Image description: NASA spacecrafts Voyager 1 and 2 both carry this 12-inch gold-plated phonograph record containing sounds and images of life on Earth — just in case they encounter intelligent life.

The figures on the record explain the origin of the spacecraft and indicate how the record is to be played. The contents of the record, chosen by a committee chaired by the late astronomer Carl Sagan, include music, greetings, biological information, animal sounds, and more. The record even includes brain waves of a young woman in love, committee member Ann Druyan. Druyan and Sagan had fallen in love while working together on the project.

The Voyager probes, launched in 1977 and by far the furthest reaching human-made objects, are now at the edge of the solar system. Voyager 1 is over 18 billion kilometers from the Sun, even further away than Pluto. In fact, the craft is reaching the end of the Sun’s influence and is predicted to enter interstellar space around 2015. Both crafts have the batteries to transmit discoveries until about 2020.

Find out what the inscriptions on the Golden Record mean, the messages it contains, and more about the Voyager mission.