- #1
roineust
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Here is my question, starting from a suggested experiment that reminds a known example that Einstein gave about special relativity including a moving train, two mirrors inside the train and a light beam reflected between the mirrors (this suggested thought experiment described here only reminds the historically well known thought experiment –please note critical differences):
1. Let's question how to measure and compare measurements for an amount of time that it takes a light beam to travel from a bottom mirror to a top mirror in a train, once when the train is not moving (stationary at dock) and once when its moving at constant speed relative to dock (when measured only from within the train). As much as I understand this amount of time has got to be the same in both cases because the speed of light is constant at any direction and relative speed, while regarding the height of the train - there exists only horizontal length contraction, as seen from outside the train (in the same direction that the train is moving), so anyway there is no vertical length contraction from within the train. It seems that the time it takes light to travel from top to bottom mirror or from bottom to top mirror when looked at from inside the train is the same - doesn't matter if train is moving or not.
I think it's important to repeat that point: we are measuring from within the train, and not what is seen from outside the train. Measuring once when the train is not moving and once when the train is moving. The measurement is made by dividing the height of the train by the speed of light (constant at any speed or direction).
2. Suppose every time the light beam hits the top or the bottom mirror in the train, there is a mechanism that changes the light color a little bit.
3. This light apparatus in the train will be a clock for us in here suggested experiment.
One more thing that should be emphasized here, is that every time the light beam hits the bottom or top mirror, it registers a counter bottom and counter top photo-electric mechanisms with +1 hit.
4. If we assume as described in bullet 1, that time dilation dose not occur in the duration of the travel that the light beam makes from bottom mirror to top mirror of the train (in other words let's put aside in this experiment the concept of: 'looking at the light beam in the train from outside') - as measured only from within the train once when not moving and once when moving. As well we know time dilation must occur in the apparatus as a whole (assuming time dilation at constant speed was experimentally proved) - Then time dilation must occur somewhere in the parts and components of this clock apparatus that change light beam color, and other parts that make the light bounce back, and in the parts that register the number of light hits – but time dilation does not occur in that clock component built with a vacuum tube where light itself bounces - because the assumption here is that light itself can not undergo time dilation.
5. If we add one more condition here, and it is that changing the color of light beam and bouncing it back is a faster process than sending a signal over the wires of the apparatus towards the counter (say these wires are long enough), then:
6. When this experiment is made, results should be as following - as the train is not in motion relative to dock, and after running the clock for a while, the counter will show a certain number in accordance with a certain light color, and when the train is moving relative to the dock, the exact same number that will show on the clock counter must be (according to all above assumptions) coupled with a different light color.
This is because while the travel of light from the upper mirror to the bottom mirror takes the same amount of time (e.g. X seconds in both cases), in other parts of this clock apparatus, time dilation does make a difference (e.g. changing color of light beam and bouncing the light back takes 2X when train is stationary, and 4X when train is moving, registering light hits takes 10X when train is stationary, and 20X when train is moving). The result is that if we stop the light hit counters of the moving train and the stationary train at the same counter numbers, the corresponding light colors will not be the same.
7. If such results will appear this might be a serious problem! That is because, although such results still show in a way the validity of time dilation, they enable experimentally to say if the train is moving or not, without looking out of the window - which brings physics back 105 years to the necessity of hypothesizing some sort of ether.
8. If none of the above will happen, and when counters will be stopped at the same number, corresponding light colors will be the same, then my question is, won't such results represent a situation, in which light itself undergoes time dilation?Diagram 1: 20X/5X=4 but 10X/3X=3.33 Now, here is a simplification of the 'Bouncing light' experiment:
While there is no time dilation effect on the wires, there is time dilation effect on each cycle of crystal vibration, as a result of the electric pulse, therefore when the apparatus was adjusted to have light sources turn on together in stationary apparatus, the exact same arrangement of wires, crystal and light sources, will not have the light sources turn on together when in the moving apparatus.Diagram 2: 2X+1X+2X=5X but 2X+2X+2X=6X
1. Let's question how to measure and compare measurements for an amount of time that it takes a light beam to travel from a bottom mirror to a top mirror in a train, once when the train is not moving (stationary at dock) and once when its moving at constant speed relative to dock (when measured only from within the train). As much as I understand this amount of time has got to be the same in both cases because the speed of light is constant at any direction and relative speed, while regarding the height of the train - there exists only horizontal length contraction, as seen from outside the train (in the same direction that the train is moving), so anyway there is no vertical length contraction from within the train. It seems that the time it takes light to travel from top to bottom mirror or from bottom to top mirror when looked at from inside the train is the same - doesn't matter if train is moving or not.
I think it's important to repeat that point: we are measuring from within the train, and not what is seen from outside the train. Measuring once when the train is not moving and once when the train is moving. The measurement is made by dividing the height of the train by the speed of light (constant at any speed or direction).
2. Suppose every time the light beam hits the top or the bottom mirror in the train, there is a mechanism that changes the light color a little bit.
3. This light apparatus in the train will be a clock for us in here suggested experiment.
One more thing that should be emphasized here, is that every time the light beam hits the bottom or top mirror, it registers a counter bottom and counter top photo-electric mechanisms with +1 hit.
4. If we assume as described in bullet 1, that time dilation dose not occur in the duration of the travel that the light beam makes from bottom mirror to top mirror of the train (in other words let's put aside in this experiment the concept of: 'looking at the light beam in the train from outside') - as measured only from within the train once when not moving and once when moving. As well we know time dilation must occur in the apparatus as a whole (assuming time dilation at constant speed was experimentally proved) - Then time dilation must occur somewhere in the parts and components of this clock apparatus that change light beam color, and other parts that make the light bounce back, and in the parts that register the number of light hits – but time dilation does not occur in that clock component built with a vacuum tube where light itself bounces - because the assumption here is that light itself can not undergo time dilation.
5. If we add one more condition here, and it is that changing the color of light beam and bouncing it back is a faster process than sending a signal over the wires of the apparatus towards the counter (say these wires are long enough), then:
6. When this experiment is made, results should be as following - as the train is not in motion relative to dock, and after running the clock for a while, the counter will show a certain number in accordance with a certain light color, and when the train is moving relative to the dock, the exact same number that will show on the clock counter must be (according to all above assumptions) coupled with a different light color.
This is because while the travel of light from the upper mirror to the bottom mirror takes the same amount of time (e.g. X seconds in both cases), in other parts of this clock apparatus, time dilation does make a difference (e.g. changing color of light beam and bouncing the light back takes 2X when train is stationary, and 4X when train is moving, registering light hits takes 10X when train is stationary, and 20X when train is moving). The result is that if we stop the light hit counters of the moving train and the stationary train at the same counter numbers, the corresponding light colors will not be the same.
7. If such results will appear this might be a serious problem! That is because, although such results still show in a way the validity of time dilation, they enable experimentally to say if the train is moving or not, without looking out of the window - which brings physics back 105 years to the necessity of hypothesizing some sort of ether.
8. If none of the above will happen, and when counters will be stopped at the same number, corresponding light colors will be the same, then my question is, won't such results represent a situation, in which light itself undergoes time dilation?Diagram 1: 20X/5X=4 but 10X/3X=3.33 Now, here is a simplification of the 'Bouncing light' experiment:
While there is no time dilation effect on the wires, there is time dilation effect on each cycle of crystal vibration, as a result of the electric pulse, therefore when the apparatus was adjusted to have light sources turn on together in stationary apparatus, the exact same arrangement of wires, crystal and light sources, will not have the light sources turn on together when in the moving apparatus.Diagram 2: 2X+1X+2X=5X but 2X+2X+2X=6X
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