Earth made a mixtape. Then sent it away.

Each Voyager spacecraft launched in 1977 carrying a 12-inch gold-plated phonograph record. A committee chaired by Carl Sagan selected natural sounds, music, greetings in 55 languages and 115 encoded images. The object makes selection unusually visible. No collection of this size can stand in for every place, person or experience on Earth. Read it instead as a proposed introduction, made by particular people at a particular time. A greeting offers a voice; a photograph presents a chosen view; a recording gives a few minutes to one performance. They share a surface without doing the same job. The interesting question is what the combination allows a listener to encounter.

NASA’s music list includes Chuck Berry’s “Johnny B. Goode,” “Flowing Streams” performed by Kuan P’ing-hu, and Blind Willie Johnson’s “Dark Was the Night.” You can already see the editorial range in those three entries, before hearing a note. The approximately 90-minute music selection is one part of the record, alongside the greetings, other sounds and images; it is not the duration of all its contents. Choosing a composition also means choosing a performance and the time it occupies. A record can preserve that encounter with music, but it cannot carry all the context that gave the music meaning. A listener would have to begin with the sound itself.

The records travelled with a protective aluminium jacket, cartridge and needle. Playback still needed instructions. A cover drawing puts the stylus at the beginning and indicates outside-to-inside playback; the audio is designed for 16⅔ revolutions per minute. Another diagram uses a hydrogen transition to define a time unit, while a map locates the solar system relative to 14 pulsars. The engineering task is to provide a starting point without assuming shared words or familiar equipment. That is why the cover deserves as much attention as the playlist. A message has a practical threshold: its recipient must work out what kind of object it is, and how to obtain anything from it.

The 115 images are encoded as analogue signals. The cover explains how to reconstruct a picture from 512 vertical lines, and reproduces the first image: a circle used to check the proportions. Before a stranger can inspect a portrait of Earth, they have to solve the format. The circle is a modest but revealing choice. If it comes out as an oval, the recipient has a reason to check the reconstructed image’s width-to-height ratio before interpreting its contents. None of these instructions guarantees a successful encounter or understanding. Their appeal is the care put into making one possible. The 1977 record asks both what we would say to an unfamiliar audience and which assumptions we would need to explain first.