studiot Posted September 15, 2014 Posted September 15, 2014 (edited) I cannot see what you are getting at, this is probably why my answer was not satisfying to you, but I still don't, so I guess you will not like this answer either. For the purpose of my thesis Your thesis? This is a discussion forum. I did not understand what you were posting so I asked for more information. That is the way discussion works. By contrast you say (now) that you did not understand what I said (fair enough) but you did not ask for more information, but instead made dismssive comments using 'my thesis', to ploughi on as if I had made no comment at all. Edited September 15, 2014 by studiot
christopherkirkreves Posted September 15, 2014 Author Posted September 15, 2014 xyzt said: “Good, Continue to waste your time. I am through trying to educate you.” You and I totally disagree. I believe that to try to disprove myself (or anyone else) is not a waste of time. Every day I ask the question over and over again “Do I know what I think I know.” And apparently you don’t believe in this same approach to life. That’s cool. ---- swansont said: “On must ask where an observer is when each bolt strikes, and where that observer is when the light reaches him/her, and that depends on the presence of relative motion. If the bolts do not travel the same distance, then the strikes can't be observed to be simultaneous.” This is the crux of the issue. If the man on the train is correct in thinking he is at rest (as Einstein says he is), then this observer [the man on the train] is at the midpoint between the two sources of light when they flashed and he will remain at this point and so he will see them simultaneously; because the two flashes of light have traveled the same distances at the same velocity to him. And so, in this thought experiment, if both men are correct in thinking that they are the one at rest (which Einstein says they are) then they will both see the two flashes of light simultaneously. And so, this thought experiment does not prove that “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” (But Comstock’s does.) “It's not. The premise is that SR is correct. The investigation is whether events are simultaneous, but the status is not assumed.” When I read the book “Relativity: The Special and General Theory” it is clear to me that Einstein is building up the Theory of Relativity proof by proof and all resting on the initial proof of “the relativity of simultaneity.” But that’s just my impression of what he is doing. However, in the same year he published this book for the masses, 1916, he also published a scholarly article for the elite (not me) titled “The Foundation of the General Theory of Relativity.” And the third paragraph reads as follows: “Thus the special theory of relativity does not depart from classical mechanics through the postulate of relativity, but through the postulate of the constancy of the velocity of light in vacuo, from which, in combination with the special principle of relativity, there follow, in the well-known way, the relativity of simultaneity, the Lorentzian transformation, and the related laws for the behavior of moving bodies and clocks.” (see A. Einstein, "Die Grundlage der allgemeinen Relativitatsheorie," Annalen der Physik, 49, 1916.) (Please note, the “principle of relativity” is not the same thing as the “theory of relativity” and the former is explained in chapter 5 of his book.) In his book he builds his theory, proof by proof, based on the initial proof of the “Two Lightning Bolt Strikes” thought experiment. Not on the Lorentz transformations or anything else. He does this, but he does not actually come out and say “I’m build my theory on the “Two Lighting Bolt Strikes” thought experiment proving the “Relativity of Simultaneity.”” But, in that same year, 1916, in a different publication he does come out say this is what he is doing. In that quote is saying that the Special Theory of Relativity rests on two postulates: 1. The constancy of the velocity of light, and 2. The special principle of relativity And then he says “… there follow, in the well-known way …” He is saying what comes next in his theoretical structure of proof based proof and what he fist lists (after laying out the postulates) is: “the relativity of simultaneity” and then immediately after this (just does he does in his book) he lists: “the Lorentzian transformations” and then (again just as he does in his book) the ramifications of the Lorentz transformations “and the related laws for the behavior of moving bodies and clocks” (ie, “length contraction” and “time dilation”) And so you and I disagree. I think it is circular logic, when investigating whether or not the flashes of light are simultaneous, to take “events which are simultaneous in one inertial frame of reference are not in another” as a premise. I do not believe Einstein used this as a premise. I think he thought he made his case without this as a premise (as Comstock six years earlier had done). Thank you. -------- To studiot: I do want to have a wider discussion (not just about all of the Special Theory of Relativity, but also about the General Theory of Relativity). But, I was wrong in thinking that it would be totally obvious that the “Two Lighting Bolt Strikes” thought experiment does not work and we could more quickly move onto other things. But, I don’t mind. We can spend as much time on just this one aspect of this theory, on just this one thought experiment, for as long as is needed. Okay. In five lines? 