madmac Posted January 27, 2017 Posted January 27, 2017 I had a look at the video, & am not impressed. If the observer on the platform was Einstein, & if he had all of the simple info & simple measurements & simple theory needed, then he would see or deduce every detail of what happed as the train passed, & he would deduce that the passenger (she) saw simultaneous flashes (as did he). Thusly, the train (thought) experiment (& thusly Einstein's SR) relies on having an observer that is ignorant of the critical measurements, or is too stupid. This probably makes this thought experiment & the resulting SR theory unique. I am ok with mathematical tricks, & weird models, if they give good answers, but i daresay that skoolkids are not warned of the difference tween models & reality. Here is how i try to make sense of SR. SR is a model not reality (that's ok). Time dilation & length dilation are not reality in SR, just a math trick (that's ok). There is no such thing as absolute time in SR, all time is relative (that's ok). What u see depends on your velocity (ok), & perhaps position (needs more thinking). Re simultaneity, i reckon that this is sometimes (bad choice of word) possible for observers in relative motion, albeit for only an instant, if the event has a centerline (an axis of symmetry), & if both observers are on that line (or plane). For example this-here train experiment (for one instant). Time will tell (pun intended). If Mrs Einstein were the passenger then she could make similar deductions re what her hubby saw, after all, she was the brain in the family. -5
pzkpfw Posted January 27, 2017 Posted January 27, 2017 I had a look at the video, & am not impressed. If the observer on the platform was Einstein, & if he had all of the simple info & simple measurements & simple theory needed, then he would see or deduce every detail of what happed as the train passed, & he would deduce that the passenger (she) saw simultaneous flashes (as did he). How? From the platform observers point of view, the train observer is moving towards one flash and away from the other. The train observer is next to the platform observer at the time the platform observer considers the flashes to have occurred. Since light travel isn't instant, the train observer (according to the platform observer) will have moved when the flashes reach them. The train observer can't see both of these two particular flashes at the same time. (Two different flashes might have occurred at the same time, according to the train observer - but then the platform observer couldn't consider them to be simultaneous.) Thusly, the train (thought) experiment (& thusly Einstein's SR) relies on having an observer that is ignorant of the critical measurements, or is too stupid. This probably makes this thought experiment & the resulting SR theory unique. No, you have this backwards; the "train (thought) experiment" relies on the postulates of SR. Your "ignorant of the critical measurements" comment (and your next bit) seems to imply that you think there's one absolute reality - relativity tells us this isn't true. For example, whether two events are simultaneous or not is not necessarily "true" or "false" for all observers. I am ok with mathematical tricks, & weird models, if they give good answers, but i daresay that skoolkids are not warned of the difference tween models & reality. Here is how i try to make sense of SR. SR is a model not reality (that's ok). Time dilation & length dilation are not reality in SR, just a math trick (that's ok). There is no such thing as absolute time in SR, all time is relative (that's ok). What u see depends on your velocity (ok), & perhaps position (needs more thinking). If you are so fine with "There is no such thing as absolute time in SR, all time is relative (that's ok)" - why do you you need to argue against relativity of simultaneity? Re simultaneity, i reckon that this is sometimes (bad choice of word) possible for observers in relative motion, albeit for only an instant, if the event has a centerline (an axis of symmetry), & if both observers are on that line (or plane). For example this-here train experiment (for one instant). Time will tell (pun intended). You start out correct here. e.g. If observer M is between events A and B and sees A and B at the same time, they will consider A and B to be simultaneous. Observer N could be moving relative to M, but also see the flashes at the same time (and consider them too be simultaneous) if their path keeps them at all times exactly between A and B. (In the usual thought experiment, this would be an observer away from the tracks, who travels towards or away from the platform observer, on a path perpendicular to the track). But this is a very special case in the relative motion of M and N; and does not contradict the thought experiment. If Mrs Einstein were the passenger then she could make similar deductions re what her hubby saw, after all, she was the brain in the family. No, she wouldn't, as shown by the thought experiment. She might be able to deduce that the platform observer did see these particular flashes at the same time, and thus that the events were simultaneous for the platform observer; but she'd see the flashes at different times herself, and knowing she was in the middle of the two events, and knowing her inertial frame is as valid as the platform observers', she'd know that meant they were not simultaneous (for her).
