When NASA sent out its Voyager spacecraft, it included a record on each probe as an example of life on Earth.
Made of gold-plated copper, the record was designed in 1977 by a committee chaired by Carl Sagan. In addition to 115 images and a variety of nature sounds, the record includes greetings in 55 languages and dialects as well as selections of music.
The record’s cover is electroplated uranium-238, which can be used to date its age. In the upper-left corner are drawings of a record, with binary arithmetic to indicate how it is played. The bottom-left image is a map, showing the frequency and location of the Sun’s pulsars. The waves of picture signals are illustrated in the upper-right corner, with a final image replicating the first image on the record. The bottom-right image is of the lowest states of the hydrogen atom, indicating the time interval.
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