1. Einstein says (and I agree with him) that the man on the train can consider himself to be at rest. 2. Einstein stipulates that the two flashes of light occur at the same time and at the same distance from the man on the train. 3. The motion, or lack of motion, of the emanating sources of the flashes light (the points of impact) are irrelevant. 4. And so, with the two flashes of light occurring (as stipulated) at the same time and then traveling at equal velocities over equal distances to the man on the train (who is justifiably “at rest”) he will then see the two flashes of light at the same time. 5. And so, this thought experiment does not prove that the man on the embankment will see the two flashes of light at the same time while the man on the train will see the one flash of light before the other. And if I’m allowed one more line (and, here again, I’m repeating myself but it seems somewhat necessary): 6. It is the conclusion of this thought experiment that “events which are simultaneous in one inertial frame of reference are not simultaneous in another and therefore every inertial frame of reference has its own particular time” and to address my five lines above by saying that this is not just the conclusion of this thought experiment but also a premise, I believe, is to engage in circular logic. Thank you. -------- To pzkpfw: In 1910 D.F. Comstock proposed the “One Light Bulb in a Moving Car” thought experiment. Given these four axioms: One. There is no absolute rest. Two. The velocity of light is independent of the motion of the emanating source. Three. The velocity of light is invariant for all observers. Four. The law of physics hold true (are the same) in all inertial frames of reference. This proves (in the sense of a thought experiment) “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” Comstock proves the relativity of simultaneity. And this is done without the mathematics of the Lorentz transformations, this is done without any reference to “time dilation” or “length contraction,” and this is done without any ambiguity over for whom the two events are simultaneous and for whom one will occur before the other and therefore a stipulation is needed. The man in the car will see the two flashes of light reach the front and rear of the car simultaneously and the man on the road will see the one flash of light reach the rear of the car first and then the other flash of light reach the front of the car later. I believe Einstein, six year later, in his “Two Lightning Bolt Strikes” thought experiment, was attempting to prove the same thing Comstock proved in his “One Light Bulb In a Moving Car” thought experiment. And I believe he failed. I understand your argument. And while I don’t agree with you I must admit it is a plausible argument. When Einstein says “We shall show directly that the answer must be in the negative” (me quoting you quoting him) I believe he is saying that just as Comstock did show that the man in the car must see the two flashes of light reach the front and the rear of the car simultaneously and the man on the road must see the one flash of light reach the rear of the car first then the other flash of light reach the front of the car later, so too will he, Einstein, show in his “Two Lightning Bolt Strikes” thought experiment that the man on the embankment must see the two flashes of light simultaneously while the man on the train must see the one flash of light before the other. But, of course, I have to admit that your reading of his language is plausible. I have to admit that maybe Einstein is not attempting to do what Comstock did six years earlier. I have to admit that maybe Einstein is saying that it could be the man on the embankment or it could be the man on the train who see the two flashes of light simultaneously and then therefore logic dictates that since other guy is in a different position he can’t also see them simultaneously. Yep. Okay. So, then I have two question/comments for you. One. If Einstein is doing what you say he is doing, then, while his thought experiment does work, it is a much weaker thought experiment than Comstock’s. Comstock proves “events which are simultaneous in one inertial frame of reference are not simultaneous in another” without any ambiguity over who sees them simultaneously and who does not. If Einstein thought experiment works as you say it does, why use it and not the much stronger thought experiment that was well known at the time (1916) and that had been around for six years (since 1910)? Two. While “thought experiments” cannot “prove” what actually physically happens in the real world, they are supposed to “demonstrate” or “describe” what does happen in the real world. In other words, while the “Two Lightning Bolt Strikes” cannot “prove” that “events which are simultaneous in one inertial frame of reference are not simultaneous in another” is in fact what happens in the real physical world, it is intended to “show” that this is in fact what does happen in this real physical world. This thought experiment cannot “prove” this is true, but this thought experiment is saying essentially “yeah, this is how the real physical world does work.” Okay. If you agree with me so far, then here is my point: So, if in the real physical world there was a real physical man on a train and a real physical man on an embankment and there were two real physical flashes of light an equal distance from them that occurred at the same time, then (again, noting that this thought experiment did not prove anything) this thought experiment is telling us that one of the men will see the two flashes of light simultaneously while the other man will see the one flash of light before the other. Yes? And so, if you’re right and it’s a matter of stipulation about who sees them simultaneously and who sees one before the other, then in a sense we are playing “God.” In this thought experiment either you or I or Einstein steps in and says the man on the train or the man on the embankment is the one who sees them simultaneously. But, in the real physical world, you and I and Einstein, do not have this power. And so, if you and I agree that both the man on the embankment and the man on the train are equally positioned to see the two flashes of light at the same time, and if one of them does and the other does not, then in the real physical world, “God” must step in and take the place of you and I and Einstein and do the stipulating in the real physical world and decide who, the man on the train or the man on the embankment, sees the flashes of light simultaneously and who does not. But, in Comstock’s thought experiment there is no need for a “God.” In the world of thought experiments it is the man in the car who sees them reach the front and the rear of the car simultaneously and the man on the road who sees the one flash of light reach the rear of the car first and then the other flash of light reach the front of the car later. And if this same situation was to occur in the real physical world then then, while this thought experiment cannot prove this will happen, this thought experiment shows (or demonstrates) that this will happen in the real physical world without “God” having to step in an make the determination (stipulation). No? Thank you. ------ To Le Repteux: I’m not ignoring you, but as you can see my two hours of internet time at the public library is already taking up with a more basic discussion. What you are talking about, for me, is a much later discussion. Thank you. - Christopher (ps as always, sorry for the typos)
xyzt Posted September 15, 2014 Posted September 15, 2014 xyzt said: “Good, Continue to waste your time. I am through trying to educate you.” You and I totally disagree. I believe that to try to disprove myself (or anyone else) is not a waste of time. I already disproved your fringe ideas. That was not a waste of time. The waste of time is that you won't admit that your ideas were disproved and that you will continue forever to re-assert the same crankery. That is a waste of everybody's time.
studiot Posted September 15, 2014 Posted September 15, 2014 Christopher, Einstein's description has rather more hidden depths than perhaps you have given him credit for. It avoids the obvious trap that Robin's proposed alternative experiment falls into and that Le Repteux (rightly) objects to. Namely that you do not and should not try to arrange an experiment that requires a trigger, since information cannot travel faster than c. Einstein does not (as far as I am aware) explicity state this, but what he does state circumvents the issue in two ways. The reader is meant to work these out for himself. Firstly the lightning event is a chance event and by chance, happens just right for the experiment. Secondly matters can be confirmed at leisure post event.That is both the positions of the observers and strikes can be measured subsequently. Now ask yourself where does the lightning come from? Does it come from a universe moving alongside the train? Or does it come from the universe where the track is sited? Or does it come from another universe altogether? Please ask any questions you need to clarify my comments and answer the question (three choices) I have asked at the end. Using that answer I can explain Einstein's train experiment to you.
Le Repteux Posted September 15, 2014 Posted September 15, 2014 Your thesis? This is a discussion forum. I did not understand what you were posting so I asked for more information. That is the way discussion works. By contrast you say (now) that you did not understand what I said (fair enough) but you did not ask for more information, but instead made dismssive comments using 'my thesis', to ploughi on as if I had made no comment at all. I did ask for more information, I asked you to enumerate the principles that you wanted me to comment, but I still do not see what you want to do with that information.
