Sounds of Voyager 1

Voyager 1, the probe carrying a time capsule and greetings to other life forms, that were recorded as the craft crossed a turbulent boundary on the fringes of the Solar System.

Launched in 1977, Voyager 1 is now 13.92 billion kilometers (8.7 billion miles) from the Sun and has traversed the "termination shock," part of the frontier zone between the Solar System and interstellar space.