Janus Posted January 27, 2017 Posted January 27, 2017 I had a look at the video, & am not impressed. If the observer on the platform was Einstein, & if he had all of the simple info & simple measurements & simple theory needed, then he would see or deduce every detail of what happed as the train passed, & he would deduce that the passenger (she) saw simultaneous flashes (as did he). Thusly, the train (thought) experiment (& thusly Einstein's SR) relies on having an observer that is ignorant of the critical measurements, or is too stupid. This probably makes this thought experiment & the resulting SR theory unique. This argument holds no water. Below are a series of "snapshots" of events according to the platform observer. At the top we have the moment at which the platform obsever (Red dot) and the Train observer (Yellow dot), are adjacent to each other, and the flashes are initiated(white dots). Next we have some time later. The light flashes are shown by the white curved lines which represent the wave fronts of the light. Both are an equal distance from the Platform observer. And the right flash has reached point A on the tracks. The train observer has moved to the right of the Platform is is also at point A of the tracks. In other words, this is where the train observer and the right flash meet up and at this moment both the train observer and point A will be lit by only the flash from the right. Next we have a bit later when the flashes reach the platform observer and he sees both flashes simultaneously. The train observer has now moved on past point A. Finally we have both the left flash and the train observer arriving at point B. Now it is obvious that Point A and Point B are at different points of the tracks, and that the train observer had to take some non-zero time to travel between these two points. Thus time must have passed for the train observer between his( or her) seeing the flashes, and they could not have seen the flashes simultaneously. If you try to claim the the train observer sees the flashes simultaneously in their frame even though the platform frame says differently, you are setting a physical contradiction. If the train observer see the flashes simultaneously, they could only have seen them when they were next to a single point of the tracks upon seeing them. We can actually put measuring devices at points A and B that record when the flashes and train observer reaches them. We can also give the train observer a means of recording where they are relative to the tracks when they see the flashes. Afterwards we can bring these records together and compare them. If they disagree as to what events actually happened we have a physical contradiction. Worse yet, we even set up a situation where an event such as an explosion on the train occurs in one frame but not the other. How do you explain at the end of the experiment that you have both a destroyed and an not destroyed train. I am ok with mathematical tricks, & weird models, if they give good answers, but i daresay that skoolkids are not warned of the difference tween models & reality. Here is how i try to make sense of SR. SR is a model not reality (that's ok). Time dilation & length dilation are not reality in SR, just a math trick (that's ok). There is no such thing as absolute time in SR, all time is relative (that's ok). What u see depends on your velocity (ok), & perhaps position (needs more thinking). Except SR is a model of reality. It is a description of how "reality" really does behave. Actual physical experiment and observation has verified this again and again. If Mrs Einstein were the passenger then she could make similar deductions re what her hubby saw, after all, she was the brain in the family. If she was in the train with the experiment set up as it is, she would see the flashes at different times, and from this determine that her Hubby sees them simultaneously. The only way shes sees the flashes simultaneously is if you have changed the initial parameters of the experiment so that this is the case. You could set up a different pair of flashes that she sees simultaneously and Her Hubby doesn't, but this would be a completely different set of flashes than the one he sees as simultaneous. You could add these to the experiment, but then you would have 4 flashes of light, one pair that Einstein sees simultaneously and she doesn't, and another pair that she sees simultaneously and He doesn't. There is no way that both can claim that the same flashes were simultaneous for them but not for the other. 1
Strange Posted January 27, 2017 Posted January 27, 2017 If the observer on the platform was Einstein, & if he had all of the simple info & simple measurements & simple theory needed, then he would see or deduce every detail of what happed as the train passed, & he would deduce that the passenger (she) saw simultaneous flashes (as did he). Thusly, the train (thought) experiment (& thusly Einstein's SR) relies on having an observer that is ignorant of the critical measurements, or is too stupid. That conjecture seems highly unlikely as this thought experiment was created by Einstein in order to explain the relativity of simultaneity. 1
Mordred Posted January 27, 2017 Posted January 27, 2017 Also considering relativity is increbibly well tested. Which includes relativity of simultaneity
madmac Posted January 27, 2017 Author Posted January 27, 2017 Thanks guys (or should i say fellows so as not to be sexist), i appreciate the replies, & am working on my reply (that might surprise). Back soon.
