Hmm...just a random thought that just popped in my head, with the thoughts that 5c might be artificial, and the possibility of the Missing being involved: What if 5c is actually a Thargoid Mothership that's gone dormant, the barnacles are actually Thargoid combat ships growing on its surface, and the probes & artefacts are actually something created by one of the Missing colony ships after they passed through and interacted with a Thargoid diplomatic and/or combat unit? It would make some sense...the UAs all point at Merope in a 150ly bubble, almost like an early warning net. The UPs all point at 5c, which may be the threat the UAs are guarding. The sound picture is being referred to as a Key...so, is the map in that picture pointing at a particular location on 5c that, when you arrive and honk a UP, will cause something to open up or some event to trigger? As for the Missing...if we could just figure out where the UAs and UPs were broadcasting TO, maybe we'd find a Generation Ship out there, possibly melded with Thargoid tech, maybe even a mixed Tharg/Human society. Or is the location on 5c I'm postulating actually a crashed Generation Ship, or even a hangar that a Generation Ship was pulled into....*tinfoil intensifies*