FC, you know that there are an infinite number of reference frames that could be chosen. In all but one of those both the station and the train are moving and thus the light could not get to either of them such as to stop either clock. In only one of those infinite frames, the station isn’t moving but the train is. And in only one of those the train isn’t moving and the station is.
Just from the probability stand point, when you have only one chance out of an infinite number of possibilities, the probability is 0%. On the other hand when you have an infinite number minus two chances out of an infinite number, the probability is 100%.
If there were 98 other observers passing the station each going at a different speed, they all would predict that neither clock would stop. That is 98 out of 100 observers, each using SR for their prediction.
Good for James for presenting his lie about people twice. It’s a good sophist technique.
So let me repeat what I did before:
In the reference frame in which the trains are not moving, the leading train is at 0.7089, the middle train is at -70.18 and the trailing train is at -141.1. The station is moving towards them at 0.99. The trailing edge of the station passes the leading train at 0.7089. The leading edge of the station passes the trailing train at 141.1.
How long does it take for the light from the leading train to get to the middle train? About 70.89, the same time from the trailing train to the middle train. So we know that the light from the leading train gets to the middle train at 71.6 and that the light from the trailing train reaches the middle train at 212. These are not the same time, so if that clock is waiting for the flashes at the same time to stop, it will not stop.
I suspect that what James is really asking for is for the SR person to set up a different scenario in the train frame than it is in the station frame. I know, I know, it would be really stupid to set up two different scenarios and then be surprised when they turn out differently. That’s what James wants, however.
Again we find something that indicates that James is either lying about SR or really, really doesn’t understand it. For one thing, there are an infinite number of frames in which the trains are not moving. We can assign whatever static coordinates to a train that we want, as long as we keep the relationships between the trains and the station fixed properly. More importantly, in every frame in SR, the same events always happen because that is what SR is made to do.
James wants us to use SR incorrectly. And he wants you to ignore actually working through the problem but instead look at his pictures.
In the train’s frame the distance between the train clock and LT and also TT is 10.
In your example, the station calculates the figures -141.1, -70.18, and 0.7089 (presuming length contraction).
And you might also want to look into how you got;
“How long does it take for the light from the leading train to get to the middle train? About 70.89, the same time from the trailing train to the middle train. So we know that the light from the leading train gets to the middle train at 71.6 and that the light from the trailing train reaches the middle train at 212.”
OK, so you openly admit that you want someone to use SR incorrectly.
I might be charitable and believe that you are simply too stupid to understand the physics, but you have a history of lying.
Were you looking in the mirror when you thought those words?
I suspect so.
In SR, the train observer does not see his train expanding to match the passing station clocks perspective. What if there was also a car passing? Would the train observer see two sizes of his train?
PB, if you are going to try to defend SR, it might help if you learn it first.
You have been lying about it and me since you first got on this thread in your misguided loyalist endeavor to defend it.
Trains observe nothing.
The question is what is the location assigned to various points in a given system of measurement.
If you assign coordinates in one reference frame, under SR that fixes the coordinates in all other reference frames.
So in this case, the distance between the trains according to O’ is always the same. We happen to know what the distance is because it was given to us in another reference frame.
So far, the only thing you have claimed that I got wrong is that I applied length contraction and you don’t like it. Since every textbook and source on the internet says that SR introduces length contraction, I’ll stick with that.
Other people who read this thread can also compare those sources with your ramblings. The only person who cannot is you.
The only person demonstrated to be lying on this board is you. You were the one who claimed that Feynman said something he didn’t. It was a stupid, foolish lie that anyone could easily check, but you did it anyway.
Neither do stations.
From a given frame of reference (which happens to be what SR is entirely about).
IF you the observer in that one.
BUT if you are the observer in another frame, in this case, you get contradictory predictions.
Trying to use merely one frame, presuming, and declaring truth is what blinds the mind and leads to all errors throughout the history of mankind. Verification is what Science is about, not presuming from a single prophetic authority.
Frames can’t “give” each other their measurements any more than the local priest can give you your values.
Learn what SR is about.
No. Any observer can use any reference frame. SR is about systems of coordinates that anyone is free to use. The results are invariant for every observer. Unless one uses the special use of the word “observer” that means reference frame, not a person who observes.
You have been told this before, but you prefer not to listen or read anything on this subject or to simply lie about the contents of SR.
The nature of “observer” talk in SR even has its own wikipedia page. en.wikipedia.org/wiki/Observer_% … ativity%29
Yes, and so far, scientific results support special relativity, not your fantasy physics.
