Why Do Sound Signals Appear Simultaneous in Einstein's Train Thought Experiment?

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SUMMARY

The discussion centers on the perception of simultaneity in Einstein's train thought experiment when substituting sound signals for light flashes. Participants highlight that while all observers measure the speed of light as constant, the speed of sound is relative to the observer's motion through air. This leads to a lack of simultaneity for sound signals, as the observer moving at relativistic speeds would not perceive sound emitted from behind them. The confusion arises from the addition of velocities theorem, which does not apply to sound in the same way it does to light.

PREREQUISITES
  • Understanding of Einstein's theory of relativity
  • Familiarity with the concept of simultaneity in physics
  • Knowledge of the addition of velocities theorem
  • Basic principles of sound propagation and its dependence on the medium
NEXT STEPS
  • Study Einstein's theory of relativity in detail
  • Explore the concept of simultaneity in different reference frames
  • Research the addition of velocities theorem and its implications
  • Learn about sound propagation in various media and its relativity to the observer
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Physics students, educators, and anyone interested in the implications of relativity and the nature of simultaneity in different contexts.

pegasso
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why we do not observe any “lack of simultaneity” when we substitute sound signals for the light flashes in the “thought experiment” with a train moving past a platform (Einstein's lightning strike-train "thought experiment")?

this has troubled me for 5hours now. i don't know whether it is too advanced a question for me or whether i am blind to the answer.

can anyone help?

thanks :smile:
 
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All observers measure the same value for the speed of light, but they measure the speed of sound to depend on their velocities relative to the air.
 
the addition of velocities theorem was part of the reason for my confusion. i couldn't understand why simultaneity occurs when the sound signals are used? surely the observer in the reference frame moving at around c wouldn't hear the sound signal emitted from the point behind he/she?
 

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