“In space, no one can hear you scream,” reads the tagline for the original Alien movie. And that’s true: for the most part, interplanetary space is just a big bag of nothing. But that doesn’t mean it’s completely silent.
Human ears are specially designed to translate changing pressures traveling through a medium. These sound waves are rendered mute once the medium they are traveling through comes to an end (say, when the atmosphere on Earth gives way to the emptiness of space). However, there are plenty of waves that can move through a vacuum. We can then translate these vacuum-friendly waves into sounds that humans can hear.
Over the past few decades, we’ve sent a number of satellites to the far reaches of the solar system. For research and communication reasons, these vessels left with sensors designed to “hear” things like radio and plasma waves that flow freely through interplanetary space. Using a technological intermediary, humans are able to “hear” these space waves as audible sounds.