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The second animation is not reflecting the truth of the Einstein's "thought experiment"

He stated clearly: "two lightning bolts strike simultaneusly both ends of the boxcar leaving the marks on the car and on the ground".

From the perspective of the observer on the embankment. You are completely missing the point of the thought experiment if you think this means the observer on the train also observed the lightning bolt strikes have occurred simultaneously. To the observer on the train, the lightning bolt strikes occur at different times. Simultaneity is relative.

Posted
The second animation is not reflecting the truth of the Einstein's "thought experiment"

He stated clearly: "two lightning bolts strike simultaneusly both ends of the boxcar leaving the marks on the car and on the ground". If the strikes occurred at the same time, detectors at both ends of the boxcar would record the same time of the strikes. The animation is quite nice but totaly untrue, it does not reflect the "thought experiment" devised by Einstein. He said that the boxcar will be "hastening"towards the signal from the front, while "receding"from the signal from the back. That was the contradiction to his own postulate that the speed of light is constant, regardless of the frame of reference

The hastening to and receding from is only in the frame of reference of the embankment. In his own frame, he is not, that is the whole point.

 

 

The second animation shows entirely different scenario, it is just not from the same experiment.

 

Exact same scenario, just from the other frame.

 

In the quote from Einstein he says:

 

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.

 

Note the part in bold. To understand what he means by this you have to go back to where he defines simultaneity in section VIII: "On the Idea of Time in Physics".

 

There he uses an observer placed halfway between two lightning strikes and states that the lightning strikes are considered simultaneous in the frame of this observer if the observer sees them at the same time. This true because of the stipulation that the light from one event travels at the same speed as the other relative to the frame of the observer.( This is the second postulate of Relativity)

 

So when he talks about the definition of simultaneity being the same for the train as for the embankment, this is what he means; That an observer at the midpoint of the train would see the light from events occurring simultaneously at the two ends at the same time.

 

Now of the two observers in the thought experiment only one of these fulfills both requirements for simultaneity of the lightning strikes, and that is the embankment observer. He is halfway between the lightning strikes and see them at the same time. The train observer, only fulfills one requirement in his frame. He is halfway between the ends of the points on the train where the lightning strikes, but he does not see the strikes at the same time. Ergo, the lightning strikes were not simultaneous in his frame.

 

On your first animation the flash reaches the front and the back of the boxcar at the same moment. The detectors at both ends would be activated exactly at the same time. If they were emitting the light, say one red and one blue, both red and blue rays should reach the middle of the boxcar simultaneusly.

 

You are assuming a priori, that simultaneous in the embankment frame is the same as simultaneous in the train frame.

 

We already know that in the embankment frame, the light from the front strike hits the train observer first. Now you are saying That light emitted by lightning detectors at the ends of the train would reach the middle of the train at the same time. But if that were true, then one of the following must happen.

 

1. Assuming that simultaneity is absolute between the frames, then the red and blue lights must reach the middle of the train at the same time according to the embankment also. But for that to be true, the Red and blue lights would have to travel at different speeds relative to each other, and at different speeds than the light from the lightning. This violates the second postulate, and is contrary to every experiment done with light.

 

2. Both the light from the Red and Blue lights and the lightning strikes reach the middle of the train at the same time in the train frame. The train observer sees the flashes at the same time, yet according to the embankment observer, one flash reaches him first. This leads to a physical contradiction between the frames.

For example, in the middle of the train we have a device which consists of a double sided strip of photographic film being fed past a slit. The film is sensitive to a particular frequency of light in the lightning flashes.

Now in the train frame, the flashes reaches the film at exactly the same time, and exposes the two sides of the film through the slits at the same time. Thus the marks left on the film will be matched up. However according to the embankment frame, the front flash arrives first, and exposes one side of the film through the slit. The film then continues to feed past the slit, until the second flash arrives exposing the other side of the film through its slit. Thus you will have the marks on the film offset from each other. But the same piece of film can't have the marks both line up and be offset from each other.

 

A more dramatic example is a bomb designed to detonate if the light from both flashes reach it at the same time. In the train frame, they do and bomb explodes, in the embankment frame, they don't and the bomb doesn't. The train cannot have both blown up and have not blown up.

 

The only way to avoid such physical contradictions, and preserve the postulates of Relativity is by having the lightning strikes not occurring simultaneously in the train frame, as shown in the animations I provided.

 

The other thing that you must consider is that this thought experiment has undergone scrutiny by countless scientists for decades and passed muster.

 

What are the odds that all them missed what would be such a blatant error for so long, compared to the odds that you, a single laymen, have simply misinterpreted it?

Posted

This original Einstein's "thought experiment", which is somewhat different to your interpretation:

"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 1 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. "

Einstein maintained that because middle point M inside the train was moving towards the front flash as well as receding from rear flash, both signal will not arrive in the midpoint at the same time. BUT BOTH FLASHES HAVE OCCURRED AT THE SAME TIME IN RESPECT TO THE TRAIN!!! Just the signals from both ends will not meet in the midpoint M.This obvious contradiction to his own theory.

