[kburman]

Have a question related to this, if a photon has zero proper time between emission and absorption, how should I think about the influence of later-created photons or fields on it?

In our frame, we can interact with a photon long after it's emitted send it through a filter, bounce it off a mirror, measure it, etc. But from the photon's own “no proper time” perspective, does it make sense to ask how something created after its emission could affect its path?

[mr_mitm]

The photon doesn't have an inertial frame of reference precisely because it's moving at the speed of light, so it doesn't have a perspective. It's a (quantized) wave in the electromagnetic field. The closer you get to the speed of light, the closer the proper time of the journey goes to zero, but actually taking the limit does not make sense physically.

[MaxikCZ]

I wonder if Photon doesnt have an inertial frame of reference - from our point of view.

Like, from our point of view, we assume that from photons point of view it has no perspective.

But maybe we are limited by our spacetime, where photon goes trough our universe in an instant, and continues to pierce infinite universes over its non-zero frame of reference.

[hhjinks]

>does it make sense to ask how something created after its emission could affect its path

The problem here is likely the concept of "after". It's relativity; what's "after" in our frame of reference isn't after in all frames of reference.