Endy0816 Posted January 27, 2017 Posted January 27, 2017 Easier if you picture the flashes as expanding circles. One can see them as simultaneous(Point A) but the other based on their motion(or lack thereof) doesn't see the other flash reach them(occur) until Point B.
VandD Posted January 31, 2017 Posted January 31, 2017 No, she wouldn't, as shown by the thought experiment. She might be able to deduce that the platform observer did see these particular flashes at the same time, and thus that the events were simultaneous for the platform observer; but she'd see the flashes at different times herself, and knowing she was in the middle of the two events, and knowing her inertial frame is as valid as the platform observers', she'd know that meant they were not simultaneous (for her). Be carefull here. When the train passenger passes the platform passenger NONE of the two events occur for the train passenger! Hence stating the train passeger was in the middel of the two events sounds a bit awkward. For the train passenger first the front flash occurs when the train passenger is NOT YET at the platform observer. And the second flash occurs when the train passenger has already passed the platform observer. But the platform observer doesn't know this at the start of the experiment. The train observer can only reason as follows: << If both flashes also occur simultaneously for me when I meet embankment observer, then I am in the middle of the flashes and they happen at same distance from me, hence both lights from bolts HAVE TO reach me simultaneously. But.... the lights from the bolts do NOT reach me simultanously. It can only be because for me (in my frame), It can not be correct that lighting bolts occurred simultaneously when I and platform observer>> Actually the platform observer doesn't know when exactly the flashes occur. But that's not important. What is important for the experiment was to find out whether for the train observer the flashes happened simultanously or not. And the experiment gives the answer: they don't happen simultaneously for the train observer.
Phi for All Posted February 1, 2017 Posted February 1, 2017 ! Moderator Note These posts have been split off from the topic they were hijacked from, and moved to this section due to the speculative nature. Please take the time to review the special rules for the Speculations section.
swansont Posted February 1, 2017 Posted February 1, 2017 Time dilation & length dilation are not reality in SR, just a math trick (that's ok). No. Clocks actually do run at different rates when they move, and when they are in different gravitational potentials, and we have experimental confirmation of this fact.
VandD Posted February 2, 2017 Posted February 2, 2017 (edited) Be carefull here. When the train passenger passes the platform passenger NONE of the two events occur for the train passenger! Hence stating the train passeger was in the middel of the two events sounds a bit awkward. For the train passenger first the front flash occurs when the train passenger is NOT YET at the platform observer. And the second flash occurs when the train passenger has already passed the platform observer. But the platform observer doesn't know this at the start of the experiment. The train observer can only reason as follows: << If both flashes also occur simultaneously for me when I meet embankment observer, then I am in the middle of the flashes and they happen at same distance from me, hence both lights from bolts HAVE TO reach me simultaneously. But.... the lights from the bolts do NOT reach me simultanously. It can only be because for me (in my frame), It can not be correct that lighting bolts occurred simultaneously when I and platform observer>> Actually the platform observer doesn't know when exactly the flashes occur. But that's not important. What is important for the experiment was to find out whether for the train observer the flashes happened simultanously or not. And the experiment gives the answer: they don't happen simultaneously for the train observer. Why has my post been moved to the 'speculation' section????? This is unacceptable! My post has NOTHING to do with speculation. It's the correct down down to earth analysis of Einstein's thought experiment. @Modarator: Please explain why my post falls under speculations. Edited February 2, 2017 by VandD
studiot Posted February 2, 2017 Posted February 2, 2017 V&D Perhaps a more measured response would be to PM the moderator concerned? I have found the mods quite open and sympathetic to private discussion and quite prepared to adjust moderator action if a good case is made. You have provided some excellent and readable responses in several threads, particularly relativity, so please don't fall out with the mods, they do a super job under the circumstances. I expect that a whole block of posts were moved and if any fine adjustments become appropriate that can take a few days of quite background discussion. I don't know why relativity is one of those subjects some become over emotional about.
