Question from the FAQ on Rest Frame of a Photon

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    Frame Photon Rest
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Discussion Overview

The discussion centers on the concept of the rest frame of a photon, particularly in relation to the implications of statements made in DH's FAQ article. Participants explore the meaning of time and length at the speed of light, the validity of the term "light year," and the existence of a rest frame for photons.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants suggest that if light travels at speed c, then concepts like "light year" and "speed of light" become meaningless, as time and distance shrink to zero at that speed.
  • Others argue that the idea of an "inertial rest frame of a photon" is self-contradictory, as "inertial" implies a constant speed while "rest" implies zero speed, thus asserting that such a frame does not exist.
  • One participant posits that while one can assume a rest frame for a photon, doing so leads to contradictions with established principles like Maxwell's Equations.
  • Another participant questions the necessity of a frame for the principles discussed in DH's article to apply, seeking clarification on the implications of the article's statements.
  • There are discussions about the interpretation of terminology and the authority of the FAQ article, with some participants feeling that the terminology used is not their own and should not be attributed to them.

Areas of Agreement / Disagreement

Participants express differing views on the existence and implications of a rest frame for photons. There is no consensus on the validity of the concepts discussed, and the conversation remains unresolved regarding the meaning and implications of the statements made in DH's article.

Contextual Notes

Participants highlight the limitations of discussing the rest frame of a photon, noting that while certain characteristics of time and length are described as approaching zero, they never actually reach that state. This introduces ambiguity in the discussion of the implications of such concepts.

  • #61
ghwellsjr said:
Since it will take ten minutes for the image of B to reach A and another ten minutes for the laser pulse to travel from A to the intersection, A needs to pull the trigger twenty minutes before it appears that B would arrive at the intersection, in other words when B is 33.333 miles before the intersection.

Thanks ghwellsjr.

So as Harold pointed out here:
harrylin said:
In order to understand it, stick with nearly the speed of light as I suggested, and reflect on that. After you understand what goes on for that case, then you can extrapolate to the unattainable limit for a clock with v=c, as Einstein did.

Harald

I though I would try and do just that.

Imagine that instead of A firing a laser, A just decides to set off in his super fast ship and fires himself at B.

So ignoring acceleration for now, if A was capable of traveling at 0.9999986111095911 c, then A would feel that he covered the 10 light minutes in just 1 second.

A must also see B travel the 33.3333 miles B was away from the intersection in just one second too, as A will still hit B, but will just be a little off target.

However B would still feel like it took him 10 minutes.

So if we imagine just for a moment what a photon might experience from A's laser in the original experiment, once the photon was created, it would be instantaneously at B's target where it would be absorbed.

B, which was 33.333 miles from the intersection would also have to be instantaneously at the intersection for the photon to hit the target.

Although A and B still feel the passing of time as normal, for the photon, as everything happens instantaneously, there is nothing for the photon to experience. Which I guess is why we can't look at this problem from the frame of a photon. There is nothing to look at!


I know that the above is not strictly in keeping with the principles of SR, but I thought it might help address DrDon's questions.
 

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