If you go to Earth and head straight to the forgotten shore, there will be 2 destroyed ship wrecks (Boats) Jump to the top, kill the enemies that are around you and listen to the radio on top of the ships, they speak in a different language, possibly spoken backwards I don't know... This goes on a repeat, it gets hard to listen to as some bits fade out but keep a good listhen out for them guardians, who knows what is still hidden is our planets?