pzkpfw Posted September 15, 2014 Posted September 15, 2014 (edited) In 1910 D.F. Comstock proposed the “One Light Bulb in a Moving Car” thought experiment. ... This proves (in the sense of a thought experiment) “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” Comstock proves the relativity of simultaneity. And this is done without the mathematics of the Lorentz transformations, this is done without any reference to “time dilation” or “length contraction,” and this is done without any ambiguity over for whom the two events are simultaneous and for whom one will occur before the other and therefore a stipulation is needed. Well, I don't think there's any need for lorentz, time dilation or length contraction in Einsteins version either. Nor do I think there's any ambiguity. The man in the car will see the two flashes of light reach the front and rear of the car simultaneously and the man on the road will see the one flash of light reach the rear of the car first and then the other flash of light reach the front of the car later. That setup and stipulations are no different really (in the sense of setupishness and stipulationity) than the Einstein version. The setup by comstock ensures the flashes are simultaneous in the car frame, and shows they won't be for the bystander. Einstein sets up the embankment frame to have simultaneous flashes and shows they won't be simultaneous for the other observer. I believe Einstein, six year later, in his “Two Lightning Bolt Strikes” thought experiment, was attempting to prove the same thing Comstock proved in his “One Light Bulb In a Moving Car” thought experiment. And I believe he failed. Well, I think he succeeded. It's easy to come up with ways section 9 could have been improved, but it stands alone. I understand your argument. And while I don’t agree with you I must admit it is a plausible argument. When Einstein says “We shall show directly that the answer must be in the negative” (me quoting you quoting him) I believe he is saying that just as Comstock did show that the man in the car must see the two flashes of light reach the front and the rear of the car simultaneously and the man on the road must see the one flash of light reach the rear of the car first then the other flash of light reach the front of the car later, so too will he, Einstein, show in his “Two Lightning Bolt Strikes” thought experiment that the man on the embankment must see the two flashes of light simultaneously while the man on the train must see the one flash of light before the other. More or less. But: depending on the setup, and which frames the flashes are simultaneous in. Comstock set it up so the flashes will be simultaneous in the car frame, by placing the bulb in the centre of the car. Einstein stipulates the strikes to be simultaneous in the embankment frame. It's basically the same thing. The real point is - what now is the situation for the other frame? But, of course, I have to admit that your reading of his language is plausible. I have to admit that maybe Einstein is not attempting to do what Comstock did six years earlier. I have to admit that maybe Einstein is saying that it could be the man on the embankment or it could be the man on the train who see the two flashes of light simultaneously and then therefore logic dictates that since other guy is in a different position he can’t also see them simultaneously. Aside from you seeming to contradict yourself (because the end result is the same but you claim different interpretations) that's where the Comstock experiment falls down, it doesn't show the reciprical nature of the relativity of simultaneity very well. Okay. So, then I have two question/comments for you. One. If Einstein is doing what you say he is doing, then, while his thought experiment does work, it is a much weaker thought experiment than Comstock’s. Comstock proves “events which are simultaneous in one inertial frame of reference are not simultaneous in another” without any ambiguity over who sees them simultaneously and who does not. I really don't see why you are so hung up on that claimed "ambiguity". Comstock made the flashes simultaneous for one observer. Einstein stipulated them to be for one observer. Meh! If Einstein thought experiment works as you say it does, why use it and not the much stronger thought experiment that was well known at the time (1916) and that had been around for six years (since 1910)? I don't think Comstocks is stronger. Here you are assuming your opinion to be universal. I don't think Comstock shows recpricity well. And, given neither of his observers are equidistant from the ends of the carriage (going by your diagram) then they both need to use distance and speed of light to figure out if the flashes were simultaneous (in their frame). Einstein does that better by having both of his observers equidistant from the strikes. Two. ... So, if in the real physical world there was a real physical man on a train and a real physical man on an embankment and there were two real physical flashes of light an equal distance from them that occurred at the same time, ... Given you seem to accept Comstocks result, why do you phrase this as "that occurred at the same time" without reference to which frame they occured at the same time in? This where it seems you seem to assume absoluteness of simultaneity - and then get consfused by the results of the experiment! ... then (again, noting that this thought experiment did not prove anything) this thought experiment is telling us that one of the men will see the two flashes of light simultaneously while the other man will see the one flash of light before the other. Yes? In the given