Doesn't the interpretation of red/blue spectrum shift violate contancy of speed of light?
in [Relativity]
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From: Dougie Excel on 26 Feb 2010 11:37 I need an explanation: It's well known that the fact that most objects in the universe have a spectral signature that is shifted to the 'blue' end of the spectrum is interpreted as proof most objects are moving away from us. Usually this is analogized to the doppler effect with regard to sound waves, where the wavelengths of sound from a source moving towards you are shorter than when the source is moving away from you. However, isn't the sound coming at you from a source that is moving towards you compressed into a shorter wavelength because it is actually moving towards you at a higher rate of speed (ie it's moving towards you at the speed of sound + the speed of the source)? If this is the case, I don't see how it could function with regard to light - the rare 'red shift' of a object moving towards the earth would then be explained by light being compressed into a shorter wavelength because it is moving at the speed of light + the speed of the source; however, due to relativity the light approaches us at the same speed no matter of the relative speed of the source, so wouldn't any red shift in fact reflect not the object's movement relative to us but rather than actual elemental make-up of the object? = Doug
From: Igor on 26 Feb 2010 11:52 On Feb 26, 11:37 am, Dougie Excel <DouglasWilliamSm...(a)Yahoo.Com> wrote: > I need an explanation: > > It's well known that the fact that most objects in the universe have a > spectral signature that is shifted to the 'blue' end of the spectrum > is interpreted as proof most objects are moving away from us. Usually > this is analogized to the doppler effect with regard to sound waves, > where the wavelengths of sound from a source moving towards you are > shorter than when the source is moving away from you. > > However, isn't the sound coming at you from a source that is moving > towards you compressed into a shorter wavelength because it is > actually moving towards you at a higher rate of speed (ie it's moving > towards you at the speed of sound + the speed of the source)? > > If this is the case, I don't see how it could function with regard to > light - the rare 'red shift' of a object moving towards the earth > would then be explained by light being compressed into a shorter > wavelength because it is moving at the speed of light + the speed of > the source; however, due to relativity the light approaches us at the > same speed no matter of the relative speed of the source, so wouldn't > any red shift in fact reflect not the object's movement relative to us > but rather than actual elemental make-up of the object? > > = Doug You've actually gotten it backwards. Light moving away from an observer is blue shifter. Toward an observer, it's red shifted. And neither have any bearing on the speed of light since frequency changes accordingly. With regard to your last question, the elemental makeup is characterised by spectral lines, which get shifted as well, based on relative motion of observer and source.
From: Androcles on 26 Feb 2010 12:17 "Dougie Excel" <DouglasWilliamSmith(a)Yahoo.Com> wrote in message news:65971ad5-4428-4388-b7f1-396409c2740e(a)e23g2000yqd.googlegroups.com... >I need an explanation: > > It's well known that the fact that most objects in the universe have a > spectral signature that is shifted to the 'blue' end of the spectrum > is interpreted as proof most objects are moving away from us. Usually > this is analogized to the doppler effect with regard to sound waves, > where the wavelengths of sound from a source moving towards you are > shorter than when the source is moving away from you. > Consider what happens when the source of sound is stationary in air and the listener is moving. http://androcles01.pwp.blueyonder.co.uk/PoR/PoR.htm > However, isn't the sound coming at you from a source that is moving > towards you compressed into a shorter wavelength because it is > actually moving towards you at a higher rate of speed (ie it's moving > towards you at the speed of sound + the speed of the source)? Only if the wind isn't blowing at the same speed as the sound source. > If this is the case, I don't see how it could function with regard to > light - the rare 'red shift' of a object moving towards the earth > would then be explained by light being compressed into a shorter > wavelength because it is moving at the speed of light + the speed of > the source; however, due to relativity the light approaches us at the > same speed no matter of the relative speed of the source, so wouldn't > any red shift in fact reflect not the object's movement relative to us > but rather than actual elemental make-up of the object? > > = Doug You are thinking on the right lines. What many people fail to realise is Einstein failed mathematics and physics but scored top marks in bullshit. -- Androcles Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img22.gif What kind of lunacy prompted Einstein to say the speed of light from A to B is c-v, the speed of light from B to A is c+v, the "time" each way is the same?
