A photon is, from its point of reference, at the point of creation and at the point of destination at the same "time". Its literally seeing both parts of the universe at the same time, and since its traveled some distance over that time it cannot perceive, its essentially connecting 2 points in spacetime.
If I understand it correctly, every photon exists, from its point of view, for only infinitely small amount of time (similar to how virtual particles do exist from our point of reference), but for us its so easy to "play" with the photon along its path, giving us plenty of time to even decide what we want to do with it after it has already been created.
Its just so bonkers that time can be perceived such differently depending on frame of reference.
Lately, I've been wondering what evidence we have that the speed of the photon/light is really the universal speed limit, and not a very close fraction of it. I could find the argument that a photon must be massless, otherwise photons of different wavelengths would travel at different speeds. But that says nothing of the speed of a massless photon relative to maximum causality propagation speeds.
My question is if this part of the model has been validated experimentally somehow.
BTW, it seems odd calling a photon a zero-energy object.
> every photon exists, from its point of view, for only infinitely small amount of time
Why is that amount “infinitely small” and not 0 since photons travel exactly at the speed of light?
In the mathematics of infinity, something can have exactly zero probability yet still happen, and exactly one probability yet nonetheless fail to happen (hence the standard term “almost surely”).
If something can have literally zero probability of existing yet still exist, why can’t it exist for literally zero time yet still exist?
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?
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.
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.
Are we saying then that it is theoretically possible that (a) photons have a zero or near-zero lifetime, but that also (in our frame of reference) (b) they exist for a finite duration of time and are visible during that time simply because time stops for them ? Or did someone manage to slow down light to some fraction of light speed ?
If one twin stays on earth and the other makes an intergalactic trip (with the speed of light), upon return, the one on earth will have aged much more than the one on the trip.
(p.s. the spacefaring twin doesn't have to move at the speed of light, and indeed cannot, it's enough to move at a "relativistic" speed, i.e. fast enough that this is actually measurable. With today's clock that doesn't have to be very fast actually)