In 1977 NASA launched the Voyager 1 and Voyager 2 space probes to study the outer solar system. Voyager 1 flew by Jupiter, Saturn, and Saturn’s largest moon, Titan. Voyager 2 flew by Jupiter, Saturn, Uranus, and Neptune. After 37 years the probes continue to send data back to Earth as they hurtle out of the solar system.
Each probe contains a gold-plated copper record encoded with images and audio from our planet. It’s fascinating to see the list of sounds that people thought were important enough to use as an interplanetary greeting. It’s like a greatest hits album for our entire planet: birds, the ocean, Chuck Berry, Mozart, a tractor.
The easiest way to listen is probably YouTube. There’s also goldenrecord.org and another option, but I find the YouTube playlist navigation to be easier. There are also official NASA playlists on SoundCloud, but they only include Greetings to the Universe and Sounds of Earth.