Subject: Re: OT: what does an expanding universe mean?
In macroscopic relativity, [photon] propagation doesn’t experience time dilation, which means they exist simultaneously at their points of emission and absorption.

That's correct. Relativity attributes no passage of time to anything traveling at the speed of light. That's the basis of communication — allowing an accurate reception of source emission at object absorption, regardless of separation. It's how we come to know our environment ... the very definition of quantum entanglement.

Tom