Before there was Voyager, there were Pioneers 10 and 11. Both spacecrafts carried small metal plaques that displayed time and origin in case the ships were boarded by any intergalactic neighbors, according to the Jet Propulsion Laboratory at the California Institute of Technology.
Voyager 1 and 2 carry more go-getting time capsules to help extraterrestrials understand us and our story. Each unmanned craft carries a Golden Record, which is a 12-inch gold-plated copper phonograph disk that holds sights and sounds from Earth. A gold record of our greatest hits, if you will.
A committee headed by Carl Sagan, an American astronomer from Cornell University, put together the content of the disk. Natural sounds like thunder, wind, birds and other animal noises were recorded along with 115 images. Music from a variety of eras, greetings in 55 languages (from Akkadian which was spoken 6,000 years ago to a modern Chinese dialect) and printed messages from President Carter and U.N. Secretary General Waldheim were assembled by Sagan and his team.
This could be an American Phaistos Disk for another life form who stumbles upon it. The records are each packed away in an aluminum jacket with a cartridge, needle and instructions in a symbolic language.
Only about 40,000 years to go and Voyager 1 and 2 could potentially approach another planetary system.
"The spacecraft will be encountered and the record played only if there are advanced spacefaring civilizations in interstellar space," said Sagan. "But the launching of this bottle into the cosmic ocean says something very hopeful about life on this planet."
The book "Murmurs of Earth" tells the story of how the Golden Records came to be. "Murmurs of Earth" was originally published in 1978 and was reissued in 1992 (with a CD-ROM replica of the Voyager disk). The book is out of print at this time.
The information for this article was obtained from the Jet Propulsion Laboratory at the California Institute of Technology's website.
