Hi Pete Lets start with a quote from http://www2.slac.stanford.edu/vvc/theory/relativity.html If we take a spherical light source with a uniform emission pattern and walk around it there would be no change in the light's intensity. If we let the light source have a velocity with respect to an external observer and repeat the "walk around" we would not detect any change in intensity. This jives with the second postulate above. If a light source changes its emissive pattern as a responce to velocity as you statted "But the motion of the ship at the instant of emission determines the direction of emission." then there is a problem with the second postulate above. Any change in the direction of emission would change the intensity we would see in a "walk around". The only conclusion I can come up with is that the change in light's emission vector happens in the observers frame at the observer. Is there a flaw in my logic? Please Register or Log in to view the hidden image!
The problem with this originates with Einstein's development of SRT described in "relativity" published 10 years after his original paper was published. AE uses the train gedanken and starts by comparing a light source on the embankment (the "vacua") with a moving train. All observations are taken from the embankment, though it appears that AE has moved the source onto the train and that the observations are from the train as the inertial frame (see chapter 7). This is an Einsteinian shell game. If you take the time to review the matter you will prove it to yourself. AE started with the man walking on the train and arrives correctly at the expression that the man's velocity seen from the embankment is, Vme = Vte + Vmt or that the man's total velocity is the sum of the train velocity wrt the embankment plu the man's velocity wrt the train. Now the fun begins. AE substitutes light velocity for the man's velocity and arrives at, Vle = Vte + Vlt, or Vle - Vte = Vlt. From this AE claims that Vlt is less than the velocity of light wrt the embankment and then claims that "relativity" constraints insist that the laws governhing the motion of light on the embankment and the train should be the same (as we all know the laws of physics on inertial frames are iontercfhangeable. This does not mean the answers will come out the same, such as measuring relative motion of an object from various inertial frames.) The laws of motion are the same but to assert that the speed of light must be measured the same in all intertial frames, as opposed to all other physical matter, is arbitrary and a misuse of the statement, "the laws governing light motion must be the same in the embankment as well as on the train." AE gives NO proof that light has to be considered differently than other material objects Looking at the statement, Vle - Vte = Vlt, we see the simple statement that the speed of light is greater than the speed of the train by the amount expressed. There is no contradiction of the laws of motion of light. Look at what AE has done with his expression. He substitutes light motion for the man walking on the train when he had just stated (chapter 7) that the speed of light is independent of the speed opf the source of the light! To correct AE, we must correct the term Vlt, the speed of light wrt the speed of the train. Simply, we recognize that we must subtract the speed of the train from the expression, Vlt, or Vlt = V'le - Vte, then when we substitute into the "man's velocity", we arrive at, Vle = Vte + Vlt or Vle = Vte + V'le - Vte = Vle = V'le where I inserted the prime to distinguish the measurement of the light originating on the train (or trhe embankment for that matter as the results are identical). Your classification of inertiqal frames is incorrect as a matter of physical law, but is the correcty dogma of SRT. You (SRT theory) has two speeds of light when only oine exists. Mental observation and psychological perception do not alter physical reality though the early quantum theorists thought so in the early days. CANGAS is correct in all respects. The predictions are as he stated. Using SRT the speed of light must exceed c in order to conform to the laws of physics, an impossibility. It is not a matter of disbelieving the postulates of physics (SRT), it is a matter of proving them in error. AE, while a historical "genius" to some, is a laughing matter to others- personalities prove nothing, wide held beliefs prove nothing, majority of scientific opinion prove nothing. Pete, you have never described the origins of the SRT in a critical mode, using the proof presented by AE, why not exercise your mind and ours at the same time and prove what you claim. Geistkiesel
If you get that the speed of light is not c then you have violated the 2nd postulate and you are not talking about SR. Sorry GK, inventing some flawed strawman theory and then pretending it is SR does not magically make it so. -Dale
Hi Montec, I'm not clear on your second walkaround. Is it the external observe that is walking around? How fast are they walking? Where is the light source when the walkaround begins? Where is it when the walkaround ends?
Hi Pete The "walk arounds" occur in the light source frame at a non-relativistic speed. The observer is another frame that has a velocity with respect to the light source frame. The beginning and end positions for the walk around can be the vector line between the two frames IE the line between the observer and light source. Please Register or Log in to view the hidden image!
Pete You always have a dam lot of questions and never have ANY REAL answers. I am never surprised to see this. You know that I know that you are a phony. Youn are only capable of imitating true intelligence, not of actually exercising such a thing. Are you an artificial intelligence simulation? A first edition, flawed version?
