Can you explain Einstein's train metaphor/thought experiment.
Are you referring his thought experiment dealing with the Relativity of Simultaneity?
Yes, Relativity of Simultaneity
it is impossible to discuss here. i will scan and send my hand calculation about this train. in this experiment it was revealed that time is relative for each person :)
Check it out: http://en.wikipedia.org/wiki/Relativity_of_simultaneity#The_train-and-platform_thought_experiment
He explains it himself, here:
You could modify his example to a simpler one (IMHO) as follows.
You are in the middle of the train and take a picture with flashlight, light of which reaches the front and rear of the train. These light pulses that are received at the front and the rear of the train are simultaneous by definition in a standard coordinate system in which the train is in rest.
Now suppose that the train was passing a railway station, and there the flash light was also observed. According to the railway station's reference system, while flash light propagated towards the rear, the clock in the rear traveled towards the light; thus this took less time. And while flash light propagated towards the front, the clock in the front traveled away from it, so that took more time. As a result, the light reached the front clock later than the rear clock, according to the time counting of the railway station.
PS. I now see that that is also the way the Wikipedia article presents it, and with pictures; it's really easy.
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