Earth has been getting radio signals we can't explain since 2007. Experts call them Fast Radio Bursts (FRBs), and all we know is that they're coming from outside the Milky Way.
I've gotten some of these myself. I'm not at liberty to share them right now, but I can share this example. It's pretty similar, except for certain differences that... well, again, classified!Anyway. Take a listen. This signal came from 3 billion light-years away!