VandD Posted February 2, 2017 Posted February 2, 2017 Hi Studiot I don't see why I should go private to discuss this. It's of everybody's interest to know why my post is considered 'speculations'. I deal with Eistein's thought experiment for over 30 years now. It's the first time in my life the analysis is considered 'speculations'. Of course I'm emotional about it.
studiot Posted February 2, 2017 Posted February 2, 2017 Hi Studiot I don't see why I should go private to discuss this. It's of everybody's interest to know why my post is considered 'speculations'. I deal with Eistein's thought experiment for over 30 years now. It's the first time in my life the analysis is considered 'speculations'. Of course I'm emotional about it. Like I said, I expect a block of posts was moved. I'm not even sure how far they can sort individual posts within a block. A separation line has to be drawn somewhere and sometimes things get tangled up in this. I have 'suffered' this myself so it is not personal, However I would like to say that I, and quite a few others I think, value you contributions here.
VandD Posted February 2, 2017 Posted February 2, 2017 (edited) Like I said, I expect a block of posts was moved. I'm not even sure how far they can sort individual posts within a block. A separation line has to be drawn somewhere and sometimes things get tangled up in this. You mean a lot of CORRECT posts suffer being moved to the WRONG thread because of moving a 'block of posts', collateral damage so to speak? Is that the correct way to manage a forum? This forum needs urgently some computer expert to sort out the "block of posts" problem. If my post suffered collateral damage I don't see why I should not copy paste my post back in the correct thread. I wait moderation motivation. Edited February 2, 2017 by VandD
Klaynos Posted February 2, 2017 Posted February 2, 2017 You mean a lot of CORRECT posts suffer being moved to the WRONG thread because of moving a 'block of posts', collateral damage so to speak? Is that the correct way to manage a forum? This forum needs urgently some computer expert to sort out the "block of posts" problem. If my post suffered collateral damage I don't see why I should not copy paste my post back in the correct thread. I wait moderation motivation. Your post was moved as it replied to a reply of speculation. Not because your post was speculations. Most opening posts in speculations are speculations but most posts replying in those threads are not. If only the speculation post had been removed from the original thread then the replies and flow of the thread would have been very very odd. We therefore tend to move the offending post and the follow ups to a new thread. It is often difficult to draw the line in what is a follow up to the op and what is a follow up to the speculation. It shouldn't be considered a bad thing to have one of your posts in reply to a speculations thread. Of course what you've done by asking this question in this thread rather then using the report post function or starting a new thread on the issue is to hijack this thread which is against the rules. Note this isn't an official sanction just an observation. And if you think your post is still relevant to the other thread then sure, go for copying and pasting it back in. It is in my view better to have multiples of good and interesting information.
