/expo-...fetDoppler.pdf
"La variation de la fréquence observée lorsqu'il y a mouvement relatif entre la source et l'observateur est appelée effet Doppler. (...) 6. Source immobile - Observateur en mouvement: La distance entre les crêtes, la longueur d'onde lambda ne change pas. Mais la vitesse des crêtes par rapport à l'observateur change !"

http://www.radartutorial.eu/11.coherent/co06.fr.html
"L'effet Doppler est le décalage de fréquence d'une onde acoustique ou électromagnétique entre la mesure à l'émission et la mesure à la réception lorsque la distance entre l'émetteur et le récepteur varie au cours du temps. (...) Pour comprendre ce phénomène, il s'agit de penser à une onde à une fréquence donnée qui est émise vers un observateur en mouvement, ou vis-versa. LA LONGUEUR D'ONDE DU SIGNAL EST CONSTANTE mais si l'observateur se rapproche de la source, il se déplace vers les fronts d'ondes successifs et perçoit donc plus d'ondes par seconde que s'il était resté stationnaire, donc une augmentation de la fréquence. De la même manière, s'il s'éloigne de la source, les fronts d'onde l'atteindront avec un retard qui dépend de sa vitesse d'éloignement, donc une diminution de la fréquence. Dans le cas sonore, cela se traduit par un son plus aigu lors d'un rapprochement de la source et un son plus grave en s'éloignant de celle-ci. Dans le domaine de la lumière visible, on parle de décalage vers le bleu pour un rapprochement et vers le rouge dans le cas d'éloignement en se référant au spectre lumineux. La même chose s'applique à toutes les gammes d'ondes électromagnétiques dont les ondes utilisées par les radars."

http://researcher.nsc.gov.tw/public/...1016202571.pdf
Fang-Yuh Lo, Department of Physics, National Taiwan Normal University: "Observer moves toward source: frequency becomes higher. Observer moves away from source: frequency becomes lower. How much higher (lower)? Wavelength does not change. Change in velocity: Vnew=Vwave±Vobs."

http://physics.ucsd.edu/students/cou...cs2c/Waves.pdf
"Doppler effect (...) Let u be speed of source or observer (...) Doppler Shift: Moving Observer. Shift in frequency only, wavelength does not change. Speed observed = v+u (...) Observed frequency shift f'=f(1±u/v)"

http://physics.bu.edu/~redner/211-sp...9_doppler.html
"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). (...) We will focus on sound waves in describing the Doppler effect, but it works for other waves too. (....) 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'/(lambda)=(v+vO)/(lambda)."

http://www.usna.edu/Users/physics/mu...plerEffect.pdf
"Consider the case where the observer moves toward the source. In this case, the observer is rushing head-long into the wavefronts, so that we expect v'v. In fact, the wave speed is simply increased by the observer speed, as we can see by jumping into the observer's frame of reference. Thus, v'=v+v_o=v(1+v_o/v). Finally, the frequency must increase by exactly the same factor as the wave speed increased, in order to ensure that L'=L - v'/f'=v/f. Putting everything together, we thus have: OBSERVER MOVING TOWARD SOURCE: L'=L; f'=f(1+v_o/v); v'=v+v_o."

http://www.cmmp.ucl.ac.uk/~ahh/teach...24n/lect19.pdf
Tony Harker, University College London: "The Doppler Effect: Moving sources and receivers. The phenomena which occur when a source of sound is in motion are well known. The example which is usually cited is the change in pitch of the engine of a moving vehicle as it approaches. In our treatment we shall not specify the type of wave motion involved, and our results will be applicable to sound or to light. (...) Now suppose that the observer is moving with a velocity Vo away from the source. (...) If the observer moves with a speed Vo away from the source (...), then in a time t the number of waves which reach the observer are those in a distance (c-Vo)t, so the number of waves observed is (c-Vo)t/lambda, giving an observed frequency f'=f(1-Vo/c) when the observer is moving away from the source at a speed Vo."

Pentcho Valev
  #5  
Old June 3rd 13, 05:41 PM posted to sci.astro
Pentcho Valev
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Posts: 8,078
Default EINSTEIN'S 1905 THIRD ASSUMPTION

As sane people watch the following video, they see the frequency and the speed of the light waves (relative to the observer) decrease when the observer starts moving away from the source, in violation of special relativity. The wavelength is obviously unaffected by the motion of the observer:

http://www.youtube.com/watch?feature...&v=EVzUyE2oD1w

That the motion of the observer does not affect the wavelength is simply a commonsensical fact valid for all waves:

http://faculty.washington.edu/wilkes...erference..pdf
"Sound waves have speed c, and f and L are related by c=Lf. For an observer moving relative to medium with speed u, apparent propagation speed c' will be different: c'=c±u. Wavelength cannot change - it's a constant length in the medium, and same length in moving coordinate system (motion does not change lengths). Observed frequency has to change, to match apparent speed and fixed wavelength: f'=c'/L."

http://www.einstein-online.info/spotlights/doppler
Albert Einstein Institute: "The frequency of a wave-like signal - such as sound or light - depends on the movement of the sender and of the receiver. This is known as the Doppler effect. (...) 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: (...) 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."

However commonsensical facts are difficult to prove and that is a problem in both Divine Albert's and Big Brother's worlds:

http://ebooks.adelaide.edu.au/o/orwe...hapter1.7.html
"In the end the Party would announce that two and two made five, and you would have to believe it. It was inevitable that they should make that claim sooner or later: the logic of their position demanded it. Not merely the validity of experience, but the very existence of external reality, was tacitly denied by their philosophy. The heresy of heresies was common sense. And what was terrifying was not that they would kill you for thinking otherwise, but that they might be right. For, after all, how do we know that two and two make four? Or that the force of gravity works? Or that the past is unchangeable? If both the past and the external world exist only in the mind, and if the mind itself is controllable what then?"

Pentcho Valev
 




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