Space is a virtual vacuum, in which sound does not propagate. Indeed, sound is an oscillation of pressure transmitted through a solid, a liquid or a gas. Interstellar and interplanetary space being empty, there is no way for any sound to exist out there. While this would make any of your favourite sci-fi space fight movie scenes sound terribly boring if they were a bit closer to reality, this doesn’t necessarily mean that there is nothing to be heard.

Radio Astronomy

Radio astronomy (a particular field of astronomy that studies celestial objects at radio frequencies) was born in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. It led to various discoveries, and the creation of new classes of astronomical objects, such as pulsars, quasars and radio galaxies.

The famous SETI program is, for example, using radio telescopes in the search for a possible extra-terrestrial life.

Of course, this radio waves are not sounds (they are electromagnetic waves, like visible light), but just like any radio transmission, they can be converted to sounds we can hear. This principle is used everyday by radio stations; you won’t hear anything as long as you don’t have the appropriate equipment.

Let’s face it: you cannot really call what astronomers are observing music (in fact, astronomers are not even converting radio waves to audible frequencies, they are producing images, much more valuable to them). When listening to a star, most of the time you will only hear something called white noise. You could also listen to a «radio noise storm» on Jupiter, due to its interaction with its volcanic moon Io. Here is an example:


The Voyager Recordings

The Voyager Program is a series of U.S. unmanned space missions, consisting in a pair of probes, Voyager 1 and 2, launched in 1977. They were originally designated to study Jupiter and Saturn, but they were able to continue their mission into the outer solar system.

The probes produced a huge amount of data, including the first close-up color photos of the major planets.

Back in 1992, the NASA even produced «Voyager Recordings: Symphonies of the Planets». The specially designed instruments on board the Voyagers performed special experiments to pick up and record electronic vibrations, all within the range of human hearing. The recordings come from various sources:

interaction of the solar wind with the planet’s magnetosphere, the magnetosphere itself, trapped radio waves bouncing between a planet and the inner surface of its atmosphere, electromagnetic field noise within space itself, charged particle interactions of the planet, its moons, and the solar wind, and charged particle emissions from the rings of certain planets.

As you will hear in the following videos, here you have something much closer to actual music (dark ambient like I would say !):




Close your eyes, and Bon Voyage !

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