The Voyager spacecraft have been in the news lately, because their thirty-year journey has now taken them to something very like the edge of the Solar System. Of course, that’s something of an arbitrary boundary. It’s partly a matter of human-centered definition; and it has varied, too, because the Voyagers keep making new discoveries.Voyager 1 is beaming back data about the solar wind; it has reached a strange place, the “heliosheath,” a sort of solar bubble, described by Ed Stone, the chief project scientist, as “a sluggish, turbulent ring.”
Stone and I were on Science Friday last week with Ira Flatow. Stone explained that the fairly weak transmitter on board, at its current distance of 11 billion miles, still manages to send information earthbound at a rate of 160 bits per second, which reminded Ira of his ancient 300-baud modem.
It happens that Voyager makes a cameo appearance in The Information. That’s not because of any of its scientific discoveries but because it is carrying an outbound message—information from us (earthlings) to any faraway creatures who should chance to encounter this contraption in years to come.
The information is stored in what is called the “Golden Record.” It is a 12-inch disk, a phonograph record, not vinyl but gold-plated copper. (The record can be seen affixed to the spacecraft in the photo above.) A committee led by Carl Sagan chose sounds of the earth: greetings in fifty-five languages, the voices of whales and crickets, the tapping of a telegraph operator, and music of the West and East including the first prelude of Bach’s Well-Tempered Clavier as played by Glenn Gould.
It is worth remembering that as of 1977, the phonograph was the most popular technology in existence for the preservation of sound.
The question arises—and this is why I discuss it in The Information—assuming the alien spacefarers manage to play the disk, how much will they understand? What sort of implicit knowledge is required—what sort of shared code book? One would like to think that the Bach prelude, if not the chatter of crickets, will convey some meaning.