madmac Posted February 2, 2017 Author Posted February 2, 2017 (edited) swansont. Yes ticking usually slows or fasts if u move a clock to a different position or if u change a clock's speed. But here u will need a bit of patience while i put on my aetherist hat. Aetherists believe in absolute time (universal time). The fastest a clock can tick is when it is stationary in the aether (zero aether-wind). Clocks tick slower if they feel an aether-wind. They feel the speed of the wind, the acceleration makes no difference. Gravity is due to acceleration of aether (not vel). Aether accelerates into Earth & Sun & all matter. The general background aether-wind in our part of the cosmos is about 475 km/sec passing south to north approx. 25dg off Earth's axis. Einstein's relativity & aether theory give similar answers most of the time, & identical answers some of the time. But relativity cannot explain the diurnal change in ticking, only aether-theory can explain it. Lorentz (& Fitzgerald) gave an electromagnetic reason for length dilation, based on the vel of aether-wind. This was criticised by some, even though it is not ad hoc. And Lorentz gave an electromagnetic reason for time dilation, based on the speed of aether-wind, but this was ad hoc (u could use the same reasoning to suggest that ticking got faster instead of the desired slower). But Einstein did not give any reason whatever for time dilation & length dilation in relativity, certainly not any electro-dynamic reason (despite the title of his paper), he merely provided some math trickery that gave the supposed "correct" answers, based on nothing more than it explains the difference in what a moving observer supposedly sees & what a fixed observer supposedly sees, none of which is based on any reality at all. Here by electro-dynamic i mean re the shape of atoms contracting in a certain direction. The passage of light itself (photons) is not electro-dynamic, there isn't any electron involved (nor any charge)(but this is the first time i have given this any thought). Edited February 2, 2017 by madmac -1
swansont Posted February 2, 2017 Posted February 2, 2017 Hi Studiot I don't see why I should go private to discuss this. It's off-topic to discuss it here. That's why. swansont. Yes ticking usually slows or fasts if u move a clock to a different position or if u change a clock's speed. But here u will need a bit of patience while i put on my aetherist hat. Aetherists believe in absolute time (universal time). The fastest a clock can tick is when it is stationary in the aether (zero aether-wind). Clocks tick slower if they feel an aether-wind. They feel the speed of the wind, the acceleration makes no difference. Gravity is due to acceleration of aether (not vel). Aether accelerates into Earth & Sun & all matter. The general background aether-wind in our part of the cosmos is about 475 km/sec passing south to north approx. 25dg off Earth's axis. Great! Go out and definitively measure this aether-wind, and succeed where all others have failed. Until you do, though, you have no evidence of it. Einstein's relativity & aether theory give similar answers most of the time, & identical answers some of the time. But relativity cannot explain the diurnal change in ticking, only aether-theory can explain it. What diurnal change in ticking? (You need to get used to providing references/citations for your claims. Sooner rather than later) But Einstein did not give any reason whatever for time dilation & length dilation in relativity, certainly not any electro-dynamic reason (despite the title of his paper), he merely provided some math trickery that gave the supposed "correct" answers, based on nothing more than it explains the difference in what a moving observer supposedly sees & what a fixed observer supposedly sees, none of which is based on any reality at all. Math is not trickery (especially the basic algebra in that paper). Einstein assumed c is invariant because it is in electrodynamics, and derived the implications for kinematics. 2
madmac Posted February 3, 2017 Author Posted February 3, 2017 (edited) swansont. Re diurnal change in ticking. This is mentioned on -- page 34 & 35 -- Section 3.6, Clock Bias on and Near Earth -- of -- Report on the ["Clocks and the Equivalence Principle" by Ronald R Hatch] -- by Jonathan Alzetta (April 1, 2011). Alzetta says that Hatch said that -- "Hill reported that millisecond pulsars external to the solar system reveal a difference in clock rate between clock located at noon and at midnight". The difference is about 300 ps/sec, & is due to Earth's orbit & daily spin. SR does not recognise any orbital contribution. GR suggests that the difference should be only 0.42 ps/sec, ie due to a greater gravitational potential due to the sun at noon. Re the reality of Einstein's Relativity. I like the following 4 articles that i had a look at this morning that happen to be at the top of my list on my computer for no