Einstein's Train: Light Travel Time Explained

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SUMMARY

Einstein's Train illustrates the relativity of simultaneity through the example of lightning strikes A and B. In the Embankment frame, the strikes are simultaneous, but observer M' on the train sees the flash at B before A due to the effects of light travel time. When events are simultaneous in the Train frame, M' perceives them simultaneously, contradicting the Embankment frame's observations. Thus, the conclusion is that light travel time is a critical factor in determining the order of perceived events.

PREREQUISITES
  • Understanding of Einstein's theory of relativity
  • Familiarity with the concept of simultaneity in different reference frames
  • Knowledge of light travel time and its implications
  • Basic grasp of observer effects in physics
NEXT STEPS
  • Study the implications of simultaneity in special relativity
  • Explore the concept of light cones in spacetime diagrams
  • Learn about Lorentz transformations and their applications
  • Investigate real-world examples of relativistic effects in high-speed scenarios
USEFUL FOR

Students of physics, educators teaching relativity, and anyone interested in the implications of light travel time on perception and simultaneity.

David Lewis
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TL;DR
Einstein's Train -- M' will see B before A whether the events are simultaneous in Train frame or Embankment frame.
https://www.physicsforums.com/attachments/269029
Lightning strikes A and B simultaneously in the Embankment frame.
M' sees the flash at B before the one at A.
But if the flashes are simultaneous in the Train frame, does M' still see B before A?
 

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If the events are simultaneous in the train frame, then M' sees the events simultaneously(the light from the events reach him at the same time) and M doesn't.
 
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David Lewis said:
Summary:: Einstein's Train -- M' will see B before A whether the events are simultaneous in Train frame or Embankment frame.

But if the flashes are simultaneous in the Train frame, does M' still see B before A?
No. Why would they?
 
To answer the question in the title ("Does Einstein's train account for light travel time?"):
Yes. The entire argument is based on considering the consequences of light travel time between the strikes and the observers' eyes.
 
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If the flashes are simultaneous in the Train frame, does M' see B before A?
Dale said:
No. Why would they?
Because when the light reaches M', he will be closer to B than to A.
I forgot, however, that when an observer sees two equidistant events happen at the same time then they are simultaneous in his frame.
 
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