The Sonification of 67P

The Sonification of 67P

“Rosetta comet sings loud and clear” (BBC Trending 12/11/14)


I am listening to “The Singing Comet”, a one minute and twenty-seven second sound file released on Soundcloud by ESA (The European Space Agency). It contains what I might playfully describe as an unearthly “clicking” sound and at the time of writing has had over 5 million hits. Along with the file, is this description:


Rosetta’s Plasma Consortium (RPC) has uncovered a mysterious ‘song’… It is being sung at 40-50 millihertz, far below human hearing … To make the music audible to the human ear, the frequencies have been increased in this recording. This sonification of the RPC-Mag data was compiled by German composer Manuel Senfft (


“How do you like it?”, my colleague Amit Guur asks me. We are sat together writing articles for the monthly composers newsletter at Amsterdam Conservatory.


“I’m afraid that I am too busy analysing it to experience it as music”, I say. I lament my inability to enjoy ESAs latest “release”, and feel fundamentally confused about whether or not this is music. Surely, I reason, it’s a matter of context; If you say it’s music, then it is, right?


My confusion over this sound file comes in part from my understanding of the term sonification. Sonification describes the act of turning data sets into sound and it has a unique position in the musical world since it is simultaneously perceivable as both information and artwork. A good example of the emotive power of sonification is the bleep of a heart rate monitor, a vitally useful process which allows us to process heart rate data at a distance to the patient and to process it faster and closer to real-time than if we were simply reading the numerical data on a computer. What happens to our thoughts and feelings when it speeds up or slows down, or even changes to a single tone? If you hear these bleeps on their own, in a piece of techno, or from a reversing bus, they are not necessarily threatening, but when told that the sound comes from monitoring a person’s heart, there is a palpable sense of fear, along with many associations; hospitals and heart problems being just a few.


But I still can’t settle down and just listen to the music of the comet. I am puzzled that this phenomenon that we cannot hear (magnetic oscillations according to the ESA description) could be presented quite so simply as something that we can. To me, it seems a little like transposing a piece of Beethoven five octaves higher and calling it an authentic performance; In my mind, it is already something new.


In this strange new world of sonification, where programmers listen for bugs in programmes and blind people can watch colourful fish in an aquarium, it seems that hearing really is believing. But if I’m told that a sound has a source in nature, will I always believe it? Well it’s not quite that simple; if ESA’s comet song had sounded like Elvis Presley, I think we might be a little more suspicious, either that Elvis is still alive out there somewhere, or that the file was actually a fabrication. It is here that we arrive at the real essence of the question: are we are able to distinguish the difference between natural sounds and composed sounds? This question goes right to the heart of what it means to be a composer, to “organise sound” as Edgar Varèse suggested in his 1966 article “The Liberation of Sound”.


I get the feeling that the role of ESA’s in-house composer Manuel Snefft is becoming more and more relevant to this question. Employing a composer seems a very romantic choice; perhaps ESA felt that giving a musical context to this piece of sonification would help it’s audience to understand it easily. Put simply, in what way can I understand this process as composing? If I take Varèse’s “organised sound” definition, then the MAG data from Rosetta has simply been re-organised by Snefft, keeping relative numerical relationships and effectively “scaling” them somewhere into our audible range. It is not dissimilar to DJ-ing several tracks together from different genres and eras in such a way as to conform to the atmosphere of a particular nightclub.


A criticism that I have leveled towards sonification in the past is that the actual scale is almost never given, as though this were some complex or even mystical process that only a composer was capable of performing, or that the public are not permitted to understand. Perhaps I’m getting closer now to what I find confusing about this business of sonification; It has an uncomfortable air of grandiosity about it which seems out-of-place considering the otherwise careful explanation of scientific standards and methods in ESA’s mission.


It certainly makes for a fascinating analysis, imagining the listener jumping continuously from their abstracted experience of the sound, to it’s highly factual presentation. How are we supposed to feel about this singing comet? If we don’t like it’s songs, does that mean we don’t like the comet?


Anybody can apply for The X-Factor, as long as they’re over 14 years old. We don’t know exactly how old 67P is, but it’s current estimated age is over 4 billion years…

Related Posts

Leave A Comment