| Speed of light is relatively constant |
| Einstein said w=c-v which means the speed of light is additive to the speed of the speed of the selected frame of reference. In this section of the Theory of Relativity, it makes it clear that any point of reference is equally interchangeable. That means the theory of relativity says the speed of light is relative to the point of reference, either the train or the embankment. That means any discussion of relativity can equally use the train or the embankment as the moving or fixed point. QUOTE from the Theory of Relativity Appendix II. PART II THE GENERAL THEORY OF RELATIVITY SPECIAL AND GENERAL PRINCIPLE OF RELATIVITY The basal principle, which was the pivot of all our previous considerations, was the special principle of relativity, i.e. the principle of the physical relativity of all uniform motion. Let us once more analyze its meaning carefully. It was at all times clear that, from the point of view of the idea it conveys to us, every motion must be considered only as a relative motion. Returning to the illustration we have frequently used of the embankment and the railway carriage, we can express the fact of the motion here taking place in the following two forms, both of which are equally justifiable: (a) The carriage is in motion relative to the embankment, (b) The embankment is in motion relative to the carriage. In (a) the embankment, in (b) the carriage, serves as the body of reference in our statement of the motion taking place. If it is simply a question of detecting or of describing the motion involved, it is in principle immaterial to what reference-body we refer the motion . As already mentioned, this is self-evident, but it must not be confused with the much more comprehensive statement called "the principle of relativity," which we have taken as the basis of our investigations. The principle we have made use of not only maintains that we may equally well choose the carriage or the embankment as our reference-body for the description of any event (for this, too, is self-evident). Our principle rather asserts what follows : If we formulate the general laws of nature as they are obtained from experience, by making use of (a) the embankment as reference-body, (b) the railway carriage as reference-body, then these general laws of nature (e.g. the laws of mechanics or the law of the propagation of light in vacuo) have exactly the same form in both cases. This can also be expressed as follows : For the physical description of natural processes, neither of the reference bodies K, K1 is unique (lit. " specially marked out ") as compared with the other. Unlike the first, this latter statement need not of necessity hold a priori; it is not contained in the conceptions of " motion" and " reference-body " and derivable from them; only experience can decide as to its correctness or incorrectness. Up to the present, however, we have by no means maintained the equivalence of all bodies of reference K in connection with the formulation of natural laws. Our course was more on the following lines. In the first place, we started out from the assumption that there exists a reference-body K, whose condition of motion is such that the Galileian law holds with respect to it : A particle left to itself and sufficiently far removed from all other particles moves uniformly in a straight line. With reference to K (Galileian reference-body) the laws of nature were to be as simple as possible. But in addition to K, all bodies of reference K1 should be given preference in this sense, and they should be exactly equivalent to K for the formulation of natural laws, provided that they are in a state of uniform rectilinear and non-rotary motion with respect to K ; all these bodies of reference are to be regarded as Galileian reference-bodies. The validity of the principle of relativity was assumed only for these reference-bodies, but not for others (e.g. those possessing motion of a different kind). In this sense we speak of the special principle of relativity, or special theory of relativity. In contrast to this we wish to understand by the "general principle of relativity" the following statement : All bodies of reference K, K1, etc., are equivalent for the description of natural phenomena (formulation of the general laws of nature), whatever may be their state of motion. But before proceeding farther, it ought to be pointed out that this formulation must be replaced later by a more abstract one, for reasons which will become evident at a later stage EQUOTE from the Theory of Relativity This quote seems very clear. "the law of the propagation of light in vacuo) have exactly the same form in both cases" for either the embankment or the train. A typical animation that shows the light going toward the moving train observer is simply doing half of what Albert says. We need the second half showing the light going toward the moving ground observer. Remember: "we may equally well choose the carriage or the embankment as our reference-body for the description of any event". The next quote further supports that point. QUOTE from the Theory of Relativity THE RELATIVITY OF