Simultaneity of Relativity
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From: Inertial on 10 Oct 2009 05:29 "Bruce Richmond" <bsr3997(a)my-deja.com> wrote in message news:66ad9c9b-dc37-446a-8620-14d96850a4a6(a)v25g2000yqk.googlegroups.com... > On Oct 9, 7:55 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "Bruce Richmond" <bsr3...(a)my-deja.com> wrote in message >> >> news:ed15034f-aa9e-482e-b657-c5733eb61e87(a)a21g2000yqc.googlegroups.com... >> >> > On Oct 9, 10:52 am, PD <thedraperfam...(a)gmail.com> wrote: >> > Why not use the LET interpertation for the same math. The aether/ >> > water is not at rest with either the train or the embankment. But >> > because of the method used to sync clocks in each frame they both >> > measure the wave speed to be the same. >> >> And don't forget that, according to LET, movement through the aether >> makes >> *all* processes run slower, and *all* objects and distances (material and >> non-material) compress. In LET this is a physical change to the object >> itself (it gets truly compressed when speed in the aether increases, or >> expanded when speed in aether decreases) and a physical slowing of the >> processes (they run slower when speed in the aether increases, and faster >> when speed in the aether decreases). > > But the observer never detects that change because the measuring rod > changes in the exact same way as the object being measured. And LET says that every measurement of every physical property of the object remains unchanged. Even though (for example) if the earth was travelling fast enough wrt the aether it would be squashed to something almost disc-shaped > The > method of clock sync hides the differences in light speed and length > contraction. Not really .. its the combination of the change in length and change in time and clock sync. Of course, the method of clock sync is the only sensible clock sync we have.
From: PD on 10 Oct 2009 09:48 On Oct 9, 10:23 pm, mpc755 <mpc...(a)gmail.com> wrote: > On Oct 9, 5:54 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Oct 9, 4:13 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > On Oct 9, 4:29 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Oct 9, 2:47 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > On Oct 9, 3:33 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > On Oct 9, 3:26 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > On Oct 9, 2:04 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > > > On Oct 9, 2:38 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > On Oct 9, 12:26 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > > > > > > > > That's just it. Whether they are simultaneous or not depends on the > > > > > > > > > > > > > signals they actually receive at their locations. That is, the > > > > > > > > > > > > > observers M and M' are not AT the locations A, A', B, B'. They are at > > > > > > > > > > > > > the places marked M and M'. What they know is what happens where they > > > > > > > > > > > > > are, and THAT tells them what happens at A, A', B, and B'. They have > > > > > > > > > > > > > no other way of knowing. > > > > > > > > > > > > > There are observers at A, A', B and B' and they all have clickers and > > > > > > > > > > > > they all click their clickers when the pebbles hit the water. It is > > > > > > > > > > > > determined all four observers hit their clickers at the same time. > > > > > > > > > > > > How is it determined that they hit their clickers at the same time? > > > > > > > > > > > What procedure would you need to ensure that? > > > > > > > > > > > I want you to think about this very carefully... > > > > > > > > > > > There are observer as close to each contact point between the pebble > > > > > > > > > > and the water as possible. The length of wire from the clicker to the > > > > > > > > > > clicker response unit is the same for all observers. > > > > > > > > > > And the speed of the signal is the same through the wire in both > > > > > > > > > cases. > > > > > > > > > > So if the speed in the wire is the same, and the length of the wire is > > > > > > > > > the same, then you know that the time propagation through the wires > > > > > > > > > would be the same, right? > > > > > > > > > > And if this is the case, then you know the following: > > > > > > > > > 1. If the clicker response unit records signals from the clickers at > > > > > > > > > the same time, THEN you know that the pebbles landed at the same time. > > > > > > > > > 2. If the clicker response unit records signals from the clickers at > > > > > > > > > different times, THEN you know that the pebbles landed at different > > > > > > > > > times. > > > > > > > > > > Right? This is how you determine from the clicker and clicker response > > > > > > > > > system whether the pebbles really landed at the same time or not. > > > > > > > > > > OK, so here's the situation with the lightning strikes: > > > > > > > > > You've got ONE lightning strike at one end of the train, and ONE > > > > > > > > > lightning strike at the other end of the train. > > > > > > > > > The path length (just like the wire length) from one lightning strike > > > > > > > > > to the observer M is the same as the path length from the other > > > > > > > > > lightning strike to the