In 1977 the United States launched the Voyager I and II spacecraft on a mission to explore the outer Solar System. Both probes returned photographs of unprecedented clarity from Jupiter, Saturn and their satellites, and Voyager II continued its mission at Uranus in 1986 and Neptune in 1989, still functioning 12 years after its launch.
Neither spacecraft will ever return to Earth, but instead they will continue to drift through space for millions of years. On the off chance that they are ever intercepted, however, both spacecraft bear a gold-coated phonographic record with musical selections, encoded pictures from Earth, and greetings from around the world. The following two messages, one recorded, the other written, were included on the record, along with diagrammatic instructions for playing and decoding them.
FROM KURT WALDHEIM:
AS THE SECRETARY GENERAL OF THE UNITED Nations, an organization of 147 member states who represent almost all of the human inhabitants of the planet Earth, I send greetings on behalf of the people of our planet. We step out of our Solar System into the universe seeking only peace and friendship, to teach if we are called upon, to be taught if we are fortunate. We know full well that our planet and all its inhabitants are but a small part of the immense universe that surrounds us and it is with humility and hope that we take this step.
The Earth & Moon photographed together in space, NASA.
THE WHITE HOUSE, JUNE 16, 1977
THIS VOYAGER SPACECRAFT was constructed by the United States of America. We are a community of 240 million human beings among the more than 4 billion who inhabit the planet Earth. We human beings are still divided into nation states, but these states are rapidly becoming a single global civilization.
We cast this message into the cosmos. It is likely to survive a billion years into our future, when our civilization is profoundly altered and the surface of the Earth may be vastly changed. Of the 200 million stars in the Milky Way galaxy, some-- perhaps many-- may have inhabited planets and spacefaring civilizations. If one such civilization intercepts Voyager and can understand these recorded contents, here is our message:
This is a present from a small distant world, a token of our sounds, our science, our images, our music, our thoughts and our feelings. We are attempting to survive our time so we may live into yours. We hope someday, having solved the problems we face, to join a community of galactic civilizations. This record represents our hope and our determination, and our good will in a vast and awesome universe.
President of the United States of America
The complete story of the Voyager interstellar record is told in the book Murmurs of Earth, by Carl Sagan et al., 1978.