In describing what the Voyager captured in that grainy photograph of mostly empty space, Sagan limned Earth as a “pale blue dot.” That became the moniker of the photograph itself and the title of his bestselling book published later that year, in which he wrote that “everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives” on this “mote of dust suspended in a sunbeam.”