SIMULATAINEY When we say that the lightning strokes A and B are simultaneous with respect to be embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A arrow B of the embankment. But the events A and B also correspond to positions A and B on the train. EQUOTE from the Theory of Relativity The word “also” is very important. It re-enforces that A on both the train and ground correspond. Also, B on both the train and ground correspond. Most important, it means that M on both the ground and the train correspond. QUOTE from the Theory of Relativity PART I THE SPECIAL THEORY OF RELATIVITY THE PRINCIPLE OF RELATIVITY (IN THE RESTRICTED SENSE) If, relative to K, K1 is a uniformly moving co-ordinate system devoid of rotation, then natural phenomena run their course with respect to K1 according to exactly the same general laws as with respect to K. This statement is called the principle of relativity (in the restricted sense). The principle of relativity must therefore apply with great accuracy in the domain of mechanics. But that a principle of such broad generality should hold with such exactness in one domain of phenomena, and yet should be invalid for another, is a priori not very probable. EQUOTE from the Theory of relativity This is simply another way of saying the same thing as the first quote. QUOTE from the Theory of Relativity THE THEOREM OF THE ADDITION OF VELOCITIES EMPLOYED IN CLASSICAL MECHANICS As a consequence of his walking, however, he traverses an additional distance w relative to the carriage, and hence also relative to the embankment, in this second, the distance w being numerically equal to the velocity with which he is walking. Thus in total he covers the distance W=v+w relative to the embankment in the second considered. We shall see later that this result, which expresses the theorem of the addition of velocities employed in classical mechanics, cannot be maintained ; in other words, the law that we have just written down does not hold in reality. EQUOTE from the Theory of Relativity Here Albert is saying the speed of the man walking on the train both does and doesn't add to the distance he moves relative to the ground. Albert is saying W=v+w was correct but is not correct. In other words 2=1+1 changes from correct to not correct. He does that by making time and space meaningless. QUOTE from the Theory of Relativity THE APPARENT INCOMPATIBILITY OF THE LAW OF PROPAGATION OF LIGHT WITH THE PRINCIPLE OF RELATIVITY The velocity w of the man relative to the embankment is here replaced by the velocity of light relative to the embankment. w is the required velocity of light with respect to the carriage, and we have w = c-v. The velocity of propagation of a ray of light relative to the carriage thus comes out smaller than c. But this result comes into conflict with the principle of relativity set forth in Section V. For, like every other general law of nature, the law of the transmission of light in vacuo [in vacuum] must, according to the principle of relativity, be the same for the railway carriage as reference-body as when the rails are the body of reference. But, from our above consideration, this would appear to be impossible. If every ray of light is propagated relative to the embankment with the velocity c, then for this reason it would appear that another law of propagation of light must necessarily hold with respect to the carriage -- a result contradictory to the principle of relativity. In view of this dilemma there appears to be nothing else for it than to abandon either the principle of relativity or the simple law of the propagation of light in vacuo. Those of you who have carefully followed the preceding discussion are almost sure to expect that we should retain the principle of relativity, which appeals so convincingly to the intellect because it is so natural and simple. The law of the propagation of light in vacuo would then have to be replaced by a more complicated law conformable to the principle of relativity. The development of theoretical physics shows, however, that we cannot pursue this course. The epoch making theoretical investigations of H. A. Lorentz on the electrodynamic and optical phenomena connected with moving bodies show that experience in this domain leads conclusively to a theory of electromagnetic phenomena, of which the law of the constancy of the velocity of light in vacuo is a necessary consequence. Prominent theoretical physicists were therefore more inclined to reject the principle of relativity, EQUOTE from the Theory of Relativity This section caused a big problem for Einstein when he said w=c-v. Their problem also applies for others who think w=c-v as Einstein says. If you agree with Einstein who said w=c-v, you think the speed of light is additive (relative) to the speed of the train. If you think w=c-v is wrong, then you disagree with Einstein. QUOTE from the Theory of Relativity ON THE IDEA OF TIME IN PHYSICS Lightning has struck the rails on our railway embankment at two places A and B far distant from each other. I make the additional assertion that these two lightning flashes occurred simultaneously. EQUOTE from the Theory of Relativity