observer M. Equal path lengths, just like > > > > > > > > > equal wire lengths. > > > > > > > > > The path length (just like the wire length) from one lightning strike > > > > > > > > > to the observer M' is the same as the path length from the other > > > > > > > > > lightning strike to the observer M'. Equal path lengths, just like > > > > > > > > > equal wire lengths. > > > > > > > > > And you know the speed of the signal from one lightning strike to M is > > > > > > > > > the same as the speed of the signal from the other lightning strike to > > > > > > > > > M. > > > > > > > > > And you know the speed of the signal from one lightning strike to M' > > > > > > > > > is the same as the speed of the signal from the other lightning strike > > > > > > > > > to M'. > > > > > > > > > > The problem is, in experiment, M says he received the signals at the > > > > > > > > > same time (clicker case (1)), and M' says he received the signals at > > > > > > > > > different times (clicker case (2)). > > > > > > > > > Just like there are four observers at A, A', B, and B' > > > > > > > > There aren't four observers at A, A', B and B'. > > > > > > > Read it again! > > > > > > > You asked me how the pebbles dropped at A, A', B, and B' could be > > > > > > determined to be simultaneous and I explained how with four observers, > > > > > > one at each pebble drop. > > > > > > > > > the lightning > > > > > > > > strikes occur at 4 points. > > > > > > > > Wow! One lightning strike strikes in two places at once! > > > > > > > LOL!! > > > > > > > Yes. When it leaves a mark on the train and on the embankment. This is > > > > > > two different places. > > > > > > > > > When the light from the lightning strikes > > > > > > > > reach M and M' are dependent on the medium the light travels through. > > > > > > > > Especially when it's ONE medium! > > > > > > > > You're a hoot, you are! > > > > > > > Water is one medium, but if it is on the train and stationary relative > > > > > > to the train and water is on the embankment stationary relative to the > > > > > > embankment, pebbles dropped at A, A', B, and B' will have their > > > > > > associated waves from A and B reach M and from A' and B' reach M' > > > > > > simultaneously. > > > > > > Let's see if we can find any common ground. Forget Einstein's Train > > > > > Thought Experiment for a second. > > > > > Nah, that's was the whole point. You were trying to explain what > > > > relativity says would happen in the train gedanken and what you say > > > > would happen instead. > > > > > Now you don't want to talk about the train gedanken at all, not to > > > > mention what's measured in real experiments that are related to it, > > > > using real light. > > > > > > We have an embankment that is knee deep in water. The water on the > > > > > embankment is stationary relative to the embankment. We have an > > > > > enclosed train that is need deep in water. The water on the train is > > > > > stationary relative to the train. > > > > > > Four pebbles are dropped at A and B on the embankment and A' and B' on > > > > > the train. A and B are equi-distant from M and A' and B' are equi- > > > > > distant from M'. The distance from A and B to M is the same distance > > > > > as A' and B' are to M'. > > > > > > The pebbles are dropped simultaneously at A and A'. > > > > > > The pebbles are dropped simultaneously at B and B'. > > > > > > If the waves from A and B reach M simultaneously, then the waves from > > > > > A' and B' reach M' simultaneously. > > > > I'm just pointing out to you what happens if the medium the wave > > > travels through on the embankment is stationary relative to the > > > embankment and the medium the wave travels through on the train is > > > stationary relative to the train. It's an analogy. > > > > And if you then take the analogy of a pebble in water and you modify > > > the analogy to be light traveling through water you will come to the > > > same conclusion. > > > > If the light waves from A and B reach M simultaneously then the light > > > waves from A' and B' reach M' simultaneously. > > > > You then change the medium to be aether instead of water and the same > > > conclusion holds true. > > > > If the light waves from A and B reach M simultaneously then the light > > > waves from A' and B' reach M' simultaneously. > > > As I said in the beginning, the train gedanken was designed to explain > > relativity to people who have a hard time understanding it. It makes a > > certain class of predictions that can be tested in equivalent > > experiments. Those predictions match what is actually observed. > > > You have a scenario that has nothing to do with the train gedanken, > > involving two tanks of water slipping past each other with pebbles > > dropped in them in four different places. This doesn't make any > > predictions, as far as I can tell, about what would be measured with > > light. If you think it does, and it makes predictions other than what > > relativity says, then I'm afraid the experiments have already ruled > > your model out. > > > PD > > My scenario has everything to do with the Einstein's train thought > experiment. You say that, but then you say "Forget the Einstein gedanken" just as we were getting started explaining it to you.