My post clearly demonstrated that Special Relativity blatantly produces gross contradictions abhorrant to common logic. All that has been given in rebuttal is vague comments that my post does not comply with the great god RELATIVITY. No specific proofs of wrongness. No specific illustrations of logical failure. No accusations of incorrectness except that it does not agree with Special Relativity. Please, a little less arm waving and shouting, and a little more SPECIFIC debate on SPECIFIC points where my logic or my mathematics is wrong.
Geistkiesel: Here, Einstein must be referring to Galilean relativity, since the given expression is false for Einsteinian relativity. As an approximation, the equation holds for speeds which are small compared to the speed of light. In other words, Einstein is showing that Galilean relativity cannot be correct, and must be replaced by his Special Theory of Relativity. Einstein shows that using Galilean relativity leads to absurdities which are not seen in real experiments. The assertion that the speed of light is the same in all inertial reference frames is indeed arbitrary. It has no justification a priori. Hence, Einstein makes it quite clear that it is an unproven postulate of special relativity. The postulate, of course, is shown to be correct a posteriori by experimental results. Yes he does. Read his very first paper, on the electrodynamics of moving bodies. Electromagnetism would be inconsistent without special relativity. There's no contradiction in Galilean relativity, true. But experiments and electromagnetic theory show that this is a real problem and doesn't work. Which is why Einstein was considering the matter in the first place. Yes. He does a marvelous job of showing that Galilean relativity is inconsistent with his postulate, don't you think? A very clever man, old Albert. I don't know where you got this idea. Perhaps it is because you can't distinguish Galilean relativity from Special Relativity... Indeed. So, got any evidence that they are in error? Nobody else has provided anything in the last 100 years, but maybe you can. Correct. Almost invariably, though, it turns out that those who laugh at Einstein have never achieved anything of note in physics themselves, and they usually have serious misconceptions about relativity. They just don't understand the theory they are trying to avoid coming to grips with.
Welcome back Geistkiesel! I like to think about alternative theories, but it is not always clear what they might be proposing. When you say this: You seem to be equating the embankment frame with an absolutely stationary vaccum. Your equations seem to have light moving at c only in this reference frame. But, how do we know that the embankment frame has this preferred status? Is it carrying the vacuum around with it, or is it at absolute rest? For example, if an evacuated tube is moving (relative to something) at some relativistic velocity, is it carrying the enclosed vacuum with it? Will light move at c or some other speed within the tube's frame? Classically, waves propagate at a constant speed relative to their medium. I am just trying to understand how a vacuum could be considered a medium when it is essentially nothingness in and of itself.
ROFL, you can't even be self-consistent within a single post. You admit that your scenario does not comply with SR immediately after claiming that it demonstrates something about SR. Keep sniffing that CAN-o'-GAS if you wish, but if you violate the postulates of SR you are simply not talking about SR. You are merely setting up a strawman, knocking it over with a few weak punches, and claiming to have defeated the heavyweight champion. It is delusional, like most anti-SR posts. Claiming that something is SR when it is not SR is both wrong and a logical failure. That is sufficient for debunking a claimed disproof of SR. SR: It is going to rain today CANGAS: SR said it would be sunny and it rained! SR is wrong! Dale: SR said it would rain, you said it would be sunny, so you weren't talking about what SR said. CANGAS: You haven't proved me wrong except that I didn't agree with SR! The specific point where your logic is wrong is where you claim that it has anything whatsoever to do with SR. I have demonstrated this already and you have already conceeded the point. What more debate do we need? The issue is resolved, some theory is wrong, that theory is not SR. -Dale
Neddy Bate, I was hoping you would respond to my post. It is good to hear from again. I have always respected your replys and your gentlemanly nature has the effect of minimizing some of my disagreeable traits, which I do strive to contain (not always successful) within acceptable boundaries. If I were to emit a pulse of light in the embankment, or in the train (that is open at both ends of the train segment) and measure the train and light speed wrt the embankment, I would arrive at the relative speed of frame and photon wrt the embankment, correct? The "media of both train and embankment" are identical in this case. I am using AE's description as written in his "Relativity" (Chapter 7) published 10 years after the 1905 paper. The embankment and the vacua are identical according to AE here. You must consult AE for a definitive answer to the specifics of your question. I don't have his e-mail address, sadly. It is only after AE describes the man walking and describes his speed wrt the embankment as Vme = Vte + Vmt (the velocity of the man wrt the emnbankment is the sum of the speed of the train wrt the embankment plus the speed of the man wrt the train). We cannot substitute light motion for the man motion as this assumes that light emitted in the direction of the train would have the train velocity as an added velocity component, correct? This is violating the independence postulate of light motion where light speed is independent of the speed of the source of the light. This says absolutely nothing about "equivalent frames of reference", or "observer's perceptions". If we did substitute the light for the man directly, we would arrive at, Vle = Vte + Vlt, or rearranging, Vle - Vte = Vlt. As Vlt is less than c, have we made any error here? No, we have merely measured the relative velocity of frame and photon as measured wrt