In The Lives of a Cell: Notes of a Biology Watcher, Lewis Thomas suggests that we only broadcast music, because it’s the only thing we’ll still be proud of hundreds of years from now when they actually receive our signals. He suggests Bach. S’pretty diminishing to think about how nothing that is being done during my lifetime (by myself or others) is worth sharing, while Bach composed over 1000 pieces of music, many of them masterpieces that stand the ultimate test of time (worth alien attention apparently). He also had time to father 20 children.