But What Does Einstein Mean - Really?
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From: Androcles on 10 Jun 2010 21:07 "train" <gehan.ameresekere(a)gmail.com> wrote in message news:27517976-1984-4779-a5a8-828303fe9798(a)u3g2000prl.googlegroups.com... On Jun 10, 10:41 pm, "Androcles" <Headmas...(a)Hogwarts.physics_z> wrote: > "harald" <h...(a)swissonline.ch> wrote in message > > news:c043d370-515b-4992-a1f0-4483cf995871(a)i31g2000yqm.googlegroups.com... > > Nobody can see photons flying; what we can see is the scattering of > light on particles. In other words, we can only directly see light > that falls on our eyes, and our eye does not tell us if it was a > photon, ray, or wave. > > =============================================== > Or what its speed is. We get that from it's emission colour and its > observed > colour. > > Professor C.A.Doppler had it work out, > f' = f *(c+v)/c > cf' = f *(c+v) > cf'/f = c+v > cf'/f - c = v > v = c(f'/f-1) > > Whether the car comes to the radar gun or the radar gun goes to the car, > the relative speed is v. Hence Doppler radar and a speeding ticket for > travelling at speed v. > The speed of light relative toEinstein's > superfluous aether = > superfluous empty space = > superfluous stationary frame of reference = > superfluous inertial frame = > superfluous absolute frame = > is non sequitur, > the speed of light relative to the emitter, c, is pertinent. > > Radar guns work just fine (by millions of experiments) proving > thatEinsteinwas a jerk, his calculation V = (c+v)/(1+v/c) = c is > nonsense and would not agree with radar gun experiments. > http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img76.gif Not sure how the radar gun invalidates SRT. =============================== Hmm... MMX has a null result (i.e. if a radar gun was the MMX source of light beside the detector and the car was the mirror then the readout is always zero velocity = no Doppler shift = no fringe shift). Ok, so the car is parked. But we know that the supposed solution to MMX is length contraction as per SR. This is because the speed of light is c in the universal aether frame system inertial absolute reference wotsit "stationary" (and any other words used to mean the same thing without ever agreeing that it exists), and the Earth and the radar gun and the car and MMX all moving together through the universal aether frame system inertial absolute reference wotsit "stationary" (and any other words used to mean the same thing without ever agreeing that it exists). Unfortunately for SR the radar gun works, the car moves, there are fringe shifts in MMX when the mirror moves toward or away from the source. According to SR, we cannot simply compute c+v, we have to use http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img76.gif = [c] which I'll put in square brackets to represent (c+v)/(1+v/c)= [c] So Doppler radar guns don't work in SR, f' = f .[c]/c = f * 1 = no shift, where [c] = (c+v)/(1+v/c) Hence millions of cops doing real experiments around the world have disproven SR. ================================================ In any case the difference cannot be that great and you still get your speeding ticket? `Radar guns are, in their most simple form, radio transmitters and receivers. They send out a radio signal, then receive the same signal back as it bounces off the objects. However, the radar frequency is different when it comes back, and from that difference the radar gun can calculate object speed. A radar beam is similar to a beam of light in that it spreads out as the distance from the signal origin increases. The signal then bounces off objects in the path of the beam and are reflected back to the gun. The gun uses the Doppler effect to calculate the speed of the object in the beam's path. Using a comparison of frequency shift between received images instead of the frequency shift between sent and received frequencies creates what is known as moving radar. Unless the radar system has a provision for converting own-vehicle-speed to an appropriate receiver frequency offset then the radar must be stationary to measure speed.` Wikipedia What if a radar gun was used on a moving train thought experiment -
From: Androcles on 10 Jun 2010 21:30 "train" <gehan.ameresekere(a)gmail.com> wrote in message news:acabac4d-09c7-4f6e-b48d-b02dd727bc05(a)40g2000pry.googlegroups.com... On Jun 10, 10:41 pm, "Androcles" <Headmas...(a)Hogwarts.physics_z> wrote: > "harald" <h...