Good afternoon all, A few days ago, I had been reading a book on general relativity and cosmology by Dr. Brian Greene, in which something was written that I found to be very profound. (At least, from the standpoint of my own ignorance on the subject.) I was wondering if any professionals could point me in the right direction to learning more about this quandary. In the book, Dr. Greene went on to describe how classical objects, like us, experience the vast enormity of spatial extent in the heavens, yet photons do not. More specifically, it was mentioned that the distance between objects from a photons perspective is zero. This utterly blows my mind. How is this even possible? Is there some kind of underlying prevailing wisdom I'm unaware of wherein distances are just an artifact of spacetime experienced by classical objects? Forgive my speculation, but I'm completely unaware of how to reconcile this statement.