scenario, yes. And so, if you’re right and it’s a matter of stipulation about who sees them simultaneously and who sees one before the other, then in a sense we are playing “God.” In this thought experiment either you or I or Einstein steps in and says the man on the train or the man on the embankment is the one who sees them simultaneously. But, in the real physical world, you and I and Einstein, do not have this power. Well, that's basically getting to be metaphysical rubbish. Strikes are either going to be simultaneous in a frame or not. There's no "God power" involved in looking at a case where two strikes were simultaneous in one frame and figuring out whether they were in another. No more than Comstock is "God" with his light bulb placement. Let's have a thought experiment where a rock lands on my head, the question is: did the rock land on your head? We don't need to "play God" to say no. The rock just happened to land on my head not yours, whether in a thought experiment or in reality. And so, if you and I agree that both the man on the embankment and the man on the train are equally positioned to see the two flashes of light at the same time, ... If the flashes were simultaneous in their frame. (You continue to assume that simultaneous events must be simultaneous in all frames. (You show this in your 5(6) points reply to Studiot). You then deny the results of this thought experiment based on that assumption. It's your thinking that's circular. The experiment is much more fair than you. It simply chooses events which do happen to be simultaneous in one frame, and asks are they also simultaneous in the other frame? It doesn't assume they are not in the other (that would be circular), it shows they can't be.) ... and if one of them does and the other does not, then in the real physical world, “God” must step in and take the place of you and I and Einstein and do the stipulating in the real physical world and decide who, the man on the train or the man on the embankment, sees the flashes of light simultaneously and who does not. ... No. All your "God stuff" totally misses the point. Can events be simultaneous? (Would you really say no?) Well, then lets take the case where they were simultaneous in frame A. Either you are going to demand that they were also simultaneous in all other frames, or, you can figure out if they would be simultaneous in those other frames. Same as Comstock did. I think I'm sitting still. An observer sitting still on Mars might think I'm moving very fast. Who is right? Do we need some "God" to step in and say who is right? Edited September 16, 2014 by pzkpfw 1
swansont Posted September 15, 2014 Posted September 15, 2014 If the man on the train is correct in thinking he is at rest (as Einstein says he is), then this observer [the man on the train] is at the midpoint between the two sources of light when they flashed and he will remain at this point and so he will see them simultaneously; because the two flashes of light have traveled the same distances at the same velocity to him. And so, in this thought experiment, if both men are correct in thinking that they are the one at rest (which Einstein says they are) then they will both see the two flashes of light simultaneously. And so, this thought experiment does not prove that “events which are simultaneous in one inertial frame of reference are not simultaneous in another.” The example has two parts: that in the embankment frame the strikes are simultaneous, and also take place at specific positions — the front and back of the train, aligned with marks on the ground. In the train's frame the front and back don't (can't) simultaneously align with those marks, owing to length contraction. The observers can't disagree on where the strikes hit, since the train and the ground mark are co-located, and the distance between the marks will be shorter than the train in the train's frame.
Dekan Posted September 15, 2014 Posted September 15, 2014 If we can work out the answers by doing "Thought Experiments" , why bother with any actual physical tests? Couldn't we just program our thoughts into a computer simulation, run it, then write down what it says.
studiot Posted September 15, 2014 Posted September 15, 2014 Le Repteux I asked you to enumerate the principles that you wanted me to comment So why didn't you comment then? I only offered two principles.
Janus Posted September 15, 2014 Posted September 15, 2014 If we can work out the answers by doing "Thought Experiments" , why bother with any actual physical tests? Couldn't we just program our thoughts into a computer simulation, run it, then write down what it says. A thought experiment is only as good as the postulates it is built from. The only way to determine if those postulates actually apply to the real world is to perform a physical test to see if what the thought experiment predicts confirms to physical reality. 1
studiot Posted September 15, 2014 Posted September 15, 2014 This thread is going nowhere at approximately 0.99999999999c because no one seems to want to stick to the point and complete discussion of the first proposed 'experiment', rather prefering to introduce alternative experiments. Comstocks experiment or Einsteins? I could just as easily observe that Einstein introduced the formula E = mc2 in 1905, some 24 years after JJ Thompson introduced the formula E = 0.75melmc2
xyzt Posted September 15, 2014 Posted September 15, 2014 If we can work out the answers by doing "Thought Experiments" , why bother with any actual physical tests? Couldn't we just program our thoughts into a computer simulation, run it, then write down what it says. Absolutely, that's the ticket.
