The movie “Alien” had the catchphrase, “In space, nobody can you hear you scream.” The fact that in space, there is a vacuum which means that sound cannot travel as it can on Earth. However, there are exceptions. The vast majority of space may be silent, but that does not mean that it is inactive. In space, there is a lot going on.
If we take the example of a supermassive black hole, located in the Perseus cluster of stars, we can see gas being thrown out into space. If it were possible to be in the area listening to this, we would hear nothing. But that is because, the sound that gas is making is outside the range of our hearing.
However, all is not lost. Scientists observing this event have been able to measure the pressure waves being ejected and have come up with the sound it is most likely to resemble. And what is it? They state it would sound like a “burp”. I suppose that since black holes “swallow” everything they come into contact with, you might expect them to have better table manners! Just whilst we are on the subject of black holes, they apparently do eject radiation which is known as Hawking radiation after the famous theoretical physicist, Stephen Hawking. But that is another story.
Seriously, the researchers have been able to quantify these pressure waves into something understandable to those who know music. They have equated it to a low B Flat which is around 57 octaves below Middle C. This is out of the range of human hearing. One of the scientists has equated it as a “growling and burping entity.”
One important thing to note is that although space is a vacuum, other planets in our solar system and almost certainly exoplanets, have atmospheres, some much denser than our own. Wind and other atmospheric effects would produce sounds, but possibly not as we know it, to coin a phrase from Mr Spock. Mars has a thinner atmosphere than the Earth, but one of our Mars rovers has heard the sounds of Mars. More such sounds will no doubt be recorded elsewhere in the future.
John Pullen 