Truden

Based on LOGIC. SR cannot go against logic. It is the other way round. I see that you keep pushing the rigidity argument, although I gave you a door system, where rigidity doesn't have any effect, because the doors stop in to each other. Why are you ignoring my comments? It looks like you are using it as an escape from the lack of arguments. Please, do not troll the topic.

I'm very sorry that you misinterpret my interaction in the discussion. Very often people on the Internet read the text with the voice intonation they usually use on the others. Perhaps you feel ridiculed not by me, but by the problem, which seems to be so obvious, but somehow was overlooked by such people like Einstein. In another conversation the last argument of one of the guys was "Do you think that you are cleverer than Einstein?" I understood your point in your previous comment, but was afraid that picking it up and unfolding it would be against the forum rules, and didn't want to get red point for trolling. Let's stay on the topic.

@J.C.MacSwell, you should understand one thing - logic first. The logic says that in this case a non-simultaneously moving doors cannot touch each other. That's a very simple logic. Don't try to find the touch point somewhere else. There is no such point for the non-simultaneously moving doors in the ladder FoR. If you argue this, no offense but I'll have to ignore your arguments. @studiot, whether you insert "apparent" for a paradox, or you think of it as a real paradox, does not change the fact, that its existence question the validity of a statement. However, we are not discussing the ladder paradox here, but just using it as a base for discussing the relativity of simultaneity. You can safely ignore the question whether the ladder passes the garage or not. Our focus is on the event which I introduced in the experiment. @Janus, I'm sorry, but your notes on the drawings and your sketches don't make any sense to me. I think that you are confused with my drawings. The doors stop when they meet at the red dot, and that event of meeting (touching) each other is what you should focus on. If you don't find that event in the ladder FoR, then there is something wrong with relativity of simultaneity. Good luck guys.

Incorrect. The sequence in the ladder FoR is "door closes and opens, then the other door closes and opens, then the other door... " and so on and so on. And I feel quite uncomfortable to be in an argument about this. I apologize beforehand if I don't answer some of the comments, but there is very little I can say from here on in this discussion. I'll keep an eye on it though.

Ha-ha Nice touch. I don't know what are you saying and which hinges do you mean. If you refer to the trapezoid sides of the doors, they'll never touch, because, in the ladder frame of reference, each door closes and opens while the other is open. That is required by the SR. It is explained in the original Ladder Paradox.

I don't understand your request. I provided everything you need. I gave you the Wikipedia image for the ladder FoR. What else do you need? You have to understand that in a frame of reference where simultaneity is missing, we cannot have a touching event. It's as simple as that. Irrelevant. Study the Ladder Paradox.

Do you even understand what are you saying I'm providing the proof, and you have to show the error.

Incorrect. Here is the image of the ladder FoR: The doors do not meet until the ladder is out. There is nothing to show. The doors do not touch in the ladder FoR. You show me because you are arguing that they'll touch.

OK, let see when the event happens in the ladder FoR.

Oh, we are going somewhere. Thank you. The point is that the doors can only touch when they are closing simultaneously and since there is no simultaneity in the ladder FoR, they'll never touch in that reference frame.

I don't think that you read my answers to you and the rest. There is no argument about the door touching on the short side of the trapezoid. THEY TOUCH! It is given as part of the experiment construct. You cannot say that the doors don't touch. THEY TOUCH. There is no walls or door frames to stop the doors. They meet and THEY TOUCH. And don't tell me that they'll crash into each other, please. I still try to figure out how the walls of the original Ladder Paradox resist such impacts from the doors

I don't get your point with the rigidity, but you should abandon the rigidity argument. I already said many times; this scenario can be replicated in many different ways without garage doors and ladder. But if you want it with doors, I can make them move vertically and still have the touch event. Or we can put two very short pins on the hinges, where the speed is the lowest or many, many different ways to satisfy your concerns. But your concerns must be about the logical output, not the technicalities, because the original Ladder Paradox does not meet any technical requirements, but is still a valid thought experiment. In my previous comment, I said that we can place the ladder outside the garage and lower down the speed of the doors to whatever speed suits you. The relativity of simultaneity does not depend on the speed of the doors. Even if they move with 100miles per hour, in the ladder FoR they'll still not close simultaneously. We are not interested in whether the ladder will pass through the garage, but whether the event is missing in its reference frame. In that context, we can create thousands of experiments to show that in one of the reference frames an event is missing.

OK. To make it even easier for that someone else, let's take the ladder out of the garage path. Let's assume that it doesn't go through the garage. For the ladder, the closing of the doors will still be not simultaneous due to its high speed. Now we can lower the speed of the closing doors, to meet your requirements for rigidity and door speed. Yet we'll still have a missing event in the ladder reference frame. And as I said, if the third event triggers a bomb, the garage will blow, but will still be intact in the ladder FoR. Why? Because in that FoR the event is missing.

