Trying to Understand Light in Motion: A Frustrating Puzzle

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The discussion centers on the complexities of understanding how light from two sources reaches a passenger on a moving train, particularly in relation to the principles of relativity. It highlights that while light travels at the same speed for all observers, the timing of when it reaches the passenger can differ based on the frame of reference used for synchronization. When synchronized with the train's frame, both light pulses can appear to hit the passenger simultaneously, whereas in the ground frame, they arrive at different times due to the train's motion. The conversation also touches on the mathematical representations of four-velocities and the implications of spacetime geometry on the perception of simultaneity. Ultimately, the discussion illustrates the nuanced nature of light propagation and observer-dependent effects in relativistic contexts.
  • #391


solarflare said:
this was posted to show the videos worldline
Once again, you have switched scenarios. This diagram is for the standard scenario in which the lightning strikes are simultaneous in the platform frame.

the strikes are along the X axis both at t = 0
Yes, in the platform frame.

as they occur on the train - they must be simultaneous
The fact that they occur 'on the train' is irrelevant. They are simultaneous in the platform frame, not the train frame.

the light then travels from the sources to the platform observer at t = 4
Sure, it takes time for the light to travel to the platform observer.

the lines also cross the t prime axis but the x prime line is not used to show where they cross on the t prime line
You should be able to draw in the lines to see where and when the events (the lightning strikes) happen in the train frame.
 
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  • #392


it is not irrelevant when the graph says they occur on the train simultaneously

and again the lines cross t prime from the source on the x-axis

if you want to say that t prime is relevant then the source of the lines that cross t prime must also be relevant
 
  • #393


This thread is obviously going nowhere (and very slowly at that). So it's time to shut it down.

Solarflare: All your questions have been answered several times over. Repeating the same thing isn't going to help. If you're serious, I suggest getting an intro book on relativity. (Or you can read Einstein's own words--see George's link.) Then you can go back and read through this thread again.

Thanks to everyone who contributed their time and effort to this thread.
 

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