But What Does Einstein Mean - Really?
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From: train on 11 Jun 2010 20:00 On Jun 11, 6:30 am, "Androcles" <Headmas...(a)Hogwarts.physics_z> wrote: > "train" <gehan.ameresek...(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 > > "Butit 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"Einsteinhad a violin, not an MP3 player. No TV, no computer, no > Xbox 360, no radio, no car, rode a horse. Hedidwhat 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 Yes but why did he do this? In order to derive a theory?
From: artful on 11 Jun 2010 20:10 On Jun 12, 9:57 am, train <gehan.ameresek...(a)gmail.com> wrote: > 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.. You are confused .. there is no difference. Every inertial frame contains the entire universe. There is no 'within' an inertial frame, as such a frame isn't a containter. There is no 'accross' inertial frames as all inertial frames contain the same events. You really are confused about a very basic notion
From: train on 11 Jun 2010 20:26 On Jun 11, 2:10 pm, harald <h...(a)swissonline.ch> wrote: > 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: > [..] > > > > >Einsteinborrowed 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",butmost > > > 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/MythsSpecR... > > Einsteinmotivates 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,butwithout 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". > > > OKbutthe inverted commas give unnecessary hope to anti relativists > > Why? Anyway, there were no "relativists" and "anti relativists" at > that time. > > [..] > > > > >butnote 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,butis it self consistent? I think the > > twin paradox demonstrates that it is not. > > Time does not flow like waterbutis measured differently; moreover, > not spacebutmoving 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,butthat 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. Stipulates is good, that means it does not logically follow. Of course de Sitters experoment convinced AE no end. > > >ButI 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.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? > > Read it again: no "principle of equivalence" in SRT. You mixed up SRT > and GRT. > > Cheers, > Harald But doesnt AE use the POE in his 1905 SRT paper?
From: train on 11 Jun 2010 20:30 On Jun 11, 6:07 am, "Androcles" <Headmas...(a)Hogwarts.physics_z> wrote: > "train" <gehan.ameresek...(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.Butwe 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 - Sorry I am still not clear about this - assume that in our train experiment, with M and M` etc, the observer on the train and on the tracks each have a radar gun. As M` passes M, they both fire their radar guns at a light pole situated equidistant from themselves. M will see zerospeed on his radar gun. Now M` will see the speed of the train. How does this relate to disproving SRT? Please help me out here...
From: artful on 11 Jun 2010 20:56
On Jun 12, 10:26 am, train <gehan.ameresek...(a)gmail.com> wrote: > On Jun 11, 2:10 pm, harald <h...(a)swissonline.ch> wrote: > > > > > > > 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: > > [..] > > > > > >Einsteinborrowed 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",butmost > > > > 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/MythsSpecR... > > > Einsteinmotivates 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,butwithout 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". > > > > OKbutthe inverted commas give unnecessary hope to anti relativists > > > Why? Anyway, there were no "relativists" and "anti relativists" at > > that time. > > > [..] > > > > > >butnote 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,butis it self consistent? I think the > > > twin paradox demonstrates that it is not. > > > Time does not flow like waterbutis measured differently; moreover, > > not spacebutmoving 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,butthat 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. > > Stipulates is good, that means it does not logically follow. Of course > de Sitters experoment convinced AE no end. > > > > > > > > > >ButI 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.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? > > > Read it again: no "principle of equivalence" in SRT. You mixed up SRT > > and GRT. > > > Cheers, > > Harald > > But doesnt AE use the POE in his 1905 SRT paper? Its the principle of relativity (PoR). Its similar to, but 'weaker' than, the PoE. The PoR says (roughly) that the rules of physics are the same in all inertial frames. The PoE encompasses the PoR, and further says (roughly) that a free-falling frame is equivalent to an inertial frame (for local experiments). |