Cosmic Debris

When NASA sent the Voyager into space 30 years ago, it contained record albums intended for alien consumption.
In the mid-1970s, when the Voyager spacecraft were being completed, pop cosmologist Carl Sagan convinced NASA to include a message from Earth on the probes. They were to bring news of us to alien beings in the unknowable reaches of the galaxy and beyond.
Sagan decided that the delivery mechanism for this message should be a golden record, packaged with a cartridge and needle, as well as abstract mathematical instructions for how fast to spin the disc and at what frequencies it would emit sound. You can listen to the entire recording HERE