This quote is important to establish that we are in fact discussing real simultaneous events. There is no question about perception, they are simultaneous events. QUOTE from the Theory of Relativity We encounter the same difficulty with all physical statements in which the conception "simultaneous" plays a part. The concept does not exist for the physicist until he has the possibility of discovering whether or not it is fulfilled in an actual case. We thus require a definition of simultaneity such that this definition supplies us with the method by means of which, in the present case, he can decide by experiment whether or not both the lightning strokes occurred simultaneously. As long as this requirement is not satisfied, I allow myself to be deceived as a physicist (and of course the same applies if I am not a physicist), when I imagine that I am able to attach a meaning to the statement of simultaneity. (I would ask the reader not to proceed farther until he is fully convinced on this point.) EQUOTE from the Theory of Relativity This is an important quote because Albert talks about experiments and discovering fact about the actual case. He is talking using real data to prevent being deceived. Another key part of this statement is how it addresses the confirmation that simultaneous are really simultaneous. There is no question that things look different from different perspectives. Perspective is not the question yet. The question Albert raised is about attaching a meaning to the statement of simultaneous events. It is only later that Albert changes the search for meaning of simultaneous to a search for perception from different locations. QUOTE from the Theory of Relativity I am very pleased with this suggestion, but for all that I cannot regard the matter as quite settled, because I feel constrained to raise the following objection: "Your definition would certainly be right, if only I knew that the light by means of which the observer at M perceives the lightning flashes travels along the length A arrow M with the same velocity as along the length B arrow M. But an examination of this supposition would only be possible if we already had at our disposal the means of measuring time. EQUOTE from the Theory of Relativity Here Albert is specifically disputing the speed of light being constant. Albert specifically calls the velocity of light into question. The Michelson and Morley experiment shows that the direction of travel does not change the velocity of light. This is one of the most blatant examples of Albert contradicting Albert. Then magically the meaning of time comes to the rescue when searching for experimental verification that two events are simultaneous. QUOTE from the Theory of Relativity THE RELATIVITY OF SIMULATAINEY People traveling in this train will with a vantage view the train as a rigid reference-body (co-ordinate system); they regard all events in Fig. 01: file fig01.gif reference to the train. Then every event which takes place along the line also takes place at a particular point of the train. Also the definition of simultaneity can be given relative to the train in exactly the same way as with respect to the embankment. As a natural consequence, however, the following question arises : Are two events (e.g. the two strokes of lightning A and B) which are simultaneous with reference to the railway embankment also simultaneous relatively to the train? We shall show directly that the answer must be in the negative. When we say that the lightning strokes A and B are simultaneous with respect to be embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A arrow B of the embankment. But the events A and B also correspond to positions A and B on the train. EQUOTE from the Theory of Relativity Here Albert says that A and B on the ground correspond to A and B on the train. Then Albert says that the mid point for A and B is not the same mid point for A and B. This is self contradictory. Since the A and B points are corresponding points on the train and the ground, then M and M are corresponding points on the train and the ground. Earlier we saw Albert question the constant velocity of light. Now in one paragraph, we see Albert introduce self contradictory conditions in his own thought experiment. We are supposed to believe that: A corresponds to A B corresponds to B M corresponds to M Then, A, B and M become A1 B1 and M1. Then M1 does not correspond to M. This is when Albert changes the question from attaching a meaning to the term simultaneous to a philosophical search for how to deal how things look from different perspectives. QUOTE from the Theory of Relativity Let M1 be the mid-point of the distance A arrow B on the traveling train. Just when the flashes (as judged from the embankment) of lightning occur, this point M1 naturally coincides with the point M but it moves towards the right in the diagram with the velocity v of the train. If an observer sitting in the position M1 in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A. Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A. We thus arrive at the important result: EQUOTE from the Theory of Relativity For a moment, M and M1 coincide. Then M1 does not coincide with M because M1 moved from M. Now sure, we all know that M1 is moving relative to M. However; M is also moving to M1. Remember all of the stuff about them being relative. So, what ever is fair for M is also fair for M1. The animation showing M1 moving is only showing half the relativity picture. Further, their movement does not change the meaning of simultaneous. Their movement changes the perspective of the uninformed observer. QUOTE from the Theory of Relativity Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train, and vice versa (relativity of simultaneity). EQUOTE from the Theory of Relativity Here the key words are vice versa (relativity of simultaneity). I can make a few changes to the statement to make it correct. The way I say it is: Events which appear to be simultaneous with reference to the embankment do not appear to be simultaneous with respect to the train, and vice versa (relativity of simultaneity perception). Albert did not call it perception or appearance, he called it a new reality that makes time and space meaningless. Summary: What are some of the things Albert says that are of concern or contradictory? Albert says: W=v+w WHERE: W (man’s ground velocity) = v (train velocity) + w (man’s train velocity) This formula says the speed of the man and the train are additive relative to get his ground speed. w (man’s train velocity becomes light’s train velocity) w = c-v WHERE: w (light’s train velocity) = c ( c ) - v ( train) This formula says the required speed of c relative to the train is c minus the speed of the train. To deal with this problem, he makes time and space meaningless. Albert says A and B are the same relative to the ground and the train even though the ground and the train move relative to each other. Albert says both M on the ground and the train correspond but they do not continue to correspond. Albert questions the meaning of simultaneous. The answer is simple: occurring or done at the same time. Albert specified that the events are simultaneous then he proceeds to deal with the perception of simultaneous events from different perspectives. If Albert were to say the perception of the speed of light changes by simply changing the perception of the observer, he would be correct. The meaning of perception is: a way of understanding or interpreting something. Albert questioned the constant velocity of light. Then he uses that question to proceed with diverting to the meaning of simultaneous and how perspective changes perception. According to Albert, either the ground moves or the train moves causing the observers to not observe simultaneous arrival of the light. Sure, the light will not arrive simultaneously, one of the people moved. That is OK with Albert because the time and space become meaningless. This is what Albert says and some people still believe it after they have been informed. The reality is: A - If the light pulses occurred on the ground, they do not remain equal distance from the mid point of the train because the train moved relative to lightning strikes. B - If the light pulses occurred in both the train and ground frames, they are relative to both frames and will travel at the speed of light inside both frames. Copyright © 2007 2008 Don Edward Sprague. All rights reserved. |
In Einstein relativity, observers in each frame uses different conditions for the same events. That is: - The earth observer says the train observer moved between the lights. - The train observer says the earth observer moved between the lights. In Classical Mechanics and Classical hierarchy Relativity: - Both observers say the train observer moved between the lights. The laws of physics can’t be the same in all frames and also allow the conditions for events to be different in each frame. - The Lorentz transformation gives infinite different values across frames. - The Galilean Transformation gives 100% same conditions across frames. The words and concept are clear. Einstein says: “As long as it is moving uniformly, the occupant of the carriage is not sensible of its motion, and it is for this reason that he can unreluctantly interpret the facts of the case as indicating that the carriage is at rest, but the embankment in motion." The concept Einstein advances is that the train observer can be fooled as long as the train is moving smooth enough. He overlooks the concept that the being fooled doesn’t transform to reality. He claims to switch an observer who is not sensible of its motion to become an observer who isn’t moving. An illusion isn’t a basis for variable time. The laws of physics are the same in all frame all the time. Any observer in any frame might be able to determine the motion of the frame from within the frame. People on earth where able to prove the earth isn't flat and it is moving around the sun and the sun is moving and so on. Classical hierarchy Relativity is based on Classical Mechanics. The only thing that supposedly causes a problem for CM and ChR is Lorentz contraction-Contradiction and Einstein relativity. Since they are wrong, then there is no problem with CM and ChR. Copyright Don E. Sprague 2011 |