Le Repteux Posted September 16, 2014 Posted September 16, 2014 By fundamental I was thinking principles like:- The assumption that Space is isotropic (or not) The assumption that Space is homogeneous (or not) I can't see how measuring things with light or not measuring them this way is relevent or more fundamental. Studiot, Yes, until the small steps are established, I take for granted that space is isotropic and homogeneous for two atoms using light as a guide to execute them. Does that help you to accept them as a possibility?
xyzt Posted September 16, 2014 Posted September 16, 2014 Studiot, Yes, until the small steps are established, I take for granted that space is isotropic and homogeneous for two atoms using light as a guide to execute them. Does that help you to accept them as a possibility? No, it doesn't, you are still trying to pass word salads as science.
studiot Posted September 16, 2014 Posted September 16, 2014 (edited) Yes, until the small steps are established, I take for granted that space is isotropic and homogeneous for two atoms using light as a guide to execute them. Does that help you to accept them as a possibility? I don't know, because I'm not quite sure what you mean. Why do you need to qualify what you 'take for granted'? Incidentally did you read this comment I made to Christopher including a reference to your own posts? Christopher, Einstein's description has rather more hidden depths than perhaps you have given him credit for. It avoids the obvious trap that Robin's proposed alternative experiment falls into and that Le Repteux (rightly) objects to. Namely that you do not and should not try to arrange an experiment that requires a trigger, since information cannot travel faster than c Edited September 16, 2014 by studiot
Le Repteux Posted September 16, 2014 Posted September 16, 2014 (edited) Why do you need to qualify what you 'take for granted'? Because these properties of space usually concern macroscopic scales. Incidentally did you read this comment I made to Christopher including a reference to your own posts? Yes I did. And since virtual photons cannot exceed the speed of light, do you agree that this limit has to apply to the way atoms will measure their reciprocal motion when part of a molecule? Edited September 16, 2014 by Le Repteux
studiot Posted September 16, 2014 Posted September 16, 2014 Yes I did. And since virtual photons cannot exceed the speed of light, do you agree that this limit has to apply to the way atoms will measure their reciprocal motion when part of a molecule? Quite frankly I don't see the relevance to the topic of this thread. Because these properties of space usually concern macroscopic scales. Again I can't see the relevance of scale, although SR acts macroscopic scales. Further if it is fundamental it doesn't matter whether it is a usual or unusual application does it? You seem to be dancing away from the point and I don't know why since I am not disagreeing with you (not agreeing either) I'm only trying to clarify. You may like to know that the two properties I listed are considered equivalent to Einsteins first SR postulate.
Le Repteux Posted September 16, 2014 Posted September 16, 2014 (edited) Quite frankly I don't see the relevance to the topic of this thread. It is relevant if we consider that a mind experiment with two atoms and their background would be equivalent to the mind experiment with the train and its embankment. You may like to know that the two properties I listed are considered equivalent to Einsteins first SR postulate. Ah, this is probably where you were getting at. Of course, I knew about that equivalence, but I probably do not know it in detail as you may do. I know about all the main principles, but I learn the details when I need them, which is mainly to answer to objections about my ideas not corresponding to the actual theories. Instead of trying to understand others' ideas, we too often oppose them our own ones, because we cannot believe instantly to what is new, which is a good thing, otherwise there would be no evolution since there would be no resistance to evolution, thus no continuity. Did you have a look at this other subject of mine on mass? Does it interest you? http://www.scienceforums.net/topic/83590-look-ma-no-maths/ What about this other one on mind? http://www.scienceforums.net/topic/83736-look-ma-no-mind/ Edited September 16, 2014 by Le Repteux
xyzt Posted September 16, 2014 Posted September 16, 2014 It is relevant if we consider that a mind experiment with two atoms and their background would be equivalent to the mind experiment with the train and its embankment. There is no connection between the two cases. You are simply making up stuff.