From: Androcles on 26 Feb 2010 12:19 "Igor" <thoovler(a)excite.com> wrote in message news:67989efe-d19f-4442-ac2e-471e67cf4b84(a)u9g2000yqb.googlegroups.com... On Feb 26, 11:37 am, Dougie Excel <DouglasWilliamSm...(a)Yahoo.Com> wrote: > I need an explanation: > > It's well known that the fact that most objects in the universe have a > spectral signature that is shifted to the 'blue' end of the spectrum > is interpreted as proof most objects are moving away from us. Usually > this is analogized to the doppler effect with regard to sound waves, > where the wavelengths of sound from a source moving towards you are > shorter than when the source is moving away from you. > > However, isn't the sound coming at you from a source that is moving > towards you compressed into a shorter wavelength because it is > actually moving towards you at a higher rate of speed (ie it's moving > towards you at the speed of sound + the speed of the source)? > > If this is the case, I don't see how it could function with regard to > light - the rare 'red shift' of a object moving towards the earth > would then be explained by light being compressed into a shorter > wavelength because it is moving at the speed of light + the speed of > the source; however, due to relativity the light approaches us at the > same speed no matter of the relative speed of the source, so wouldn't > any red shift in fact reflect not the object's movement relative to us > but rather than actual elemental make-up of the object? > > = Doug You've actually gotten it backwards. Light moving away from an observer is blue shifter. Toward an observer, it's red shifted. ================================================== According to the back-arsewards lunatic Igor hoovler, the universe is contracting. Idiot!
From: dlzc on 26 Feb 2010 12:50
Dear Dougie Excel: On Feb 26, 9:37 am, Dougie Excel <DouglasWilliamSm...(a)Yahoo.Com> wrote: > I need an explanation: > > It's well known that the fact that most > objects in the universe have a spectral > signature that is shifted to the 'blue' .... no 'red' ... > end of the spectrum is interpreted as > proof most objects are moving away from > us. And not so much proper motion, as a combined effect of "kinetic motion", expanding space, and different positions in gravity wells. > Usually this is analogized to the doppler > effect with regard to sound waves, where > the wavelengths of sound from a source > moving towards you are shorter than when > the source is moving away from you. Yes. If you were moving with the light in some magical way, there would be *no* frequency and infinite wavelength... not that this becomes at all helpful. > However, isn't the sound coming at you > from a source that is moving towards you > compressed into a shorter wavelength > because it is actually moving towards > you at a higher rate of speed (ie it's > moving towards you at the speed of sound > + the speed of the source)? This ignores the medium that brakes the "sound" to the local speed of the medium, not that this applies to light. > If this is the case, .... it isn't ... > I don't see how it could function with > regard to light - the rare 'red shift' > of a object moving towards .... away from ... > the earth would then be explained by light > being compressed .... rarefied ... > into a shorter .... longer ... > wavelength because it is moving at the > speed of light + .... - ... > the speed of the source; however, due to > relativity the light approaches us at the > same speed no matter of the relative speed > of the source, Relativity does not require this. Relativity relies on Maxwell's equations, that give a constant speed of light as a result. The second postulate is "redundant". > so wouldn't any red shift in fact reflect > not the object's movement relative to us > but rather than actual elemental make-up > of the object? No. What we measure in a signal has components: 1) of the emitting process, 2) at the speed the source was moving, 3) in the gravity well it was emitted in, 4) in the epoch of its emittance (size of Universe), 5) in the epoch of its detection, 6) in the gravity well it was detected, 7) in the speed of the detector 8) in the detection process #5-8 we can self-correlate, and we can use similarity to account for #1, and #3. We do a "drunkard's walk" to estimate #4, which leaves some handle for #2. We can ever only measure light speed to be c. We've tried lots of different ways: http://www.physics.adelaide.edu.au/~dkoks/Faq/Relativity/SR/experiments.html#Tests_of_Einsteins_two_postulates So, given that Maxwell was apparently right... what will you do to wrap your head around this? David A. Smith |