"The 'Voyager Golden Records' are identical 12" LPs mounted on and launched with the 'Voyager' exploratory spacecrafts in 1977. The records contain sounds and encoded images showing the diverse cultures and life of Earth, and were created as time capsules of humanity should any intelligent extraterrestrials encounter them. A stylus and instructions written in binary (for playback and image decoding) were also included. The LPs run 90 minutes, are constructed of gold-plated copper, and housed in aluminum covers electroplated with ultra-pure uranium-238, which has a half-life of 4.5 billion years. A civilization that encounters them will be able to use mass spectrometry to determine the ratio of remaining uranium, thus revealing the record's ages. Eight copies were pressed, two are on the Voyager spacecrafts, one is on display at the Smithsonian, with the remainder archived at Jet Propulsion Laboratory in southern California. Although neither spacecraft is heading toward any particular star, Voyager 1 will pass near the constellation 'Camelopardalis' in about 40,000 years. Currently, both Voyager 1 and 2 are in interstellar space, but still within the bounds of the Oort Cloud."