the embankment. If we used the same form of AE's equations here, we must first write Vlt = V'le - Vte, or we subtract the train motion, which is not identical to setting the train velocity to zero! The prime refers to the light emitted on the train,which is to be determined. The unprimed is the speed of light measured from the embankment. This we would do for the man walking on the train, only. Now when we use Vle = Vte + Vlt and substitute our correction, we arrive at, Vle = Vlt + V'le - Vte, or Vle = V'le, which is what we expect. Where did SRT go? The prime is correct as the train observer will always see a tie in a race of pulses emitted on the train racing against pulses emitted in the embankment, correct? Do you agree? Something to consider: The twin oparadox is reolved by asserting that the accelerated twin will age slower, hence the equivalence of inertial frames does not apply here. Trains and accelrated space ships must be treated identically, correct? Geistkiesel
No, quite the opposite. I said that if one assumes that the light emitted perpendicular to the motion of the emitter and maintains the motion of the emitter then the speed of light will be greater than c. This violates the independence postulate of light motion, where light motion, speed, is independent of the motion of the source. SRT violates this postulate. Geistkiesel
Only if you assume that the component of the light's velocity perpendicular to the emitter is c in all frames. This isn't true in relativity.
You are correct that the given expression is false for Einsteinian relativity. But no, was not referring to Galilean relativity. AE simply constructed the equation measured wrt to the embankment, and then without further ado, made the assumption that light could be asubstiotuted for the man's walking motion knowiong that light does not assume the motion of the source of the light as did the man's speed. No, AE does not mention Galilean relaitivity in the context you stated. I am referring to chapter 7 of "Relativity" poublished 10 years after the 1905 paper. Thje absurduity is the substitution of light motion fo the for the man's motion and then claiming that the expression Vle - Vte = Vlt was arrived at from measurements using the train as the inertial frame from which the measurments were made. This statement of yours is not the statement written by AE in "Relativity", chaptger 7.He says that the expression, Vle - Vte = Vlt, cannot be correct as Vlt is less than c, which AE asserts here, that as the laws governing the motion of light must be the same in all inertial frames, which he assert means that the speed of light must be measured the same in all inertial frames. This is the arbitrary ststement which AE asserted. The laws governing duck motion are the same in all inertrial frames, but this does not mean that the speed of a single duck must be measured the same in all inertial frames, only that the laws of physics be the same. You are jumping the gun on AE and SRT by assuming the validity of SRT, when AE has just made the statement that "speed measured the same" is equivalent to "the laws of motion being the same". Do you see the difference? I am using chapter 7, of "Relativity". Your statement that AE stated that "Electromagnetism would be inconsistent without special relativity" is jsut a statement, unproved in the original paper and unproved in "Relativity". It is a mere "Claim". Your statement is out of context with my statement that you are discussing, and that AE constructed. Remember, James R, and do not slide over the following: AE stated that the expression Vle - Vte = Vlt assumes (without explanation) and after his construction of the gedanken, clearly has the measurements taken from the embankment, where no error results. The expression is a simple statement showing how much faster is the speed of light than is the train speed, and that the measurements were made with the train as the measuring frame of reference, Explain this statement here please. We are still discussing Chapter 7 of "Relativity" and AE's discussion of the reasoning behind his 1905 paper, remember? I was clearly discussing the result when one assumes (erroneously) that the motion of light emitted perpendicular to the motion of the source has a velocity component of the moving source. I have no trouble distinguishing Galilean and Special Relativity. Keep on the topic of the post you are criticising. Here it is: AE stated that Vle - Vte = Vlt, and that as Vlt < Vle we must adjust for this inconsistency because the laws of motion of light must be the same in all inertial frames which means, according to AE arbitrarily, that the speed of light must be measured the same in all inertial frames, which is an absurdity. He cannot say that here as the expression was constructed from measurmenets made from the embankment and one cannot rationally use the expression Vlt as being measured from the train inertial frame of reference!!!!! You haven't come to grips with AE here James R. Just because one disagrees with SRT does not mean that person is ignorant of SRT. I know of many Nobel Laureates in physics that did not mention AE or SRT in their theisis from which their Nobel Prize was awarded. If you mean that "have never achieved anything of note" means "public fame and fortune, this means noithing regarding SRT. Disagreemnt does not mean misconception. From my perspective, you have misconcieved my discussion of AE, which means you have misconstrued AE as I have been quoting him extensively. Geistkiesel
You are in error. Light motion is independent of the motion of the source of the light. remember the "independence postulate" przyk? Geistkiesel
Yep. The speed of light is the same in all inertial frames in a vacuum, but this isn't necessarily true of it's component velocities. The component of the light's velocity perpendicular to the emitter's motion slows down due to time dilation. It's c*sqrt(1 - v<sup>2</sup>/c<sup>2</sup>), where v is the velocity of the emitter. I'm sure you can apply Pythagoras to check that the light's speed is c. The result is hardly surprising - the calculation is the exact opposite of the derivation of the time dilation formula found in many textbooks (and linked to in the physics subforum FAQ).