"In the theory of relativity, it cannot happen" is not a valid argument, since we question the theory of relativity. I don't need to work out anything since the original Ladder Paradox experiment doesn't care about the technicality. Do you think that any door system can allow for a door to move with speed close to the speed of light, then instantly stop and move back with the same speed? I don't think so. Think of my experiment as constructed in order the doors to stop, when they touch at the red points. Think of the trapezoid part of the door as a solid on the whole length, if it will make it more comfortable for you from a techincal point of view. And instead of the doors stopping on a door frame, take it that they stop on each other, on that short side of the trapezoid, where the red dots are. And again, the experiment can be replicated in many different ways, not using doors, garage, and ladder. I just thought that this way of presenting it would be easier since everyone already knows the Ladder Paradox.

As I said in the OP, do not think of the event as "will not happen". It happens as part of the experiment construct; the doors stop when they meet at that red dot point. I don't see an added event as complexity which needs mathematical work. I just modified the doors of the experiment, which introduces one more event. The question is why the event is missing in the ladder FoR. What math can we use here?

OK, lets clear this one too. Here are the doors: The top image shows only the closed doors without the holding construction. (The holding construction is not of our interest.) The profile of the doors is painted black from outside and gray from inside. They are hanged on a single hinge rode, which you see in the middle between them. The red point is where the touching event occurs. The bottom image shows the doors (didn't draw the whole length) in open position with the red dots showing where the touching event will happen when the doors are closed. I'm not going to comment whether the SR is "internally consistent" and whether an experiment cannot disprove a theory. I'm interested in how a theory can explain a missing event in one of the reference frames.

Please accept my apologies. I didn't mean to offend anybody. The point is that I cannot explain it better than it is explained in the Wikipedia. But let's try. The question is; is it possible a longer than a garage ladder to fit between the simultaneously closed doors of the garage? SR answers YES, because of the length contraction. The answer is argued; it should not fit, because from the ladder FoR (frame of reference) the garage is even smaller. SR answers that it is possible due to the relativity of simultaneity; the doors of the garage do not close simultaneously in the ladder FoR. How that happens is shown in the right-hand image with the garage/ladder. Now, as you can see on the right-hand image (the ladder FoR) there is no touching event because the doors do not close simultaneously. However, it is against the laws of physics, because an event cannot be missing from one of the reference frames. Hence the discrepancy in the relativity of simultaneity and length contraction. Hope that now it's more clear.

You should study the Ladder Paradox then. Once you understand it, you'll understand the idea of the touching event, introduced by me. And then, use the second door system for your arguments.

The event does happen. That's how the experiment is constructed. When you clap your hands, you don't say that they don't clap. If you question the original experiment, then you are questioning the relativity of simultaneity. My addition of the experiment does not question and does not change the existing events. It only adds one more event. As I already said few times, use the second door system for your arguments. The original door system is to make it easy to understand the touching event in the door closing sequence. Please note that this scenario can be replicated in thousands of different variations not only with ladder and garage. I use the existing Ladder Paradox, to make it easy for you to understand.

Sorry if my OP is not clear enough for you, but it cannot be made clearer than that. The first image in the OP is an altered image from the original Wikipedia article for the Ladder Paradox, which I hoped will give you the idea for the third event "touching of the rodes". The second image is to avoid arguments on a technicality, as rigidity, fast closing doors etc. So, where the red dots are, the two doors touch; that is the event which is added to the original experiment. This touching event is missing in the ladder frame of reference, which is unacceptable. An event cannot be missing in one of the reference frames. It can occur in different space-time, but it should be present in both reference frames. If you understand my point, you'll understand why we don't need calculations. Sorry, that's irrelevant. Your arguments should deal with the third event.

Ignore the rods, and use the second doors system. No need for calculations here. The ladder paradox does not deal with calculations. It is a thought experiment accepted as an explanation of the relativity of simultaneity and length contraction. I only add a third event to the experiment, and you should focus your arguments on that. As long as you don't comment on the third event, your arguments are irrelevant.

I'm not producing a paradox I'm showing that the "Ladder Paradox" is impossible, therefore the relativity of simultaneity is impossible. It seems that you don't agree with the "Ladder Paradox" too because you're not arguing my point, but the technicality of the paradox itself. Are you aware that this paradox explains how the relativity of simultaneity works? If you want to argue my addition to the experiment, you should explain the missing event. The rest of the experiment does not contradict SR.

Did you read the OP until the end? Did you see the second image of the door system? I made it for people who already had your argument. Would you comment on the second door system, please?

I'm not trying to construct "an event that can happen simultaneously in both reference frames". I'm showing that an event is missing in one of the reference frames, which is unacceptable.

OK, that's why I asked to be excused. It just doesn't sound right to me. To my understanding, light cannot be observed in motion. We can only register its arrival. But again, I'm not familiar with the physics terminology.