studiot Posted September 16, 2014 Posted September 16, 2014 (edited) It is relevant if we consider that a mind experiment with two atoms and their background would be equivalent to the mind experiment with the train and its embankment. I have already noted that this thread is chasing its tail because folks keep proposing alternative experiments before concluding the one in hand. If you wish to discuss Einstein's train then fine. Edited September 16, 2014 by studiot
Phi for All Posted September 16, 2014 Posted September 16, 2014 Instead of trying to understand others' ideas, we too often oppose them our own ones, because we cannot believe instantly to what is new, which is a good thing, otherwise there would be no evolution since there would be no resistance to evolution, thus no continuity. ! Moderator Note ?! Did you have a look at this other subject of mine on mass? Does it interest you?http://www.scienceforums.net/topic/83590-look-ma-no-maths/ What about this other one on mind? http://www.scienceforums.net/topic/83736-look-ma-no-mind/ ! Moderator Note Please don't use one thread to advertise others. Also, people in this discussion are asking you to please focus on one subject at a time. And tossing words together to describe your ideas isn't helping you communicate them any better either. Please remember discussion requires that you be understood.
Le Repteux Posted September 17, 2014 Posted September 17, 2014 Hi Phy, How much for the publicity you just gave me? (Thats a joke! I got the message, which is very easy to understand by the way, compared to mine!) There is no connection between the two cases. You are simply making up stuff. I am trying to make up a point to begin with, the stuff around it will come later when you decide to feed it. Take two synchronized atomic clocks, put them at the two ends of the train, and let the two observers measure their frequencies: there will be no doppler effect for the observer on the train, but there will be some for the observer on the embankment. Do the contrary, put the two atomic clocks on the embankment: there will be no doppler effect for the observer on the embankment and some for the observer on the train. You see, when we only observe the frequencies, there is no contradiction. But the only way to produce precise frequencies at different places is to use synchronized atoms, and we can do so because we discovered that atoms stay synchronized. Now, if we can observe that atoms are synchronized, don't you think that atoms themselves already can? And if we can use that property of them, as for using the Positioning System to move precisely from one point to another for example, don't you think that they also could if the could move by themselves? For example, how do you think that the atoms of the moon can accelerate towards those of the earth so precisely that, from second to second, they compensate exactly for their orbital velocity? How could they do that without using their own timing system?
xyzt Posted September 17, 2014 Posted September 17, 2014 (edited) Take two synchronized atomic clocks, put them at the two ends of the train, and let the two observers measure their frequencies: there will be no doppler effect for the observer on the train, but there will be some for the observer on the embankment. Nope. You keep repeating the same mistake over and over. I will not explain why, I already did, i will just point out that you keep repeating the same mistake. Do the contrary, put the two atomic clocks on the embankment: there will be no doppler effect for the observer on the embankment and some for the observer on the train. Also nope. Edited September 17, 2014 by xyzt
studiot Posted September 17, 2014 Posted September 17, 2014 Le Repteux, Atomic or other clocks are irrelevent. Time measurement is not needed in Einstein's train experiment. So if we can stick to the original experiment details please, I will make the same offer I made to Robin in post#79 Now ask yourself where does the lightning come from? Does it come from a universe moving alongside the train? Or does it come from the universe where the track is sited? Or does it come from another universe altogether? Please ask any questions you need to clarify my comments and answer the question (three choices) I have asked at the end. Using that answer I can explain Einstein's train experiment to you. It really is very simple if you note down the correct sequence of events, without missing any out.
Le Repteux Posted September 17, 2014 Posted September 17, 2014 Le Repteux, Atomic or other clocks are irrelevent. Time measurement is not needed in Einstein's train experiment. If you do a real experiment, how can you be sure that the two flashes of light are simultaneous if you do not have a precise clock at each end of the train? This mind experiment needs clocks, exactly like GPS does. With pre-synchronized clocks, you know the emitted frequency, and you can calculate the distance at each second, so you have the speed. No need to ask ourselves if the signal is simultaneous for all observers, we know it is. Nope. You keep repeating the same mistake over and over. I will not explain why, I already did, i will just point out that you keep repeating the same mistake. Also nope. Very good arguments! I will try them next time you say something else than "nope".
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