I sort of get that light doesn’t age - after all, a clock attached to a photon would never tick. If I think through the whole clock moving relative to an observer, I can see the conclusion it leads to.
I’ve heard it said that therefore all light is the same age as the big bang. I don’t know if that’s glib and oversimplifying the truth, or if it is meaningful to say the photon is as old as the big bang.
From the photon’s point of view, what does it mean to not age? A photon from our point of view is created, say, by an electron in a hydrogen atom in the sun, and 8 minutes later, it hits some pavement and gets absorbed and transforms into heat. It existed for 8 minutes. It did not exist yesterday, and it does not exist now.
Does the photon experience that? Did it exist for the entire 93 million mile path all at the same time? Did it experience existence as a 93 million long line, rather than as a quasi-particle moving from the sun to the earth? Does it just sort of ‘exist’ in that slice of the spacetime loaf, as something that neither moves forward nor backward through time? Is there any intuitive way of understanding a photon’s life experience?