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# A Photon's perspective?

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Everything I've found so far in my Internet search for the question "What does the universe look like from the perspective of a photon?" has led to the following answer:

A photon experiences zero time and zero distance. Essentially, it exists for only an instant (from it's own perspective), no matter how far it travels (from an outside perspective). This seems to exactly coincide with what Special Relativity says about an object moving at such relativistic speeds.

However, it has recently come to my attention in another thread (another thread ) that because a photon has no mass, the effects of Special Relativity do not apply:

Mass and Energy can be viewed as equivilant not equal. That and one cannot selectively apply lorentz transforms (ie time and not space or vice versa). The theory of SR applies only to inertial[/i'] reference frames, as in those that contain mass.

So it seems that it is not true to say that a photon experiences zero time... which brings me to my question:

What does the universe look like from the perspective of a photon?

(with respect to time, distance, etc.)

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You mean, like if we just where a photon and traveling?

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The effects of special relativty do apply as indeed they apply to everything (the Lorentz invaraince is beleived to be a fundmanatal property of nature within it's limits).

BUT in special relativty a frame of reference cannot be defined for a photon. One of looking at is that any MCIF (a momentarily co-moving refrenc frame i.e. the frame in which a partcile considers itself to be at rest at any 'instant' of time, this is a generalization of an inertial frame as it allows us to consider the frames of objects that are accelartng too) has the property, by defintion, that the particle considered is at rest, yet it is a postulate of special relativty that the velcoity of a photon is c in all MCIFs so it CANNOT be at rest in any MCIF and therefore cannot have a rest frame.

Therefore it is meaningless in special relativity to talk about the 'photon's perspective'.

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Therefore it is meaningless in special relativity to talk about the 'photon's perspective'.

Is there any realm of science where the question might not be 'meaningless' ?

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Is there any realm of science where the question might not be 'meaningless' ?

Not really, relativty must be taken into account.

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I would even go a step futher and restate what I already did. I believe massless particles do not obey special relativity. I might be wrong as this is more of a hunch than a confirmed scientific principle but it would eliminate the need to talk about such frames. How can an object see the whole universe collapsed to a point and have time stop for it if outside observers clearly see it traversing from one region to another. Its beyond contradiction, its impossible.

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I would even go a step futher and restate what I already did. I believe massless particles do not obey special relativity. I might be wrong as this is more of a hunch than a confirmed scientific principle but it would eliminate the need to talk about such frames. How can an object see the whole universe collapsed to a point and have time stop for it if outside observers clearly see it traversing from one region to another. Its beyond contradiction, its impossible.

Massless particles do obey special relatvity, but they also produce some reuslts that may be counterintutive. For exmaple the 4-velpcity is not defiend for a massless particle and they also give rise to null vectors (a null vector is not necessarily a zero vector in SR; a null vector is a vector whose square norm is zero and a zero vector is a vector whose components are all zero), which by the defintion of orthogonality are orthogonal to themselves (of course zero vectors which are the only kind of null vectors in basic 3-vector algebra can also be considered to be orthogonal to themselves anyway)! But none of these are actually problems becasue photons don't have rest frames.

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The effects of special relativty do apply as indeed they apply to everything (the Lorentz invaraince is beleived to be a fundmanatal property of nature within it's limits).

BUT in special relativty a frame of reference cannot be defined for a photon.

Therefore it is meaningless in special relativity to talk about the 'photon's perspective'.

I can only interpret this as meaning that time does not exist for the photon. This would satisfy all three of the above quotes, as well as answer my question.

If the photon experiences zero time, it obviously adheres to the effects of SR.

If the photon experiences zero time, a frame of reference cannot be defined.

If the photon experiences zero time, it would have no time to have a 'perspective'. Therefore, I suppose, you could say that particular phrasing of the question would 'technically' be meaningless.

Am I correct? and if not, would it help to rephrase the question like so:

Does time pass for a photon?

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The question becomes menaingless in SR, as you cannot define reference frame for the photon so you cannot talk about whetehr or not time passes for a photon. The problem is that peole use theb formula for time dialation and input the value 'c' and think the answer is meaningful as it tells you nothing about the photon's reference frame.

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The question becomes menaingless in SR, as you cannot define reference frame for the photon so you cannot talk about whetehr or not time passes for a photon. The problem is that peole use theb formula for time dialation and input the value 'c' and think the answer is meaningful as it tells you nothing about the photon's reference frame.

When you say 'it tells you nothing about the photon's reference frame.' it sounds, to me, like you are simply saying that we don't have enough information to answer the question at hand, or... special relativity cannot tell us whether or not time passes for a photon.

There IS an answer to the question... it is a very simple question. We just don't know the answer, and the answer cannot be found using SR. (This is what I assume you mean but do not say)

This is very different from the question being 'meaningless'. Of course, you always word it like so: "The question becomes meaningless in SR..."

you cannot define reference frame for the photon so you cannot talk about whetehr or not time passes for a photon.

Sure I can!... Isn't that what we're doing?

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I hope I am not sounding arrogant or trying your patience Aeschylus. I do not mean to, and I most definitely appreciate your replies, as well as respect the input you give, as it obviously comes from a mind more schooled than my own. I am only trying to understand what it is that you're trying to say.

I have a hard time accepting an answer that says my question is meaningless. What does that mean? There is no answer? The answer is unattainable via our current understanding of the universe? The answer is unattainable. period.?

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What I mean is that it's like talking about 'north' of the North pole, by the way we define the north and the North pole there is nothing north of the North pole, simlairly by the way we define reference frames and photons, photons don't have reference frames. It's not a gap in our knowledge, it's just that our knowledge tells us that such questions are meaningless.

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Does time pass for a photon?

I'm just a layman, but...... time as I know it is the thermodynamic arrow of time, it is the increase of entropy, in order for there to be time for a photon it would need to be:

1: conscious

2: able to observe the effects of increasing entropy

So even though this is nothing to do with space-"time" and relativity, it also shows that time doesn't exist for a photon.

Edit: actually gives me a good idea for a thread.

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