What is the Voyager Golden Record?

NASA launched Voyager 1 and Voyager 2 in 1977, and each carries a 12-inch gold-plated copper phonograph record. A committee chaired by astronomer Carl Sagan chose the contents: 115 images, natural sounds such as surf, wind and birdsong, spoken greetings in 55 languages, and about 90 minutes of music from many cultures. The cover is engraved with instructions showing how to play the record and a map locating the Sun using pulsars. A small sample of uranium-238 on the cover can act as a clock, letting finders work out how long ago it was made. Both spacecraft are now in interstellar space.