good reason, some of the other 14 further down my list might be better. These 18 articles are filed under GPS. I have perhaps 1000 articles, mostly related to aether, & some will be better than these 4 (re Einstein's Relativity). What the Global Positioning System Tells Us about the Twins's Paradox -- Tom Van Flandern (this is much more interesting than it looks). The GPS and the Constant Velocity of Light -- Paul Marmet (love it). Light Transmission and the Sagnac Effect on the Rotating Earth -- Stephan J G Gift (nice). GPS and Relativity: An Engineering Overview -- Henry F Fliegel & Raymond S DiEsposti (old article, but interesting). Plus look at all of Ronald R Hatch's articles, eg -- In Search of an Ether Drift. He is praps the guru of GPS. Re Aether-Wind. I like the articles (about 40 of them) by Prof Reginald Cahill (Adelaide) & his students & fellow staff. Cahill never uses the word aether, nor aether-wind. He uses the term Dynamic Space. Cahill discovered/invented the proper calibration for M&M, which takes into account the refractive index of air (& helium in some tests). Vacuum givs a null result (ie most modern tests). Actually i recently discovered that Cahill wasn't the first to find the proper calibration, but he is my hero nonetheless. The sad saga of De Witte (who was the first to measure the one-way velocity of light) will bring a tear to every aetherist's eyes. Cahill's discovery of what he calls Gravitational Waves is fascinating. Edited February 3, 2017 by madmac
studiot Posted February 3, 2017 Posted February 3, 2017 The sad saga of De Witte (who was the first to measure the one-way velocity of light) will bring a tear to every aetherist's eyes. I had always understood that Roemer was the first to measure this. https://en.wikipedia.org/wiki/R%C3%B8mer's_determination_of_the_speed_of_light
madmac Posted February 3, 2017 Author Posted February 3, 2017 Studiot. Thanks for thems links. Isnt history marvellous. Today scientists measure stuff to better than 1 part in a billion (but rubbish nonetheless) --- whereas the pioneers worked in the dark with homemade gear with little funding. -1
swansont Posted February 3, 2017 Posted February 3, 2017 I was hoping for peer-reviewed experimental confirmation when I asked you to provide references/citations for your claims. I shouldn't really have to specify that. Also, links, when available.
StringJunky Posted February 3, 2017 Posted February 3, 2017 (edited) Studiot. Thanks for thems links. Isnt history marvellous. Today scientists measure stuff to better than 1 part in a billion (but rubbish nonetheless) --- whereas the pioneers worked in the dark with homemade gear with little funding. You aren't a closet fan of Galileo, are you, and going to pull him out of the hat in the near future? Edited February 3, 2017 by StringJunky
madmac Posted February 3, 2017 Author Posted February 3, 2017 (edited) swansont. Most of my favourite sources-articles do not come from top journals because they are sceptical of the mainstream (censorship). Some are a review of the mainstream theory, a real peer review, not a (mainstream) pal review. But sometimes they provide new experimental info. Either way, i would love to see mainstream reviews of these reviews (rarely happens). An article might be say anti relativity, & the usual put-down is that it is anti relativity, & that relativity has been accepted & proven for umpteen years. I am easily bamboozled by science, but i reckon that i can get a good feel for truth by the way that scientists move & duck & punch. And when a scientist is in the ring on his/her own its hard to tell if he/she is good or bad. Re links, i usually mention a name &-or title, & hope that anyone interested will only take seconds to google. Cut & paste doesn't work for me on this forum. Almost nothing works, i even hav trouble getting italics or bold or underline (seriously). And hitting quotes doesn't give me quotes. It might be my satellite link down here in the bush, or kangaroos have been chewing the cables again. Perhaps my satellite still thinks that messages go east-west at the same speed as west-east. StringJunky. I have a vague idea of Galileo, didn't Newton plagiarise a lot off him(?). Didn't Galileo initially think that a ship actually got smaller as it sailed away? If Einstein wrote a thesis that a ship actually did dilate with relative distance, & that it was valid for an observer on the ship to believe that the pier moved because the pier was not absolute, then he would have been locked away, but in the modern era this sort of theory rules. Edited February 3, 2017 by madmac
swansont Posted February 3, 2017 Posted February 3, 2017 Re links, i usually mention a name &-or title, & hope that anyone interested will only take seconds to google. That's not good enough. People have to be able to easily check the validity of your sources, especially if you are vague in how they purport to back your claims.
Recommended Posts