(a)swissonline.ch> wrote in message > > news:c043d370-515b-4992-a1f0-4483cf995871(a)i31g2000yqm.googlegroups.com... > > Nobody can see photons flying; what we can see is the scattering of > light on particles. In other words, we can only directly see light > that falls on our eyes, and our eye does not tell us if it was a > photon, ray, or wave. > > =============================================== > Or what its speed is. We get that from it's emission colour and its > observed > colour. > > Professor C.A.Doppler had it work out, > f' = f *(c+v)/c > cf' = f *(c+v) > cf'/f = c+v > cf'/f - c = v > v = c(f'/f-1) > > Whether the car comes to the radar gun or the radar gun goes to the car, > the relative speed is v. Hence Doppler radar and a speeding ticket for > travelling at speed v. > The speed of light relative toEinstein's > superfluous aether = > superfluous empty space = > superfluous stationary frame of reference = > superfluous inertial frame = > superfluous absolute frame = > is non sequitur, > the speed of light relative to the emitter, c, is pertinent. > > Radar guns work just fine (by millions of experiments) proving > thatEinsteinwas a jerk, his calculation V = (c+v)/(1+v/c) = c is > nonsense and would not agree with radar gun experiments. > http://www.fourmilab.ch/etexts/einstein/specrel/www/figures/img76.gif Ok, more of what AE said, from the 1905 paper " But it is not possible without further assumption to compare, in respect of time, an event at A with an event at B. We have so far defined only an ``A time'' and a ``B time.'' We have not defined a common ``time'' for A and B, for the latter cannot be defined at all unless we establish by definition that the ``time'' required by light to travel from A to B equals the ``time'' it requires to travel from B to A" If A and B are stationary srt each other why is this necessary, if A and B are not, why is this possible - if A and B are moving parallel towards each other then AB is not equal to BA. Right? ============================================= Its a simple logical error. Some umbrellas are up when it rains. We establish by definition that umbrellas are up if it rains, for we have not defined a common state for a umbrellas to be in. It is raining. Therefore all umbrellas are up. All triangles are isosceles. http://www.jimloy.com/geometry/every.htm "first published by W. W. Rouse Ball in 1892" Einstein had a violin, not an MP3 player. No TV, no computer, no Xbox 360, no radio, no car, rode a horse. He did what few teenagers do today, he read magazines and newspapers. So he read about W. W. Rouse Ball. Was he huckster or idiot? http://www.androcles01.pwp.blueyonder.co.uk/Shapiro/Crapiro.htm
From: harald on 11 Jun 2010 05:10 On Jun 11, 1:48 am, train <gehan.ameresek...(a)gmail.com> wrote: > On Jun 10, 8:53 pm, harald <h...(a)swissonline.ch> wrote: [..] > > > > Einstein borrowed that phrasing from common language as used by > > > > Maxwell and Lorentz. In order to give it operational meaning for the > > > > purpose of the theory, he redefined the light postulate as follows: > > > > > "Any ray of light moves in the ``stationary'' system of co-ordinates > > > > with the determined velocity c, whether the ray be emitted by a > > > > stationary or by a moving body." > > > > > Harald > > > > OK let me parse that sentence > > > > > "Any ray of light moves > > > > `ray of light` is that not inexact since a ray of light consists of a > > > visible stream of photons ie ray of sunlight? Maybe he met the tip of > > > the ray of light? > > > Nobody can see photons flying; what we can see is the scattering of > > light on particles. In other words, we can only directly see light > > that falls on our eyes, and our eye does not tell us if it was a > > photon, ray, or wave. > > > Einsteinmight have been clearer if he stated "light wave",but most > > people concerned understand how light speed can be measured. > > OK > > BTW this group is becoming really good. Like old wine. > > > > in the ``stationary'' system of co-ordinates > > > > why the inverted commas? Why stationary why not say `observer` or > > > `target` system of coordinates? Stationary wrt to what? Because it's only an inertial system that he *treats* as "stationary" - just as in Newtonian physics. It is common practice to state that something is "in rest", pretending that it has zero speed and zero momentum, without any "absolute" meaning. It is however inconsistent with the original meaning of the formulation in the introduction which he borrowed from Maxwell and Lorentz, while he pretends that he didn't change its meaning, he just wipes it under the carpet - thus planting the seeds of the confusions of others*. *Discussed here: http://www.uio.no/studier/emner/matnat/fys/FYS-MEK1110/v06/MythsSpecRelativAJP193.pdf Einstein motivates in other writings that it makes perfect sense that the (two-way) speed of light is measured to be c in all directions; and that suggestion is also contained in his claim that the theory is "based on Maxwell's theory for stationary bodies". However, that is only fully correct if "stationary" has an absolute sense. It looks as if he first based himself truly on Maxwell-Lorentz and then after he got his results, he backtracked to remove all notion of absolute motion in his introduction, but without fully succeeding. The result is messy: the second postulate in his second formulation still applies to only one arbitrarily chosen inertial system, for else it would *not* be "apparently irreconcilable" with the principle of relativity. Probably he added his remark that he didn't need to introduce the stationary