Madowanai Hoshi - Vol. 4 Ch. 37 - Color of the Sky

[MangaDex]

 

[DracoInduperator]

I was under the impression that radio waves and such dissolved to unintelligible meaningless jumble of static a few light years out from it's source. So I wonder how Sirius was able to hear the messages, forget the whole space-time compression thing about coming before they were sent.

 

[Glomoro]

If that's usually the case I'd just go ahead and assume it's some sci-fi stuff 'cause these humans were more advanced than we currently are to the point that their post-apocalypse is still more advanced than us in various aspects.