Voyager’s Golden Record was designed as more than a playlist. Each 1977 spacecraft carries a 12-inch gold-plated copper disc, and the aluminium cover is part of the message: its engravings explain how to play the record, reconstruct its images, locate the Sun and estimate how long the record has been in space.
The playback guide starts with a drawing of the disc and stylus. Binary marks encode one rotation as 3.6 seconds, using the hydrogen atom’s transition as a unit of time, and show that the record should play from the outside in. NASA says the upper-right diagrams then show how an analog signal can be rebuilt as a picture, including a sample image with a circle to check the proportions.
The lower-left diagram maps the Solar System against 14 pulsars and gives their periods, offering a way to identify where the spacecraft came from. The cover also carries a tiny sample of uranium-238. Because the isotope decays at a known rate, measuring it against its daughter products could provide an age check; NASA gives its half-life as about 4.51 billion years.
The record itself holds sounds from Earth, music, images and greetings in 55 languages. The cover is the clever part: it tries to provide a decoding key based on physical references rather than a shared spoken language. That is an attempt at communication with a hypothetical finder, not evidence that anyone will encounter or decode it. [NASA’s guide to the cover](https://science.nasa.gov/mission/voyager/golden-record-cover/) explains the diagrams; [its Golden Record overview](https://science.nasa.gov/mission/voyager/voyager-golden-record-overview/) describes the message and its contents.
Image: Voyager Golden Record cover, photographed in 1977. Credit: NASA/JPL-Caltech ([image page](https://science.nasa.gov/image-detail/voyager-record-cover-446eb9/)).
~Space ~Voyager
