What got me rattling down this track was the problem of timekeeping across astronomical distances. Since reference frame is a critical concept, is it reasonable to have your clock so far away that it
For example, let us posit a pulsar 30,000 light years distant. Let us further posit that its periodicity is slowly lengthening, by a degree both measurable and predictable. Say that I know from a certain zero point, say, Earth on a given day and time, what the periodicity is. Then, some arbitrary amount of time later, having moved at relativistic or supraluminal speeds to an astronomical distance, I measure my beacon star's periodicity again. I then calculate backwards (or, potentially forwards) from my known zero point reference.
Have I in my new, arbitrary location now established the time at my zero point? Ie, have I synchronized my clocks?
I am absolutely certain there is at least one serious error here, but I can't see it yet. I'd appreciate comments that might correct this idea, or references to more successful examples of this kind of thinking.
