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As the observer starts moving towards the light source, wavecrests
start hitting him more frequently, that is, relative to the observer, the frequency and the speed of light increase while the wavelength remains constant: 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.expo-db.be/ExposPrecedent...%20Doppler.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.hep.man.ac.uk/u/roger/PHY.../lecture18.pdf Roger Barlow: "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://www.astrosurf.com/quasar95/exposes/redshift.pdf "Appliqué à la lumière, cet effet Doppler-Fizeau engendre un décalage des fréquences émises par une source en mouvement par rapport à un observateur. Comment expliquer ce phénomène ? Par un exemple simple : Une personne est debout sur le rivage d'un bord de la mer. Des vagues lui arrivent sur les pieds toutes les dix secondes. La personne marche, puis court en direction du large (là où se forment les vagues). Elle va à la rencontre des vagues, celles-ci l'atteignent avec une fréquence plus élevée (par exemple toutes les huit secondes, puis toutes les cinq secondes). La personne fait alors demi-tour et marche puis court en direction de la plage. Les vagues l'atteignent avec une fréquence moins élevée, par exemple toutes les douze, puis quinze secondes. Cette petite démonstration s'applique à une onde physique, comme un son, ou ici les vagues sur l'océan pour une meilleure compréhension. Elle peut être extrapolée à une onde lumineuse, en considérant que le sommet d'une vague est le point d'amplitude maximale de l'onde lumineuse." http://www.eng.uwi.tt/depts/elec/sta...relativity.pdf The Invalidation of a Sacred Principle of Modern Physics Stephan J.G. Gift "For a stationary observer O, the stationary light source S emits light at speed c, wavelength Lo, and frequency Fo given by Fo=c/Lo. If the observer moves toward S at speed v, then again based on classical analysis, the speed of light relative to the moving observer is (c + v) and not c as required by Einstein's law of light propagation. Hence the observer intercepts wave-fronts of light at a frequency fA, which is higher than Fo, as is observed, and is given by fA = (c+v)/Lo Fo. (...) In light of this elementary result invalidating STR, it is difficult to understand why this invalid theory has been (and continues to be) accepted for the past 100 years." Usually Einsteinians don't try to contradict this obviously correct interpretation of the Doppler effect (moving observer) but recently Tom Roberts did (in sci.physics.relativity): http://www.msgarchive.net/showthread...EDSHIFT-LUNACY Tom Roberts: "A child knows that if you angle a ruler relative to the object you are measuring, you will get a different answer for its length than if the ruler is aligned properly -- the orientation of the measuring instrument (relative to the object being measured) affects the value it measures. When measuring the wavelength of a given light ray, the orientation in spacetime of your ruler will affect the value you measure. If you are at rest relative to the source, you will measure the same value of wavelength as an observer at the source; if you are moving away from or toward the source, your ruler's orientation in spacetime will be different from that of an observer at the source, and you will measure a longer or shorter value of the wavelength." http://groups.google.com/group/sci.p...238760facf3fb0 JOHN KENNAUGH: "Perhaps you would like to add to your collection the views of the grate Tom Roberts. Me: If I am 1 ly away from a source of light and I change my speed the observed frequency immediately changes. Accepted theory says that the speed of the light arriving has not changed and is still c. If the speed has not changed and the frequency has then there must be a different wavelength. Tom: Correct so far. Me: The wavelength is a function of the speed of separation of the light at the source 1 ly away. Tom: This is grotesquely wrong. Me: It is absolutely right. Tom: Nonsense. The "speed of separation of the light at the source" is c, a single value. Me: Only in the FoR of the source. Tom: If wavelength were indeed a function of the speed of separation from the source, then all light would necessarily have a single wavelength -- it doesn't. Your basic error is saying "the wavelength", implicitly thinking it is a property of the light; it isn't. It requires an instrument to measure the wavelength of light, and the value obtained depends on properties of the instrument (e.g. its velocity wrt the source of the light). Me: How can the RELATIVE velocity of the source affect my ruler or the clock of my frequency counter? Tom did not respond. _________________________________________ end of John Kennaugh's text Pentcho Valev |
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