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Hi, I have been reading and watching a lot of physics lately but I have come across this problem.

I have the basics of special relativity down, and it all seems clear to me. This is not in question to me. For example, I am reading a book on string theory by Brain Greene, and in it he covers relativity. All the explanations are clear and I can easily understand exactly what logic he is using and how it works.

However upon reading Einsteins 1920 publication on relativity (which you can read here for reference: https://www.bartleby.com/173/

I am having a trainload of problems

Chapter 7 became extremely aggravating as I spent about an hour reading the same page over 10 times, and feeling everything contradicted or that the explanations were terribly given. however I was able to find a way to just write it off as bad explanations,

but then Chapter 9 got worse, as it just seemed downright wrong, and I can't find a way of looking at it that explains it. So help me out here..

This is the passage in question:

My problems comes with the statement: "Hence the observer will see the beam of light emitted from

Um, no he wouldn't?

My thinking is this: if the speed of light is constant for all observers, then let us imagine from the perspective of M' (the man on the train) he is stationary while A & B are moving by him. First A passes him, and then when he is in the middle the lightning strikes and pulses light toward him. A & B continue moving by as the light travels, but since he was in the middle (M) at the moment they pulsed, from his view the beams both travel to him at the same exact rate accross the equal distance to him, since there will be no added (or subtracted) velocity due to the points (A&B) motion past him. If there was, that would mean that he could rush towards an object and measure the speed of light as c+v where v is his own velocity relative to it, (or it to him.) hence, VISUALLY at the very least he would see both pulses at the same moment no matter how fast he goes by the embankment?

I thought this over and over, I've searched the text for some misunderstanding, I cant find anything, what am I missing? My only thought was that maybe this was described from the perspective of the embankment watching the observer on the train, but in the last two sentences the text makes it clear that they mean the observers from their own perspective on the train.

My second problem is this:

If you described this experiment say with cannons instead of lightning, and had two cannons aimed at M, and had them both fire at the moment lightning strikes them, then this experiments description would hold true, if we considered the arrival of the cannonballs at the observers to be our method of judging simultanaety of firing. This would be because the observer on the train would be adding his velocity towards the cannonball in front of him to its speed toward him, thus it would fly by his face before the cannonball behind him reaches him, just as this chapter describes what light supposedly would do?

But this scenario I've invented is a description involving objects that can be described in a Newtonian manner, (adding velocities, etc) therefore what is the point of this experiment in trying to undermine our Newtonian notions of time? We all know that velocities add to an object in motion so if light did the same thing it would only demonstrate and reinforce the Newtonian dynamics.

I can't possibly think that Relativity is wrong, nor do I, nor can I think that this book wasn't carefully thought through and read and analyzed by many people, yet I can't for the life of me figure out what I'm missing.

I have the basics of special relativity down, and it all seems clear to me. This is not in question to me. For example, I am reading a book on string theory by Brain Greene, and in it he covers relativity. All the explanations are clear and I can easily understand exactly what logic he is using and how it works.

However upon reading Einsteins 1920 publication on relativity (which you can read here for reference: https://www.bartleby.com/173/

I am having a trainload of problems

Chapter 7 became extremely aggravating as I spent about an hour reading the same page over 10 times, and feeling everything contradicted or that the explanations were terribly given. however I was able to find a way to just write it off as bad explanations,

but then Chapter 9 got worse, as it just seemed downright wrong, and I can't find a way of looking at it that explains it. So help me out here..

This is the passage in question:

UP to now our considerations have been referred to a particular body of reference, which we have styled a “railway embankment.” We suppose a very long train travelling along the rails with the constant velocity v and in the direction indicated in Fig. 1. People travelling in this train will with advantage use the train as a rigid reference-body (co-ordinate system); they regard all events in reference to the train. Then every event which takes place along the line also takes place at a particular point of the train. Also the definition of simultaneity can be given relative to the train in exactly the same way as with respect to the embankment. As a natural consequence, however, the following question arises: | 1 |

Are two events (e.g. the two strokes of lightning A and B) which are simultaneous with reference to the railway embankment also simultaneous relatively to the train? We shall show directly that the answer must be in the negative.FIG. 1. | 2 |

When we say that the lightning strokes A and B are simultaneous with respect to the embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A —> B of the embankment. But the events A and B also correspond to positions A and B on the train. Let M' be the mid-point of the distance A —> B on the travelling train. Just when the flashes of lightning occur, this point M' naturally coincides with the point M, but it moves towards the right in the diagram with the velocity v of the train. If an observer sitting in the position M’ in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A. Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A. |

My problems comes with the statement: "Hence the observer will see the beam of light emitted from

*B*earlier than he will see that emitted from*A."*Um, no he wouldn't?

My thinking is this: if the speed of light is constant for all observers, then let us imagine from the perspective of M' (the man on the train) he is stationary while A & B are moving by him. First A passes him, and then when he is in the middle the lightning strikes and pulses light toward him. A & B continue moving by as the light travels, but since he was in the middle (M) at the moment they pulsed, from his view the beams both travel to him at the same exact rate accross the equal distance to him, since there will be no added (or subtracted) velocity due to the points (A&B) motion past him. If there was, that would mean that he could rush towards an object and measure the speed of light as c+v where v is his own velocity relative to it, (or it to him.) hence, VISUALLY at the very least he would see both pulses at the same moment no matter how fast he goes by the embankment?

I thought this over and over, I've searched the text for some misunderstanding, I cant find anything, what am I missing? My only thought was that maybe this was described from the perspective of the embankment watching the observer on the train, but in the last two sentences the text makes it clear that they mean the observers from their own perspective on the train.

My second problem is this:

If you described this experiment say with cannons instead of lightning, and had two cannons aimed at M, and had them both fire at the moment lightning strikes them, then this experiments description would hold true, if we considered the arrival of the cannonballs at the observers to be our method of judging simultanaety of firing. This would be because the observer on the train would be adding his velocity towards the cannonball in front of him to its speed toward him, thus it would fly by his face before the cannonball behind him reaches him, just as this chapter describes what light supposedly would do?

But this scenario I've invented is a description involving objects that can be described in a Newtonian manner, (adding velocities, etc) therefore what is the point of this experiment in trying to undermine our Newtonian notions of time? We all know that velocities add to an object in motion so if light did the same thing it would only demonstrate and reinforce the Newtonian dynamics.

I can't possibly think that Relativity is wrong, nor do I, nor can I think that this book wasn't carefully thought through and read and analyzed by many people, yet I can't for the life of me figure out what I'm missing.

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