There is a lot of confusion about cosmic sounds. Although there is a widespread belief that there is no noise in the Universe, the reality is that there is, and it is quite eerie. It just takes to listen to the new NASA clip where you can actually hear the sound of a black hole 250 million light years away from us, at the center of the Perseus cluster of galaxies.
Is there sound in the Universe?
There has been much speculation as to whether sound exists in the Universe since there is no way soundwaves can travel in the vacuum of it, but the reality is that the gases in the Universe make sound happen. Cosmic objects do emit real sound waves, however, there are two main reasons why we cannot hear them.
The first is that space is a huge vacuum where the distances between one object and another are truly colossal and there is no medium through which they can propagate. On Earth, everything is audible thanks to the existence of a large medium for the propagation of sound waves, which we call the atmosphere. This is composed of myriads of gas particles that are activated by the emission of any sound wave and as a chain reaction, more particles vibrate propagating the sound. On the other hand, in space, this does not exist and any sound wave dies in the vacuum.
The second reason why we would not be able to hear the sounds of the Universe if we were out there is that the sound waves emitted by cosmic objects are actually outside the spectrum audible to a human. This does not mean that they do not exist, but that we cannot perceive them any more than we can perceive ultraviolet light.
The spooky sound of a black hole
Astrophysicists have their ways to turn inaudible into audible, through sonification, the process of transforming sound waves or other electromagnetic waves, to sound waves within the audible spectrum of the human.
There are images that not only can be seen but through sonification, this vision is transformed into sound waves, as in the case of pulsars that have been heard thanks to this method. But there are also cases where the sound waves are real and do not come from electromagnetic waves or light.
NASA has just revealed a clip where you can hear the real sound of the black hole in the Perseus cluster of galaxies. In some ways, this sonification is different from any other made before, as these are actual sound waves from the devouring object.
These were captured by NASA’s Chandra X-ray Observatory, made possible by the fact that, unlike the interstellar vacuum, galaxy clusters have copious amounts of gas enveloping the hundreds or even thousands of galaxies within it, providing a medium for the sound waves to travel.
Of course, the clip does not show the actual sound because if it did, we would not be able to hear it since it is not within our spectrum. To do this, NASA resynthesized the sound in the range of the human ear by increasing the waves by 57 and 58 octaves above their actual pitch so that we can finally hear the eerie sound of a black hole.
Story originally published in Ecoosfera
