See zone of avoidance. At 7b ly, alien civilization would take up 4 degrees in the sky, and it seems that Milk Way makes more than that hard to see (not impossible though).
It seems that there are definitely some extragalactic objects known in the zone of avoidance, however I haven’t been able to find how far the farthest of them are, or how close to the center they appear. Radio waves pass through dust more easily than visible light, but I don’t think they are entirely unhindered. I have no idea, you might want to ask these questions somewhere like physics.stackexchange, where somebody knows something.
See zone of avoidance. At 7b ly, alien civilization would take up 4 degrees in the sky, and it seems that Milk Way makes more than that hard to see (not impossible though).
My impression from wikipedia is that radio transmission is still fine, so radio loud quasars are still easy to detect. Does that sound right?
It seems that there are definitely some extragalactic objects known in the zone of avoidance, however I haven’t been able to find how far the farthest of them are, or how close to the center they appear. Radio waves pass through dust more easily than visible light, but I don’t think they are entirely unhindered. I have no idea, you might want to ask these questions somewhere like physics.stackexchange, where somebody knows something.