The golden message currently leaving our solar system

The Design of an Interstellar Archive

In the summer of 1977, NASA launched Voyager 1 and Voyager 2 to explore the outer giants of the solar system: Jupiter, Saturn, Uranus, and Neptune. Recognizing that the gravitational assists propelling these probes would ultimately fling them out of the Sun's gravitational grip and into interstellar space, NASA commissioned a team to create a message for any extraterrestrial civilization that might cross their paths. Astronomer Carl Sagan chaired the committee, assembling a small group that included artist Jon Lomberg, creative director Ann Druyan, science writer Timothy Ferris, and astronomer Frank Drake.

The committee had only a few months to decide how to summarize an entire planet. Rather than relying on magnetic tape, which degrades over time and is vulnerable to radiation, the team chose twelve-inch phonograph records manufactured from gold-plated copper. Each record is housed in an aluminum protective jacket electroplated with a micro-thin layer of ultra-pure uranium-238. Because uranium-238 decays at a known, steady half-life of roughly 4.47 billion years, any potential finder capable of measuring the isotopic ratio can determine the approximate date of the record's manufacture.

Two identical copies were pressed: one mounted to the exterior chassis of Voyager 1 and the other to Voyager 2. Packaged alongside each disc is an aluminum cover, a phonograph needle, and a cartridge, providing the mechanical components necessary to retrieve the recorded data. Designed to withstand the abrasive dust, cosmic rays, and extreme thermal conditions of deep space, the records are estimated to endure for billions of years, potentially outlasting Earth and the Sun.

Decoding the Cover: Hydrogen Clocks and Pulsar Maps