Relativity of Simultaneity Questions

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Discussion Overview

The discussion revolves around the relativity of simultaneity, exploring how different observers perceive the timing of events in the context of special relativity. Participants examine scenarios involving observers at different distances from simultaneous events and how motion affects their conclusions about simultaneity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that observer A and observer B would agree on simultaneity when motion is not involved, but this changes with motion.
  • One participant questions whether observer B would document events based on observation or conclusion, emphasizing the role of understanding the finite speed of light.
  • Another participant suggests that the conclusions drawn by observers depend on their frame of reference and whether they choose to consider themselves at rest or in motion.
  • There is discussion about the idealized nature of events like lightning strikes and how they are treated in spacetime diagrams.
  • Some participants note that time dilation and other relativistic effects will come into play later in the discussion.
  • One participant expresses confusion about how different observers conclude simultaneity differently, suggesting a need for mathematical exploration.
  • There is mention of the Lorentz transformation as a tool to understand the relationship between time, distance, and speed in relativistic contexts.

Areas of Agreement / Disagreement

Participants generally agree that simultaneity is not absolute and that different observers can conclude different timings for the same events based on their relative motion. However, there is no consensus on the specifics of how these conclusions are drawn or the implications of time dilation at this stage of the discussion.

Contextual Notes

Participants acknowledge that the discussion involves complex concepts that are not fully resolved, including the implications of time dilation and the use of different frames of reference. The mathematical details and assumptions regarding units in the Lorentz transformation are also points of clarification.

Who May Find This Useful

This discussion may be useful for individuals interested in the foundational concepts of special relativity, particularly those exploring the implications of simultaneity and the mathematical frameworks used to analyze relativistic scenarios.

  • #61
mucker said:
I've ordered the book!
What you describe above is how I currently understand what a ref frame is - so I don't see how you concluded that I don't understand what one is. Can you please indicate what I have said to make you think this? I am wondering if I am just not explaining myself correctly.
In any case, the important thing is to learn and progress. If you already understand something, then that's fine.
 
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  • #62
PeroK said:
You can move relative to a source of light, but you can't move relative to where light was emitted. Or, at least, not in your own rest frame.
Indeed, and maybe that's also a problem of a lot of confusion of students starting to learn relativity. One should not talk about the "invariance of the speed of light" but rather say the speed of light, as measured by an inertial observer, is independent of the velocity of the light source relative to that observer. Einstein formulated it in this clear and unambigous way already in his 1905 seminal paper. Why textbook writers haven't kept this good tradition, I can't say. The only sin in the 1905 paper is the introduction of "relativistic mass". Einstein rejected this idea however already in 1906/1907 after Planck's less well known paper about the special relativistic mechanics. A nice historical review can be found here (unfortunately there seems to be no freely accessible preprint):

https://doi.org/10.1119/1.3160671
 
  • #63
Well the funny thing is, I just watched a YouTube video and get it now. Don’t know why i didn’t try it earlier, I think because YouTube is worse for reliability than the internet in general I didn’t trust it. Anyway, I was on the right path with my first question about motion (where I ask if the discrepancy is due to the moving observer not aware he is moving -post 3), but Was told I was wrong so abandoned it. I know that IS wrong btw, but if you look carefully and see the context my point is you should be able to see where I was going with it, and I was close the “getting it”. Ever since then I’ve been on a wild Goose chase and i was never going to figure it out as after I was looking in the wrong area.
 

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