All measurements are given in terms of some frame of reference. Once they are given in one frame, SR says that they are fixed for any well-formed frame of reference. That’s the science.
If you think that you can do better, then let’s see you actually set up the scenario as it should be done. So far, you have taken the illiterate route of drawing pictures and the poor character route of lying.
Then prove it by doing it.
Be the observer that was always on the train and was never given any measurements from some guy on the station. That observer doesn’t see his train becoming longer as he accelerates up to speed. He sees/measures his train to be just what it was before. He sees a station passing by at 0.99c. He knows that his flashers can only go off by being aligned with the triggers which he also knows are preset to ensure that they will both go off together.
Calculate using another frame, not the frame that you first favored.
SR forbids favoritism in reference frames, “privileged reference frame”.
You are saying nothing (as usual).
There is only one physical reality where the flashers can be triggered simultaneously. The clock which is moving at the same speed as the flashers will stop. Any clock which is moving relative to the flashers will not stop because the flashes will not be simultaneous.
Physical configuration trumps reference frames and observers. Observers don’t make anything happen. Reference frames are a mathematical abstraction.
If we say that, in the frame where the station is at rest, that the distance between each train at maximum speed is 10, then in the frame where the trains are at rest they must be much farther apart. If we say that the trains are 10 apart in the frame in which they are at rest, then they will be much closer together in the frame in which the station is at rest. These are just the facts of the Lorentz transformation. hyperphysics.phy-astr.gsu.edu/hb … trans.html
Exactly: much larger than it seems in the reference frame associated with the station.
You want to force the distance to be the same in all frames of reference through the force of your whining. This doesn’t work.
I have gone to a lot of trouble to give proofs of how that statement is NOT true.
How about you give something other than a quote from your Holy Book of Babel as a proof of that assertion.
We have all agreed, including the Holy Book of Babel, that the speed of the flashers is irrelevant.
The speed of the light is independent of the speed of the flashers.
And furthermore, the position of the flashing is preset to ensure simultaneity before there is any motion or differing frames of reference. The train clock is automatically centered and then either by pre-adjusted timers or by preset triggers, the flashers flash together. There is no way to get out of the fact that they flash together, regardless of any reference frame involved.
And that is exactly how they all know that the flashes occur simultaneously even before they observe any light.
They begin in the same frame at a distance of Xs = 10. From the train’s perspective, that doesn’t change. You are allowed to proclaim that it changes from the station’s perspective if you want, although that will merely complicate your math. It will not change the result. So go ahead and assume that the station sees the train contract if you like. But since you are NOW to be the train observer, you cannot say that the train sees himself contracting and what the station sees is actually irrelevant. You are not the station any more. If you are going to use length contraction, it is now the station that contracts, but you don’t care because the station is nothing but a clock. The timers ensure that given whatever contraction you want to use, they still flash together because they are preset, pre-calculated, pre-adjusted to ensure that they do so.
If you want to use that, it’s fine with me. Just stop babbling about it and use it.
Although you gave one perspective, the station’s, now you need to give another, the train’s (or any of an infinite number of others). You’re back to being all mouth and no math.
The reason that you see a paradox is because you attempt to force a simultaneous flash for both the station and the train. If you developed the scenario consistently, then you would find that there is no paradox.
I have written about this before but here goes another attempt:
Train front and rear separated by distance 2Xs as seen by the station.
-
Trigger by feeler arms or optical sensors:
Physical devices places at a distance Xs from the station make contact with the front of the train and the rear of the train. Each trigger produces a flash in the rear and front flashers which act independently.
The triggering mechanism is not moving relative to the station. You have forced simultaneous flash for the station clock. Therefore, in this situation, the station clock will stop.
What happens in the train? The train measures the distance between front flasher and rear flasher to be greater-than-Xs. Therefore when the front flasher passes the front trigger point, the rear flasher will not be at the rear trigger point. The rear flasher will pass the rear trigger point AT A DIFFERENT TIME. Therefore, the flash is not simultaneous for the train.
This situation is simply Einsteins lightning flash example. -
Trigger at midpoint of train and midpoint of station:
Trigger device placed at the midpoint of station makes contact with midpoint of train.
Once the train detects the trigger, a mechanism causes a flash at front and rear of the train. The flash mechanism is not moving relative to the train. You have forced a simultaneous flash for the train clock. Therefore, in this situation, the train clock will stop.
What is the orientation of the train when this flash happens? The train measures as greater-than-Xs, so the front of the train has already passed the front trackside Xs marker and the rear of the train has not yet reached the rear trackside Xs. marker.