From: PD on 10 Oct 2009 09:50 On Oct 9, 10:31 pm, mpc755 <mpc...(a)gmail.com> wrote: > On Oct 9, 7:50 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > > On Oct 9, 1:26 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > On Oct 9, 1:17 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Oct 9, 12:08 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > On Oct 9, 12:30 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Oct 9, 10:06 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > > On Oct 9, 10:52 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > On Oct 9, 8:53 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > > > > On Oct 9, 8:57 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > > On Oct 8, 8:34 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > > > > > > > > > > > > > > > Sorry, I've fouled this up. > > > > > > > > Yes, the light from A and B reaches M' at different times, but the > > > > > > > light from A' and B' reaches M' simultaneously. > > > > > > > A and A' are a single strike. B and B' are a single strike. > > > > > > Yes, A and A' are a single strike but A and A' are two different > > > > > locations in three dimensional space. A in on the embankment and A' is > > > > > on the train. > > > > > No, they are not. You have not read the gedanken carefully. A lighting > > > > strike hits in ONE place, not two. A and A' are two labels for the > > > > same point. In the original gedanken, A and A' label the point where > > > > the train meets the track at one end of the train. That is ONE POINT. > > > > > Please reread it and pay more attention than what you have been doing > > > > so far. > > > > The lightning strike leaves marks at A, A', B, and B'. This is four > > > different locations in three dimensional space. A and A' and B and B' > > > were co-located at the time of the strikes, but they are four > > > different locations. > > > > If A and A' are two labels for the same point, why does the Observer > > > at M measure to A and B and the Observer at M' measure to A' and B'? > > > The measure to the appropriate marks because there are four marks. > > > > Please try and understand if you have four marks at four locations > > > that is four points. > > > The mark at A on the tracks and the mark at A' on the train were made > > when the two points were together. > > > M considers the strike to have happen at A. There are scorch marks on > > the tracks marking the spot. There are also scorch marks on the > > train, but the train is moving relative to the tracks, so the marks on > > the train are not where the strike took place in the track frame. > > > M' considers the strike to have happen at A'. There are scorch marks > > on the train marking the spot. There are also scorch marks on the > > tracks, but the tracks are moving relative to the train, so the marks > > on the tracks are not where the strike took place in the train frame. > > > > > > > The light from A/A' travels through the *same medium* that the > > > > > > embankment and the open flatbed train cars are immersed in. The light > > > > > > from B/B' does the same thing. > > > > > > So how does the light, coming from a single lightning strike (A/A'), > > > > > > traveling through a common medium, arrive at the same observer M' both > > > > > > simultaneously and not simultaneously as the light from B/B'? > > > > > > It doesn't. If the train contains open flatbed cars, then you are > > > > > implying the medium is stationary relative to the embankment. > > > > > No, I'm not. There's no such implication at all. What you know is true > > > > is that there is ONE medium, not two. > > > > If there is one medium that is stationary relative to one of the > > > frames of reference in Einstein's train thought experiment then that > > > means it is moving relative to the other frame of reference which > > > means there is a preferred frame of reference. > > > There is only one medium and it is not stationary relative to either > > frame, so neither one is preferred. > > What if there is water that is stationary on the train and water that > is stationary on the embankment and a lightning strike occur > simultaneously at A' on the train and A on the embankment and another > lightning strike occurs simultaneously at B' on the train and B on the > embankment. If the light from the lightning strikes at A and B travels > through the stationary water on the embankment and reaches M > simultaneously, does the light from the lightning strikes at A' and B' > travel through the stationary water in the train and reach M' > simultaneously? If there were two bodies of water moving past each other, then there would be a transition layer between them. There would HAVE to be if the train observer was out in the open. This would mean that if the train observer moved to one side of the car, into the transition layer, then he'd be able to see the effect of the incompletely dragged medium. This has never been observed.
