- #1

Hak

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I have always had certain difficulties in correctly understanding the theory of special relativity; I often apply it to certain situations and they fall apart...

Imagine there is a rectangular object placed with its long sides parallel to the ground and its short sides perpendicular to it, moving at a certain constant speed with the same direction as the long sides. There are 2 observers, one on the object (moving with it) and the other outside, on the 'stationary' earth. From the centre of the rectangle, 2 photons depart in the direction of motion, one in one direction, the other in the opposite direction, and exit the 'rectangle'.

According to the observer in solidarity with the rectangle, in order to exit the rectangle, the photons take 2 paths with the same length, i.e. half the long side of the rectangle (since the photons start from the centre). According to the (2nd) postulate of special relativity, the speed of light is always C for every reference system, so the 2 photons take the same time to exit the rectangle, i.e. L/C (L= half the long side of the rectangle), so they exit at the same time.

According to the external observer, the photon that is going in the same direction as the rectangle is moving, has to travel a greater distance than L to exit the rectangle, because in the meantime the edge of the rectangle that the photon must pass through to exit it is moving in its own direction, moving away from where the photon started. On the other hand, the other photon, moving in the opposite direction, and exit the 'rectangle'.

According to the observer in solidarity with the rectangle, the photons take 2 paths with the same length, i.e. half the long side of the rectangle (since the photons start from the centre), to exit the rectangle. According to the (2nd) postulate of special relativity, the speed of light is always C for each reference system, therefore the 2 photons take the same time to exit the rectangle, i.e. L/C (L= half the long side of the rectangle), so they exit at the same time.

According to the external observer, the photon that is going in the same direction as the rectangle is moving, has to travel a greater distance than L to exit the rectangle, because in the meantime the edge of the rectangle that the photon must pass through to exit it is moving in its own direction, moving away from where the photon started. On the other hand, the other photon, which is moving in the opposite direction to the speed of the rectangle, will have to travel a shorter distance than L, since the edge of the rectangle that it must pass through is coming towards it, approaching the place where the photon started. The speed of the 2 photons must be the same, C, so the first photon, having to travel a greater distance, will take longer to exit than the other photon, which has to travel a shorter distance. So, for the external observer, the two photons leave at two different times... but for the internal observer, they leave at the same time!

Thus we have 2 different universes, one in which the photons are one in which the photons came out at the same time, and another in which they came out at 2 different times. So I asked my physics professor for an explanation, and he roughly replied that, as becoming progresses, things settle down, and it just seems that the universes are different just because the observers are different.

Subsequently, another idea came to me. Let us place 2 circles at the ends of the rectangle, near the short sides, just where the photons come out; these circles are divided into many (numbered) segments and are arranged in such a way as to accommodate the photons in their segmented compartments when they hit them. We rotate the two circles, connecting them (with a tube) in such a way that they rotate together, so that when one circle is in a position to receive the photon coming at it from the rectangle in a given segment, the other circle also receives a possible photon in the same segment.

With such a device, the observer integral with the rectangle, seeing that the photons leave the rectangle at the same instant, captures the 2 photons, in the 2 rotating circles, always in compartments with the same numbering. On the other hand, for the external observer, seeing that he sees the 2 photons leave at 2 different instants, by arranging everything appropriately, the 2 photons will be captured by 2 compartments with different numbering, since in the time lapse that the lagging photon takes longer to leave, the circle that must capture it still rotates a little bit by changing segments. The rectangle stops and the 2 observers meet: one shows the other that the photons are in the same segment (or at least shows the segments with more energy, due to the photon that hit them), the other that they are in different segments... but while there are 2 observers, the reality (at least for sympathetic observers) is 1!

I hope I have been sufficiently understandable... if you find any missteps I will be very grateful: I have not found a solution for some time. Thank you very much.

Imagine there is a rectangular object placed with its long sides parallel to the ground and its short sides perpendicular to it, moving at a certain constant speed with the same direction as the long sides. There are 2 observers, one on the object (moving with it) and the other outside, on the 'stationary' earth. From the centre of the rectangle, 2 photons depart in the direction of motion, one in one direction, the other in the opposite direction, and exit the 'rectangle'.

According to the observer in solidarity with the rectangle, in order to exit the rectangle, the photons take 2 paths with the same length, i.e. half the long side of the rectangle (since the photons start from the centre). According to the (2nd) postulate of special relativity, the speed of light is always C for every reference system, so the 2 photons take the same time to exit the rectangle, i.e. L/C (L= half the long side of the rectangle), so they exit at the same time.

According to the external observer, the photon that is going in the same direction as the rectangle is moving, has to travel a greater distance than L to exit the rectangle, because in the meantime the edge of the rectangle that the photon must pass through to exit it is moving in its own direction, moving away from where the photon started. On the other hand, the other photon, moving in the opposite direction, and exit the 'rectangle'.

According to the observer in solidarity with the rectangle, the photons take 2 paths with the same length, i.e. half the long side of the rectangle (since the photons start from the centre), to exit the rectangle. According to the (2nd) postulate of special relativity, the speed of light is always C for each reference system, therefore the 2 photons take the same time to exit the rectangle, i.e. L/C (L= half the long side of the rectangle), so they exit at the same time.

According to the external observer, the photon that is going in the same direction as the rectangle is moving, has to travel a greater distance than L to exit the rectangle, because in the meantime the edge of the rectangle that the photon must pass through to exit it is moving in its own direction, moving away from where the photon started. On the other hand, the other photon, which is moving in the opposite direction to the speed of the rectangle, will have to travel a shorter distance than L, since the edge of the rectangle that it must pass through is coming towards it, approaching the place where the photon started. The speed of the 2 photons must be the same, C, so the first photon, having to travel a greater distance, will take longer to exit than the other photon, which has to travel a shorter distance. So, for the external observer, the two photons leave at two different times... but for the internal observer, they leave at the same time!

Thus we have 2 different universes, one in which the photons are one in which the photons came out at the same time, and another in which they came out at 2 different times. So I asked my physics professor for an explanation, and he roughly replied that, as becoming progresses, things settle down, and it just seems that the universes are different just because the observers are different.

Subsequently, another idea came to me. Let us place 2 circles at the ends of the rectangle, near the short sides, just where the photons come out; these circles are divided into many (numbered) segments and are arranged in such a way as to accommodate the photons in their segmented compartments when they hit them. We rotate the two circles, connecting them (with a tube) in such a way that they rotate together, so that when one circle is in a position to receive the photon coming at it from the rectangle in a given segment, the other circle also receives a possible photon in the same segment.

With such a device, the observer integral with the rectangle, seeing that the photons leave the rectangle at the same instant, captures the 2 photons, in the 2 rotating circles, always in compartments with the same numbering. On the other hand, for the external observer, seeing that he sees the 2 photons leave at 2 different instants, by arranging everything appropriately, the 2 photons will be captured by 2 compartments with different numbering, since in the time lapse that the lagging photon takes longer to leave, the circle that must capture it still rotates a little bit by changing segments. The rectangle stops and the 2 observers meet: one shows the other that the photons are in the same segment (or at least shows the segments with more energy, due to the photon that hit them), the other that they are in different segments... but while there are 2 observers, the reality (at least for sympathetic observers) is 1!

I hope I have been sufficiently understandable... if you find any missteps I will be very grateful: I have not found a solution for some time. Thank you very much.

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