>>14409489if entanglement shenanigans + teleportation (i.e. 3D printing) become viable, then all you'd have to do is lay an initial "landline" from earth to a receiver, an entanglement receiver if you will, to any distant body. Once you know the coordinates or w/e to the line, you can simply dial it in and start instantly sending information.
Any advanced civilization should already know this, so after laying a landline of their own it'd make sense to start broadcasting instructions via light on how to build and connect to their own receivers.
There could be light pulses from a foreign galaxy RIGHT NOW, telling us how to connect with foreign advanced civilizations.