ether for his derivation afterwards. > > He already explained that: "take a system of co-ordinates in which the > > equations of Newtonian mechanics hold good" and "call it the > > ``stationary system''", in order to "distinguish this system of co- > > ordinates verbally from others which will be introduced hereafter". > > OK but the inverted commas give unnecessary hope to anti relativists Why? Anyway, there were no "relativists" and "anti relativists" at that time. [..] > > > but note talking about the behavior of light within a coordinate > > > system - coordinate box I call it - does not say anything about the > > > behaviour between coordinate systems > > > That is exact, and even the central issue of SRT. As he put it: the > > [light postulate] is only apparently irreconcilable with the > > [relativity postulate]. > > Well sure if you take time to flow like water and space to contract > you can squeeze the theory in, but is it self consistent? I think the > twin paradox demonstrates that it is not. Time does not flow like water but is measured differently; moreover, not space but moving objects are measured to be contracted in SRT. And what is nowadays (mis)called twin paradox never was paradoxical for those who understood the theory, as it is perfectly self consistent; it's even a standard textbook exercise. The original "twin paradox" only appeared with the development of GRT, but that is a different and more difficult topic. > > > or reference box as I call it - > > > unless you take the additional step of saying that light emitted in > > > another reference box will travel at c in your reference box - why is > > > he saying this? > > > ????! Light is not "emitted in a reference box", and the light > > postulate already states that light that is emitted from a moving body > > (according to your system) will be measured to travel at c with your > > coordinate system and clocks. That is not an additional step, as it > > had already been stated. > > Yes there is a subtle step - say there at two labs A and B, A has a > source and target stationary wrt itself, so has B. Inside A and B > scientists measure the velocity of light to be c and c respectively. So far you don't have motion of the source, which is the essential point of the second postulate. > If the labs A and B are moving wrt each other Ok, now some of the sources are "moving", as in the second postulate. > , it cannot be assumed > that the light emitted in lab A , when measured by lab B , will be > measured at c, unless you stipulate that the speed of light will be > always measured at c anywhere. As explained above several times: the second postulate stipulates that the light emitted in lab B ("the moving body"), when measured by lab A (the "stationary system"), will be measured at c. > But I think you answered this when you > said the equivalence principle is not involved. No, see below. > Is it the principle of equivalence? No. The PoE is about acceleration and gravitation. > > No, the second postulate states that the speed of light is not > > affected by the speed of the emitting system, and will still travel at > > c according to your measurements. That is the light postulate. > > > > I will describe > > > how the principle of equivalence has been wrongly applied here . > > > It is not applied in SRT. > > OK Harald we agree. But do you realize what I said that AE incorrectly > cites the equivalence principle as a basis for SRT or have I misread > the Great Scientist? Read it again: no "principle of equivalence" in SRT. You mixed up SRT and GRT. Cheers, Harald
From: maxwell on 11 Jun 2010 14:08 On Jun 10, 8:53 am, harald <h...(a)swissonline.ch> wrote: > On Jun 10, 1:58 am, train <gehan.ameresek...(a)gmail.com> wrote: > > > > > > > On Jun 8, 9:03 pm, harald <h...(a)swissonline.ch> wrote: > [..] > > > > Tis strange. I always thought that saying light propagates at a rate > > > > of c without giving any stipulation relative to what it was measured > > > > against was strange. This confirms that there is no basis for speed > > > > relative to empty space. I cannot accept this definition. > > > > > An astronaut floats in space, at what velocity is he moving? > > > > Einstein borrowed that phrasing from common language as used by > > > Maxwell and Lorentz. In order to give it operational meaning for the > > > purpose of the theory, he redefined the light postulate as follows: > > > > "Any ray of light moves in the ``stationary'' system of co-ordinates > > > with the determined velocity c, whether the ray be emitted by a > > > stationary or by a moving body." > > > > Harald > > > OK let me parse that sentence > > > > "Any ray of light moves > > > `ray of light` is that not inexact since a ray of light consists of a > > visible stream of photons ie ray of sunlight? Maybe he met the tip of > > the ray of light? > > Nobody can see photons flying; what we can see is the scattering of > light on particles. In other words, we can only directly see light > that falls on our eyes, and our eye does not tell us