Attached to the Voyager probes are the golden records, which are essentially messages-in-a-bottle sent out into the vast sea of interstellar space, containing, of course, the "message of humanity". Although the primary purposes of these records may have merely been commemorative - and not an actual attempt to come in contact with extraterrestrial life - I think most people have an infinitesimal hope that someday in the far future an extraterrestrial civilization will retrieve these records and "learn of the human species".
Now, suppose another extraterrestrial species has done the same thing, and one of their "Voyager probes" (carrying it's own "golden record") comes travelling straight towards us. For simplicity lets assume that its composition is very similar, if not identical, to our Voyager probes. My question is, if it came near Earth, would we be able to retrieve it? An important qualifying question would be, how close would it need to come for us to even detect it in the first place?
I know this question is quite speculative and loose, but I think it's an interesting thought.