In 1997 we sent a laugh into space. Now we know whose.
The Voyager satellites (there are two) each carry a golden record. The record's grooves contain the sounds of Earth, meant to represent our planet to any intelligent life. It includes whale songs, a jungle, a human heartbeat, thunder, Chuck Berry's Johnny B. Good and laughter. On earthly recordings, that laughter is hard to hear, which led an Atlantic reporter on a quest to learn what it sounded like — and find out who was laughing.
Perhaps unsurprisingly, the laugh (probably) belonged to late astronomer Carl Sagan. Sagan was integral in the record's conception, and while he was working on it he fell in love with the creative director, Ann Druyan. Their daughter, Sasha Sagan, told the Atlantic Druyan included the laugh because it "was the very first impression she ever had of my dad ... she wanted it to live on forever."