Can a Photon Exist in Multiple Places Due to the Problem of Simultaneity?

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Discussion Overview

The discussion centers around the concept of whether a photon can exist in multiple places simultaneously, particularly in the context of the problem of simultaneity in relativity. Participants explore the implications of different reference frames and the nature of light's speed.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants suggest that if every observer measures the speed of light as constant, it might imply a photon could be in multiple locations simultaneously.
  • Others argue against this notion, stating that a photon cannot occupy more than one position at a time, emphasizing the importance of reference frames.
  • One participant proposes that if a photon is emitted from a moving source, observers in different frames may calculate different positions for the photon based on their relative motion.
  • Another participant clarifies that while observers may measure different distances to the photon, it still occupies a single position, with differences arising from the coordinates used in their respective frames.
  • Some participants express confusion about simultaneity and how it affects measurements of a photon's position, indicating that time is experienced differently in various reference frames.
  • A later reply introduces the idea of cosmic time and position, questioning whether there exists a universal perspective in relativity.

Areas of Agreement / Disagreement

Participants generally disagree on the interpretation of a photon's position across different reference frames, with some asserting that the photon has a single position while others suggest that measurements can yield different positions. The discussion remains unresolved regarding the implications of simultaneity and cosmic perspectives.

Contextual Notes

Participants express varying levels of understanding regarding the implications of relativity, simultaneity, and the nature of light's speed. There are references to the Heisenberg Uncertainty Principle and the complexities of measuring a photon's position, which may not be fully addressed in the discussion.

keepitmoving
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i don`t mean to be beating a dead horse but if every observer measures the speed of light to be C, doesn`t that make for the possibility of a given photon being in more than one place at once? I realize there can be a problem of sumultaneity which i don`t understand.
 
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How are you getting the conclusion that a photon could be in more than one place at once? It can't, but I'm not sure how best to explain why unless you present your reasoning.
 


I think what the OP is trying to say is if you're a photon going at the speed of light then light will travel away from you at the speed of light and so maybe the photon will travel faster than c?

Anyways, this isn't true due to relativity. If you're in the photon's reference, light will travel away from you at c. However, if you are an observer, you'll just see the photon going at c. The photon isn't in multiple places, it's just dependent on reference.
 


keepitmoving said:
photon being in more than one place at once? I realize there can be a problem of simultaneity which i don`t understand.
There is no absolute "at once" for all observers. Simultaneity is relative. I guess that is your problem, but you have to describe your reasoning more accurately.
 


bucher said:
in the photon's reference
This concept doesn't really make sense. See my posts in this thread for an explanation.

I think you're right about what the OP is thinking.
 


i know i`m on the simple side but here goes - if a moving emitter sends a photon out and the photon moves at c away from the moving emitter such that the photon is always at c x time distance from the moving emitter, then that photon has a position at any instant. If another observer is moving in the opposite direction from the moving emitter and he also measures that same photon, then his c x time from his position to the photon would yield a different position for the photon. They`re both using c as the speed and using the same time so that should yield different positions for the photon. I must be haywire here. Sorry. Your help is appreciated.
 


Well, since the emitter and the observer are going at different speeds relative to each other then they would measure different positions due to the time delay of relativity. If the emitter and the observer waited 1 second, then that one second would be different in either reference frame since they are moving at different speeds relative to one another.

Though this difference may be extremely small, they are using this time to find a position of a photon going at c. If one was to factor in the time delay with respect to the other's movements, then both would measure the same position of the photon.

I should note that this is without regard to the application of the Heisenberg Uncertainty Principle and the ability to measure a photon going away from you.
 


keepitmoving said:
i know i`m on the simple side but here goes - if a moving emitter sends a photon out and the photon moves at c away from the moving emitter such that the photon is always at c x time distance from the moving emitter, then that photon has a position at any instant. If another observer is moving in the opposite direction from the moving emitter and he also measures that same photon, then his c x time from his position to the photon would yield a different position for the photon. They`re both using c as the speed and using the same time so that should yield different positions for the photon. I must be haywire here. Sorry. Your help is appreciated.

Measuring the speed of light means measuring speed.
Speed is defined as distance divided by time.
Time is passing at different rates in the two frames of reference experienced by the two moving observers. A second in one frame is longer than a second in the other, thus, the photon is measured as being farther from the emitter.
 


keepitmoving said:
i know i`m on the simple side but here goes - if a moving emitter sends a photon out and the photon moves at c away from the moving emitter such that the photon is always at c x time distance from the moving emitter
That's true in the frame of the emitter, using that frame's distance and time measurements.
, then that photon has a position at any instant.
OK.
If another observer is moving in the opposite direction from the moving emitter and he also measures that same photon, then his c x time from his position to the photon would yield a different position for the photon.
No, the same photon has a single position. What's different are the coordinates of that position. That second observer will measure the photon's distance from him using his own distance and time measurements.
They`re both using c as the speed and using the same time so that should yield different positions for the photon.
No. Same position, just differently described.
 
  • #10


thank you much for your help.
Another question is - how does cosmic time and cosmic position figure in. It seems to me that relativity emphasizes each point of view as being valid but isn`t there a cosmic point of view and time?
 

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