Voyager 1 (launched September 5, 1977) and Voyager 2 (launched August 20, 1977) were unmanned space probes designed to explore the outer planets and then travel out of the solar system. A gold-coated copper phonograph record containing a message to any possible extraterrestrial civilization that they might encounter is attached to each spacecraft. The record contains both video and audio images of Earth and the civilization that sent this message to the stars.

The record begins with 118 pictures. These show Earth’s position in the galaxy; a key to the mathematical notation used in other pictures; the sun; other planets in the solar system; human anatomy and reproduction; various types of terrain (seashore, desert, mountains); examples of vegetation and animal life; people of both sexes and of all ages and ethnic types engaged in a number of activities; structures (from grass huts to the Taj Mahal to the Sydney Opera House) showing diverse architectural styles; and means of transportation, including roads, bridges, cars, planes, and space vehicles.

The pictures are followed by greetings from Jimmy Carter, who was then president of the United States, and Kurt Waldheim, then secretary general of the United Nations. Brief messages in 54 languages, ranging from ancient Sumerian to English, are included, as is a “song” of the humpback whale.

The next section is a series of sounds common to Earth. These include thunder, rain, wind, fire, barking dogs, footsteps, laughter, human speech, the cry of an infant, and the sounds of a human heartbeat and human brainwaves.

The record concludes with approximately 90 minutes of music: “Earth’s Greatest Hits.” These musical selections were drawn from a broad spectrum of cultures and include such diverse pieces as a Pygmy girl’s initiation song; bagpipe music from Azerbaijan; the Fifth Symphony, First Movement by Ludwig von Beethoven; and “Johnny B. Goode” by Chuck Berry.

It will be tens, or even hundreds of thousands of years before either Voyager comes close to another star, and perhaps the message will never be heard; but it is a sign of humanity’s hope to encounter life elsewhere in the universe.