Photons live in a singularity?

[wjmt88]

Photons "live" in a singularity?

I did some searches, but couldn't find an answer to this on this forum.

Since a photon can travel 1 km, 1 lightyear, 1 million lightyears in ZERO time from its own perspective, and if we did a though experiment from the point of view of a photon, does that mean that current knowledge says that from the point of view of a photon, the entire universe is a singularity?

Thanks!

 

[dx]

In the current framework of physics, 'point of view of a photon' has no definite meaning.

 

[Rasalhague]

I did some searches, but couldn't find an answer to this on this forum.

It's come up three other times this month:

Stationary photons, Oct20 (page 1).
Photons and time, Oct14 (page 2).
Irrelvancy of motion in C perspective, Oct6 (page 4).

Here is a detailed answer from Fredrik:
https://www.physicsforums.com/showthread.php?p=2205554#post2205554

 

[ghwellsjr]

I did some searches, but couldn't find an answer to this on this forum.

Since a photon can travel 1 km, 1 lightyear, 1 million lightyears in ZERO time from its own perspective, and if we did a though experiment from the point of view of a photon, does that mean that current knowledge says that from the point of view of a photon, the entire universe is a singularity?

Thanks!

Usually when people say "from the point of view of a photon", they mean "in the reference frame of a photon". But photons cannot be in a frame of reference because when we talk about an observer or an object or anything having a frame a reference or being in a frame of reference, we mean the frame in which that thing is at rest. SR states, in effect, that the speed of a photon is c in any frame of reference. Photons cannot both be at rest and be traveling at c at the same time in the same frame. It's pointless to even think about what would be happening in such a situation.

So the reason you cannot find an answer is because the question doesn't make sense.

 

[jshrager]

Maybe photons don't exist at all -- all we're detecting when we say we've detected a photon is two points in space-time touching one another.

 

[member 11137]

I did some searches, but couldn't find an answer to this on this forum.

Since a photon can travel 1 km, 1 lightyear, 1 million lightyears in ZERO time from its own perspective, and if we did a though experiment from the point of view of a photon, does that mean that current knowledge says that from the point of view of a photon, the entire universe is a singularity?

Thanks!

I ignore if the entire universe is a singularity but I know that discontinuities can propagate along bicharacteristics. At the same time I know that photons also propagate along bicharacteristics. Does it induce that photons are discontinuities?

Just remember : A -> B and C -> B does not imply A = C !

So, the question stays open.

 

[1MileCrash]

Here's my follow up question-

From the "reference" of a photon, pretend we hitched a ride with one. We are traveling at C from the sun to the earth. We experience this journey as instant, and from our reference time has stopped for other references, they are at a standstill.

Yet when we reach earth, it has rotated 2 degrees. (8 minutes journey from Earth reference, 2 degree rotation)

How can Earth rotate 2 degrees during our journey if time for Earth is at a standstill from our reference?

 

[ghwellsjr]

Did you read my answer in post #4 to the original question in post #1?

Usually when people say "from the point of view of a photon", they mean "in the reference frame of a photon". But photons cannot be in a frame of reference because when we talk about an observer or an object or anything having a frame a reference or being in a frame of reference, we mean the frame in which that thing is at rest. SR states, in effect, that the speed of a photon is c in any frame of reference. Photons cannot both be at rest and be traveling at c at the same time in the same frame. It's pointless to even think about what would be happening in such a situation.

So the reason you cannot find an answer is because the question doesn't make sense.

I thought I made a very-simple-to-understand-reason why a photon does not have a reference. Why do you then ask this question that doesn't make sense? I would really like to know why you didn't understand my answer. Please help me understand why you don't understand the meaninglessness of your question.

 

[1MileCrash]

Did you read my answer in post #4 to the original question in post #1?



I thought I made a very-simple-to-understand-reason why a photon does not have a reference. Why do you then ask this question that doesn't make sense? I would really like to know why you didn't understand my answer. Please help me understand why you don't understand the meaninglessness of your question.

Im sorry, your response was very thoughtfully written out and easy to understand. I thought my intent was clear.

My follow up question to the op was a demonstration of essentially, your point. Yes, the question doesn't make sense and the paradoxical conclusion does not make sense because assigning a reference to a photon does not make sense. That was the point, and why i initially quoted "reference" when referring to the photon.

I was agreeing with you.

 

[ghwellsjr]

OK, thanks for explaining.

 

[Trenton]

The phrase 'point of view of a photon' is meaningless for reasons well explained above and so the question 'does a photon live in a singularity?' is likewise menaingless.

But to be contrarian, the question 'is a photon a singularity?' may have merit. After much contemplation of what the geometry of a photon might be I remain clueless but I have heard and read claims that a photon can be thought of as a 2D rotating disk traveling along the perpendicular axis. A singularity is so called when one or more divisors become zero.

A 2D photon if such a model is valid, has no volume and given it has mass by virtue of it's energy, would be infinitely dense! My instinct tells me this is wrong but the question is in what way?

 

[Vanadium 50]

This thread is three years old.