Everyone's like: "This is proof of d'em aliens"

...disregarding what people say about actual aliens running around on earth. I find it funny because it's probably not proof of aliens at all it's probably proof of previous civilization on earth. Why? The advanced species don't communicate this way.

Now those bad guys flying around might require the use of such a transmission amplifier but there's nothing to suggest this contingent is not the last of their race. If you could go anywhere and do anything this is probably the last place you'd want to be. The conclusion is that they can't go anywhere or do anything which hints at the fact that they would have no one to broadcast to and nowhere to broadcast it. Maybe it's one of those "if anyone has survived come here" type beacons but that's probably not something you would plant intra-system if you were an alien using broadcast communication because the gravity or solar output might affect the transmission also such a beacon could be intercepted by your pursuers. ;)