Einstein's explanation of time dilation is also seriously flawed. In his explanation the light was reflected from the mirror on the ceiling inside boxcar travelling in horizontal direction in regard to stationary observer. It was concluded that even if the light was emitted perpendicular to the mirror, for external observer it would appear to be travelling on angle. Because speed of light is constant, therefore time would have to be longer. But what if there are two light rays , one vertical and one directed towards the back of the boxcar on such angle that external observer would perceive it as vertical, emitted simultaneously.For external observer the vertical ray (in his frame of reference) would travel longer, than slanted ray.

Another illogical paradox:the twin paradox. Einstein's reasoning was that the twin brother which stayed at home would age more than the travelling one.Somebody pointed out that because there is no absolute reference frame, we could say that the brother which stayed at home was actually travelling in reference to the astronaut twin. Some scientists argue however that the travelling brother would have to accelerate, deccelerate and turn around,therefore his situation would be entirely different. Now let's imagine there are triplets instead of twins and two of them started their journey towards the star. After reaching cruising speed one of them decided to return to the Earth.He would undergo the same acceleration, deceleration and change in direction as the other one which has completed his journey. Now how would you explain him ageing more than the one who went to the star?

There are also some more points, like theory of light which can be explain differently, (the light could be explained using wave theory; I can prove that exponentially decaying wave has its total energy proportional to its frequency).

Posted
This original Einstein's "thought experiment", which is somewhat different to your interpretation:

"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 1 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. "

Einstein maintained that because middle point M inside the train was moving towards the front flash as well as receding from rear flash, both signal will not arrive in the midpoint at the same time. BUT BOTH FLASHES HAVE OCCURRED AT THE SAME TIME IN RESPECT TO THE TRAIN!!! Just the signals from both ends will not meet in the midpoint M.This obvious contradiction to his own theory.

Once again, there is no contradiction within the theory, the apparent contradiction comes from your own misinterpretation. You are assuming that "the lightning strikes hit the ends of the train simultaneously in the ground frame" automatically means "the lightning strikes hit the ends of the train simultaneously in the train's frame". You are assuming a conclusion for the thought experiment before you even start. Einstein did not assume this, but instead designed the thought experiment to test this idea, while adhering to the postulates of his theory. His conclusion was that if you hold the postulates as true, then this conclusion cannot be maintained; silumtaneous in the ground frame does not always equal simulataneous in the train's frame.

 

Einstein's explanation of time dilation is also seriously flawed. In his explanation the light was reflected from the mirror on the ceiling inside boxcar travelling in horizontal direction in regard to stationary observer. It was concluded that even if the light was emitted perpendicular to the mirror, for external observer it would appear to be travelling on angle. Because speed of light is constant, therefore time would have to be longer. But what if there are two light rays , one vertical and one directed towards the back of the boxcar on such angle that external observer would perceive it as vertical, emitted simultaneously.For external observer the vertical ray (in his frame of reference) would travel longer, than slanted ray.

In such an experiment, you have to take length contraction into account. Also, in order to avoid also dealing with Relativity of Simulataneity, you need to consider the total round trip time (source to mirror and then back to source. You also have to be sure that the distance between source and both mirrors are the same in their frame, so that in this frame, the two pulses take equal times to return. Then we can examine if a light pulse launched at a different angle would return at a different time according to an external observer to which the apparatus is moving.

 

I have already done this analysis in another thread. Here's the link:

 

http://www.scienceforums.net/forum/showpost.php?p=185310&postcount=68

 

It shows that you get the same time dilation for light reflected at any angle.

 

Another illogical paradox:the twin paradox. Einstein's reasoning was that the twin brother which stayed at home would age more than the travelling one.Somebody pointed out that because there is no absolute reference frame, we could say that the brother which stayed at home was actually travelling in reference to the astronaut twin. Some scientists argue however that the travelling brother would have to accelerate, deccelerate and turn around,therefore his situation would be entirely different. Now let's imagine there are triplets instead of twins and two of them started their journey towards the star. After reaching cruising speed one of them decided to return to the Earth.He would undergo the same acceleration, deceleration and change in direction as the other one which has completed his journey. Now how would you explain him ageing more than the one who went to the star?

 

It is not just the acceleration that counts, but the separation between clocks also. Thus when the one twin decelerates upon reaching cruising speed, he is not as far from Earth as his brother will be upon completing his journey. This results in his determination the the Earth ages less rapidly during his acceleration than it will for his brother. In essence, it goes back to the Relativity of Simulataneity.

 

You are not going to find a flaw in Relativity this way. It has been gone over with a fine toothed comb by some the best minds there are. The logic is air-tight and entirely self-consistant. Just because you have trouble following it doesn't make it wrong.

 

The only way to possibly prove Relativity wrong is to produce results from an actual physical observation that are different from what Relativity predicts.

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