From: PD on 10 Oct 2009 09:50 On Oct 9, 10:27 pm, mpc755 <mpc...(a)gmail.com> wrote: > On Oct 9, 7:04 pm, Bruce Richmond <bsr3...(a)my-deja.com> wrote: > > > > > On Oct 9, 11:06 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > On Oct 9, 10:52 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Oct 9, 8:53 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > On Oct 9, 8:57 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > On Oct 8, 8:34 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > > > > > > > > > > > Sorry, I've fouled this up. > > > > > > > > > > > > > > > > > What Einstein's gedanken says is that the light from A/A' and the > > > > > > > > > > > > > > > > light from B/B' arrive simultaneously at M and NOT simultaneously at > > > > > > > > > > > > > > > > M'. > > > > > > > > > > > > > > > > > And if this were viewed from M', because the propagation toward M' is > > > > > > > > > > > > > > > > c from either A/A' or B/B', then it would be clear that events at A > > > > > > > > > > > > > > > > and B were not simultaneous. > > > > > > > > > > > > > > > > > PD > > > > > > > > > > > > > > > > OK, at least you now understand Relativity of Simultaneity. > > > > > > > > > > > > > > > > In Simultaneity of Relativity, both frames are equal. > > > > > > > > > > > > > > > That's all well and good, but experiment agrees with Einstein, not > > > > > > > > > > > > > > with your picture. > > > > > > > > > > > > > > How would you know? You just figured out what Relativity of > > > > > > > > > > > > > Simultaneity is two minutes ago. > > > > > > > > > > > > > :>) > > > > > > > > > > > > Well, I certainly did have difficulty explaining it right at first. > > > > > > > > > > > > > But the experimental stuff has been figured out a long time ago. > > > > > > > > > > > > > > > > Consider the > > > > > > > > > > > > > > > aether to be 'entrained' by the embankment in the embankment frame of > > > > > > > > > > > > > > > reference and for the aether to be 'entrained' by the train in the > > > > > > > > > > > > > > > train frame of reference. > > > > > > > > > > > > > > > OK, but the train observer could well be sitting on top of the train > > > > > > > > > > > > > > out in the open air, right along with the air that is surrounding the > > > > > > > > > > > > > > embankment. > > > > > > > > > > > > > > So unless you've got overlapping aethers, one passing through the > > > > > > > > > > > > > > other, then there would have to be a boundary between the two moving > > > > > > > > > > > > > > masses of aether, where they are rubbing up against each other. And in > > > > > > > > > > > > > > that case, there would be a region of aether in between where it is > > > > > > > > > > > > > > moving somewhat in between what the two entrained aethers are moving. > > > > > > > > > > > > > > And then just by moving, say, the embankment observer a little closer > > > > > > > > > > > > > > to the train, or the train observer a little to one side, then you'd > > > > > > > > > > > > > > start seeing the effect of the aether moving at a speed somewhat in > > > > > > > > > > > > > > between. However, this is not observed in equivalent experiments. > > > > > > > > > > > > > > Post a link to the experiments you are referring to. > > > > > > > > > > > > > Google "experimental basis for relativity" > > > > > > > > > > > > If you say this is not observed in equivalent experiments, you should > > > > > > > > > > > be willing and able to backup up such a statement with specifics. > > > > > > > > > > > > But, since you just figured out what Relativity of Simultaneity is > > > > > > > > > > > five minutes ago, its understandable you can't backup the claims you > > > > > > > > > > > make. > > > > > > > > > > > Such cheesy baiting. > > > > > > > > > > If you actually do the search I recommended, and you click on the > > > > > > > > > > FIRST link it returns, you'll have a lovely list of experiments. > > > > > > > > > > If you cannot do even this without whining, is it an indicator that > > > > > > > > > > you are hopelessly lazy or hopelessly incompetent? > > > > > > > > > > > > > > > This is what I mean by following the implications of an idea all the > > > > > > > > > > > > > > way through to look for *uniquely distinguishing* predictions. I've > > > > > > > > > > > > > > just given an example of a clear implication of AD, one that would be > > > > > > > > > > > > > > testable. And unfortunately, it doesn't match experiment. So it's > > > > > > > > > > > > > > gotta be wrong. > > > > > > > > > > > > > > Experiments like de Sitter and the double star? > > > > > > > > > > > > > No. That has to do with something else entirely. > > > > > > > > > > > > That has to do with a test that distinguishes ballistic emission > > > > > > > > > > > > theory and relativity. > > > > > > > > > > > > Nothing to do with simultaneity. > > > > > > > > > > > > Simultaneity of Relativity is emission theory in an entrained aether. > > > > > > > > > > > No, it's not. In your theory the speed of light is relative to the > > > > > > > > > > aether. In ballistic theory it is relative to the source. > > > > > > > > > > If the train is half full of water and the water is stationary in the > > > > > > > > > train and you drop pebbles at A' and B', the waves from A' and B' will > > > > > > > > > reach M' simultaneously. > > > > > > > > > > If the embankment is half full of water and the water is stationary > > > > > > > > > relative