if it was a > photon, ray, or wave. > > Einstein might have been clearer if he stated "light wave", but most > people concerned understand how light speed can be measured. > > > in the ``stationary'' system of co-ordinates > > > why the inverted commas? Why stationary why not say `observer` or > > `target` system of coordinates? Stationary wrt to what? > > He already explained that: "take a system of co-ordinates in which the > equations of Newtonian mechanics hold good" and "call it the > ``stationary system''", in order to "distinguish this system of co- > ordinates verbally from others which will be introduced hereafter". > > > > > > > > with the determined velocity c, > > > OK > > > whether the ray be emitted by a > > > the ray of light again > > > > stationary or by a moving body." > > > sounds a lot like Personal Ether Theory to me PET Theory > > > it goes something like this- > > > `each observer is floating in a virtual personal ether that extends to > > infinity and which entrains, entraps, restricts and otherwise > > constrains all photons to travel at c relative to that observer` > > No. That postulate is compatible with a stationary ether model (it > even stems from the use of that model by Lorentz), but it is *not* > compatible with entrained ether models (just think about it: the speed > of light as measured in the solar system would then not be c near the > earth). And it has been argued - despite Einstein's suggestion to the > contrary - that his light postulate is only compatible with stationary > ether models. > > > but note talking about the behavior of light within a coordinate > > system - coordinate box I call it - does not say anything about the > > behaviour between coordinate systems > > That is exact, and even the central issue of SRT. As he put it: the > [light postulate] is only apparently irreconcilable with the > [relativity postulate]. > > > or reference box as I call it - > > unless you take the additional step of saying that light emitted in > > another reference box will travel at c in your reference box - why is > > he saying this? > > ????! Light is not "emitted in a reference box", and the light > postulate already states that light that is emitted from a moving body > (according to your system) will be measured to travel at c with your > coordinate system and clocks. That is not an additional step, as it > had already been stated. > > > Is it the principle of equivalence? > > No, the second postulate states that the speed of light is not > affected by the speed of the emitting system, and will still travel at > c according to your measurements. That is the light postulate. > > > I will describe > > how the principle of equivalence has been wrongly applied here . > > It is not applied in SRT. > > Harald Don't use "seeing" as a primitive. Vision is a vastly complex activity in animals with multi-trillion brain cells, many of these cells devoted to the PROCESS called "vision". What we might imagine to be occurring at the level of atoms & electrons is all theory that must be related (through more levels of theory) to the macroscopic phenomena that we can talk about. In my view, the primitive THEORETICAL process is the interaction between TWO electrons. When this is aggregated to human levels we call it "light".
From: train on 11 Jun 2010 19:57
On Jun 11, 6:11 am, "whoever" <whoe...(a)whereever.com> wrote: > "train" <gehan.ameresek...(a)gmail.com> wrote in message > > news:533e1780-0c0e-4bac-86f6-577aa4a1cd6d(a)s4g2000prh.googlegroups.com... > [snip] > > > Well sure if you take time to flow like water and space to contract > > you can squeeze the theory in,butis it self consistent? I think the > > twin paradox demonstrates that it is not. > > There is no paradox. It is not inconsistent .. it is perfectly > self-consistent. Just surprising the first time you see it. > > [snip] > > > Yes there is a subtle step - say there at two labs A and B, A has a > > source and target stationary wrt itself, so has B. Inside A and B > > scientists measure the velocity of light to be c and c respectively. > > If the labs A and B are moving wrt each other, it cannot be assumed > > that the light emitted in lab A , when measured by lab B , will be > > measured at c, unless you stipulate that the speed of light will be > > always measured at c anywhere. > > It cannot be assumed,butit is fonud to be the cast experimentally the > light speed does not depend on the speed of the source. The second > postulate of SR is found to hold > > [snip] > > > OK Harald we agree.Butdo you realize what I said that AE incorrectly > > cites the equivalence principle as a basis for SRT or have I misread > > the Great Scientist? > > It is PART of the basis. If you cannot assume that the rules of physics > apply the same in all (inertial) frames, then you cannot use those rules to > derive SR from constant light speed. > > --- news://freenews.netfront.net/ - complaints: n...(a)netfront.net --- The difference is between within inertial frames and acrosss inertial frames.. |