Implying whatever happened so many thousand years ago will have an impact here at about the same time we observe it happening from here? (I.e. light coming from that time and direction arrives here at about the same time as whatever implication this has to us does.)
If so, what kinds of implications would this have to us? Is this quasar radiation merely an observable thing, or could it disturb communications or something along those lines?
I think that’s the implication, but it goes even further than you say: because of the relativity of simultaneity (see Wikipedia), there is no absolute yardstick of the timeline.
In other words, “it happened n years ago”, like “it’s happening right now”, isn’t defined by itself; it only makes sense for given values of here and there.
This comes out of special relativity and is closely connected with the fact that nothing, not even photons, can move faster than a certain speed.
It's interesting — this both appeals to my intuition and is hard for me to completely wrap my head around... I can see it but I realise that I don't naturally think like that.
Essentially, it's meaningless to say that two things are absolutely happening at the same time in different places. There is no such thing as "meanwhile, somewhere else". Or at best, it's a very limited model.
When we observe the light from an event is when it actually happens, from our perspective, for all intents and purposes. Kinda screws up our whole way of thinking, but this is how the universe actually works.