to the embankment and you drop pebbles into the water at A > > > > > > > > > and B, the waves from A and B will reach M simultaneously.. > > > > > > > > > > If you drop pebbles into the water at A and A' simultaneously and drop > > > > > > > > > pebbles into B and B' simultaneously, if the waves from A and B reach > > > > > > > > > M simultaneously, the waves from A' and B' will reach M' > > > > > > > > > simultaneously. > > > > > > > > > If it helps, MPC, Einstein's train gedanken can just as well take > > > > > > > > place on open, flat-bed cars. > > > > > > > > The water is stationary relative to the embankment and the train is > > > > > > > moving along under the water and not affecting the water. Pebbles are > > > > > > > dropped at A/A' and B/B'. The wave from B/B' travels from B to M'. The > > > > > > > waves from A and B and reach M simultaneously. The wave from A reaches > > > > > > > M'. > > > > > > > And notice that the waves from A and B do not arrive at M' at the same > > > > > > time. > > > > > > Yes, because the water is stationary relative to the embankment. In > > > > > this scenario, the embankment is the preferred frame. > > > > > > For Einstein's train thought experiment to be truly relative, there > > > > > can be no preferred frame. > > > > > > Therefore, the water must be stationary relative to the embankment in > > > > > the embankment frame of reference and stationary relative to the train > > > > > in the train reference frame. > > > > > Yes! And notice that, because the train cars are open, flatbed cars, > > > > you have to satisfy both criteria at the same time! > > > > > Here's where the fun starts. So if there is an aether (or water as you > > > > want to analogize), it has to be stationary with respect to the > > > > embankment AND to the train, at the same time. Not different > > > > scenarios. At the same time. > > > > > > In this scenario, my animation holds in the light from A and B reaches > > > > > M and the light from A' and B' reaches M' simultaneously. > > > > > No, certainly not. Because it's the same medium. > > > > The embankment observer notes that the light from A and B reaches M' > > > > at different times. > > > > Yes, the light from A and B reaches M' at different times, but the > > > light from A' and B' reaches M' simultaneously. > > > There is only one wave front emitted at A/A' and one at B/B'. Your > > inimation is wrong.> > The train observer has to agree with that. > > Why is everyone afraid to answer my thought experiment with pebbles > and the waves they create and stationary water on the train and > stationary water on the embankment? > > If pebbles are dropped simultaneously at A and A' and pebbles are > dropped simultaneously at B and B', if the waves from A and B reach M > simultaneously do the waves from A' and B' reach M' simultaneously? Answer in what way? It doesn't pertain to the Einstein gedanken, which is done out in the open so that at best there is ONE medium.
From: PD on 10 Oct 2009 09:52
On Oct 9, 10:25 pm, mpc755 <mpc...(a)gmail.com> wrote: > On Oct 9, 6:14 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Oct 8, 11:49 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > If the aether is stationary relative to the embankment and stationary > > > relative to the train, this is what will occur in Einstein's train > > > thought experiment: > > > >http://www.youtube.com/watch?v=jyWTaXMElUk > > > I think the end result of this discussion, MPC, is that you've never > > understood what's being said in the Einstein train gedanken. > > > At this point, it might have been effective for you to say, "I guess I > > don't understand what Einstein was trying to say. Is there anyone that > > is willing to walk through it with me to explain to me what it's > > saying?" > > > For some people this is emotionally difficult to do. One recourse for > > such people is to pretend that they understand what they do not, and > > to try to invent something they can at least call their own, because > > they do understand what they invent for themselves. The problem is, > > this has nothing to do with science, where the value of an idea is > > determined by how nature really acts, not how intuitive it is in our > > heads. > > > The right steps are to ask the following: > > 1. "What is this relativity theory, exactly, and what does it say?" > > 2. "OK, now that I understand what it claims, what makes you think > > it's right?" > > 3. "If there are other claims that have been put forward that are > > different, how do you know that any of those are not right?" > > > PD > > I understand exactly what is occurring in Einstein's Train Thought > experiment. Not as Einstein explained it, no you don't. You understand the MPC Train Thought Experiment, which is something completely different than the Einstein Train Thought Experiment. > > Lightning strikes at A/A' and B/B' behave exactly like the waves of > pebbles dropped into stationary pools of water on the train and > stationary pools of water on the embankment. > > If there are stationary pools on the train and on the embankment, the > waves the pebbles create from A and B reaches M and the light from A' > and B' reaches M' simultaneously. > > If there are stationary pools on the train and on the embankment, the > light waves from A and B reach M and the light wave from A' and B' > reach M' simultaneously. See? That's the MPC Train Thought Experiment, not the Einstein one. |