NASA thought about it and placed two, one on Voyager I and Voyager II
launched back in 1977:
"Voyager 1 and 2 both carry with them a golden record that contains
pictures and sounds of Earth, along with symbolic directions for
playing the record and data detailing the location of Earth. The
record is intended as a combination time capsule and interstellar
message to any civilization, alien or far-future human, that recovers
either of the Voyager craft. The contents of this record were selected
by a committee chaired by Carl Sagan."
Wikipedia entry: Voyager program