What happens at the station? The rear flash is seen before the rear marker position is reached. The front flash is seen after the front marker position is reached. No simultaneity. This is a direct consequence of the orientation when the flashes are produced by the train. -
Triggers trackside and timed flash inside the train
This is a violation of what happens in situation 1. Therefore, it can’t be physically made to work this way.
Before the light starts moving, the flash has to operate. If you have a metal rod synchronizing front and rear flasher, then that physical rod will force simultaneity . Or the electronic circuit will force simultaneity. The mechanism which makes the flash operate is not going to suddenly produce non-simultaneous action. It’s not going to go crazy for the person who is there moving with the mechanism.
So now you are going back to the first scenario I detailed, the one that you said used broken clocks. But even in that scenario, there was no simultaneity because simultaneity is not about what any particular clock says, but about what ideal clocks should do.
So again, your beef with SR is that it doesn’t do what you want it to do. No amount of whining will make SR do what you want it to do.
Already done. The sad thing is that you can’t see it.
I don’t “attempt to force it”. The scenario is such that all observers already know that the flashers go off together. There is no alternative.
You got that part right.
But that is the part where you fell.
Remember this pic?
The front and rear engines accelerate independently so as to ensure that they arrive at an Xs distance (in the station frame) from the station clock together while keeping the train clock centered. Thus the train observer already knows that they trigger together despite anything he might see. He knows that the light might take more or less time to get to the train clock from each flasher, so he can’t use Einstein’s lightening scenario and simply presume that what he sees defines reality.
So you really do have both observers fully knowing that the flashers are triggered together regardless of anything they might see (unlike Einstein’s lightening strikes where they do not know and thus just presume by what they see). If they ignore their knowledge of the situation merely to accept what they see (denying Logic, that “A is A”), they have “affirmed the consequent” and also one of them must always be wrong because a clock will either stop or not. The whole point is to test what they see versus reality. If you declare that whatever they see defines reality, then you have merely denied logic with a logic fallacy, made a circular argument, and made your test un-falsifiable and pointless.
You asked what happens to the clocks. I told you and gave reasons why it happens.
The clocks do not define reality… the clocks reflect reality. The clocks are oblivious to ‘your logic’.
That is simply crazy.
SR guarantees that the two flashers can’t go off together, so you are merely denying SR.
But you can’t say that you are using SR when you start with an assumption that is obviously contradictory with SR.
But this doesn’t guarantee that they are the same distance apart in all reference frames. Nor does it guarantee simultaneity in all reference frames.
It doesn’t matter what the observer sees. What matters is what an ideal system of coordinates with clocks would assign to the events. And under SR, this will always mean a different distance and a different time.
You never work through a problem because you know that’s what SR will say. Then when people show you this, you change goalposts or you claim that they are merely being sheep by following what other people say.
It is not being a sheep to actually know something. I know lots about scientific theories that were false; I know that they are wrong because I compare what they say with what evidence there is. One cannot use evidence without knowing the thing that one is applying evidence to.
The lightning scenario is merely a pop science example of one case. You need to actually read what Einstein wrote in legitimate scientific papers. Even here, however, you are wrong. Any person on the train can make a judgment about simultaneity based on light times, because we always know that light moves at the same speed relative to a given system of measuring length. It is always a perfect standard, unless one wants to abandon SR entirely and start from some other assumption. But then this scenario doesn’t test SR, it tests something else.
There are two big differences here.
The first is that it is not perceptions that define reality, but an ontological commitment to the speed of light. If the speed of light is always the same relative to an ideal standard of measurement, then it is something that we can always use to rely upon to judge our perceptions. Thus it is a correcting agent to how we might other wise assume things (like that we can be careful enough to move trains without their distance changing).
The second is that SR makes real-world predictions that make real-world tests. Nothing in this foolish and self-contradictory scenario stops SR from passing those myriad tests.
Here is another way to look at this:
The train is stationary at the station. The stationmaster and train driver have identical tape measures and they mark out a distance of 100 meters between two markers along the tracks.
The train driver agrees to accelerate the train so that the contracted length as seen by the stationmaster will be 100 meters.
The train accelerates to the agreed speed and maintains that constant speed. The train driver uses his measuring tape and notes that the separation between the front and rear of the train is greater than 100 meters. The train driver takes a measurement of the separation between markers as he passes the station. He measures a distance which is less than 100 meters. The station and marker separation is contracted.
Do you now see why the front and rear of the train will not line up with the markers?
What I see is that you are not reading what I wrote and seem to totally misunderstand the scenario.
It seems that both you and PB, despite your serious differences, have each reached your limits.