Sure, but then by definition you are not talking about SR. You cannot say "assume not(SR)" and then logically claim "therefore not(SR)". But then, logic has never been your strong point. -Dale
It sounds like he wrote that in anticipation that the reader will use her 'Galilean intuition' to understand that the Embankment is the rest frame, and the Train is the moving frame. He includes the words "the vacua" only to satisfy those who would complain that the speed of light in air is not c. But my point was that there is also a vacuum in the train frame. It does not seem correct to equate 'the vacua' with the embankment frame only. Consider the people riding along in the inertial train. (They wear scuba masks, I suppose.) For them, it is the embankment that is moving. The vacuum cannot be moving since it is nothingness in and of itself. So now the situation is exactly the same as it was in the Embankment frame in all respects, except that the names of the frames are reversed. Is there any logical reason that their vacuum is not as valid as the embankment's vacuum? A vacuum, being nothingness, is at rest in every inertial frame! :m: Your use of only the Galilean velocity-addition formula seems to be your own solution to the problem of 'equivalence of all inertial frames'. Your approach works fine as long as you give the Embankment frame a preferred status. I think if you went ahead into some of the subsequent chapters, you would find that the train frame is just as valid, and that passengers inside the train measure light-speed as c without having to subtract the velocity of the train. After all, for them, that would mean subtracting the speed of the embankment which is moving outside the train, and has nothing to do with c being a constant in their own frame.
geistkiesel: I don't see any point continuing this discussion. Your focus seems to restricted to one book of Einstein's, to the exclusion of all other writings by him or anybody else on the subject. You also ignore all experimental evidence which supports special relativity. Not having a copy of Einstein's book at hand, I cannot respond to your individual claims. I must assume that you have simply misinterpreted Einstein. This would not surprise me, since you have a history of misinterpreting scientific texts. Previously, I participated in a discussion with you about Feynman's Lectures on Physics, which you also muddled. I don't expect your understanding of Einstein to be any better. Without discussing Einstein's words, the originals of which I cannot check at present, I will restrict myself to your other comments: This is correct. However, light differs from ducks in that the Maxwell's equations dictate that the speed of light is constant. Since Maxwell's equations take the same forms in all frames, the constancy of the speed of light in all frames necessarily follows. Maxwell's equations say nothing about ducks. Take Einstein out of it. I state that electromagnetism is inconsistent without special relativity. Let's debate that, rather than what Einstein did or did not say. Perpendicular in whose frame? What is perpendicular emission in one frame will not be so in a different frame. But the statement Vle - Vte = Vlt is incorrect in special relativity, as you have admitted. End of discussion.
Then nature is absurd, because that's exactly what a century of experimentation has shown, to ever increasing accuracy. >>edit James: I have a copy of the book. It's not particularly good, either Einstein was a poor popular writer or it lost a lot in translation from German to English. It is written in as an attempt to explain Relativity to the "lay" public. Geist is badly misunderstanding the chapter. It is devoted to showing the incompatability of the Galilean transform with the constancy of the measured speed of light in all inertial frames. It uses the phrase "principle of relativity" numerous times in the Newtonian/Galilean sense of the invariance of physical law between inertial frames. Special relativity is only meantioned in the last paragraph.
