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In a recent thread discussing the age of photons it is mentioned that from the photon's perspective, the universe is two-dimensioned. I take it that these two dimensions are both perpendicular to the direction of travel, as the photon travels at the speed of light and thus is everywhere on its path at once.

However, if I'm not mistaken, a photon can change direction. Thus, the 2-D plane perpendicular to the direction of the photon also changes. How is this fact perceived by the photon?

Of course I am aware that a photon has neither sentience nor time, so what does this perception even mean for a photon? If it has no meaning, then what is the meaning of 2-D space for the photon, seeing how it can never interact with, be affected by, affect, or travel to any other location on that 2-D plane?

dotancohen
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    One view of scattering/reflection is absorption of a photon and re-emission of a new photon. Then you don't have to think of what the photon "experiences". But anyway, it doesn't have a rest frame, so its point of view doesn't have any meaning. – Ruslan Feb 25 '20 at 15:39
  • @Ruslan Surely a photon is not destroyed, and a new photon created, in the process. At some point the original photon will be reemitted, no? Is the reasonable that that original photon will only be reemitted in instances where the direction of travel is exactly the original direction on which the original photon was travelling? – dotancohen Feb 25 '20 at 15:42
  • Downvoter: I would appreciate knowing how I can better formulate the question. I've found no relevant information by searching with DDG, and the question is a direct consequence of another answer by a very highly respected user, so I assume that the basis is sound. – dotancohen Feb 25 '20 at 15:44
  • It's not useful to ask whether a photon is "original" or "different": they are all identical, i.e. in principle indistinguishable. You may of course think that a photon is "original" if it has all the same set of quantum numbers as the one that was previously absorbed, but I don't know whether this would give any useful result. – Ruslan Feb 25 '20 at 15:49
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    Related: How does a photon experience space and time? – Ruslan Feb 25 '20 at 15:53
  • Thank you Ruslan, the answers to that question are very relevant to this question. So much so, in fact, that I have no objection to closing this as a dupe. Hopefully the different perspective in this question's title will help future searchers to find that answer. – dotancohen Feb 25 '20 at 15:58

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