Sonification, or the translation of data into sounds, is an operation between science and art. Which today is practiced not only in astronomy but also in many other disciplines.
The space between the stars and between the galaxies is substantially empty. So in the cosmos there are no noises, because there is no means that can transmit sound waves. But from celestial objects, electromagnetic waves and other information arrive, which are displayed with different methods: often images (which are static) or tables and graphics, most of the time incomprehensible to those who are not of the trade. Here then the feeling comes into play: in practice, the translation of a certain set of data into sounds, which are perceptible from the human ear.
Daily and astronomical sounds. “After all, it is something we often use in our everyday life,” explains Sandro Bardelli, astronomer at the National Institute of Astrophysics-Astronomical Observatory of Bologna. “For example, we think of the sound that emits our smartphone when a message arrives, a medical appliance that emits a signal if there is an out of place parameter, or to the various acoustic notices that use the line drivers”.
One of the sectors of science in which this technique is more used is astronomy. «When in our profession we draw a graphic designer, we compare a certain physical quantity with another: for example, the space covered according to the time. We can also make a three -axis graph, to compare three quantities together, but it is already so complicated. If there are even more variables, and they are associated with many objects, it is impossible to represent them. Sonification is then useful because it allows you to put
Together many different parameters for many objects ». Thinking about music, it is one thing to listen to a jazz trio, of which you can clearly distinguish the individual tools, one account is to evaluate an orchestra with a hundred elements as a whole.
From nebulas to galaxies. In astronomy there are many examples of feeling. One of the modern pioneers of this technique is the Chandra X-Ray Observatory of the NASA. Since 1999, this space telescope has observed the universe in X -ray, revealing the most violent and warm phenomena of the cosmos: stars that explode, supermaxicci black holes that devour matter and clusters of galaxies wrapped in gas to millions of degrees.
Even our star, the sun, has its own “voice”, and the Solar Orbiter probe of the European Space Agency (ESA) has allowed us to listen to it. The video below combines the data collected in the last 3 years by two different tools.
The images of the Solar Crown (the outermost atmosphere of the sun), of yellow color, were captured by the Extreme Ultraviolet Imager (EU) tool. These images are superimposed on blue circles, which indicate the position and strength of solar brights, as recorded by the X -ray spectrometer Stix. The size of each circle is proportional to the intensity of the shine.
The audio that accompanies the images is a subification based on two parameters. The constant basic hum represents the distance of the probe from the sun: given that Solar Orbiter follows an elliptical orbit, the hum is stronger when the probe is closer to the sun and more quiet when it goes away. The brilliant, however, are represented by metal sounds similar to “clinks”. The acuteness of these sounds corresponds to the energy of brilliant: the more powerful a bright, the more the sound is acute and defined.
The new Webb spatial telescope has also launched into the feeling, with a series of audio of nebulary and galaxies. In the video below, for example, the feeling concerns two different images of the nebula ring of the South (NGC 3132): one in the infrared nearby (left in the video) and one in the medium infrared (right). At the center of this planetary nebula, two stars orbit one around the other: a star is weaker and is at the end of his life: for thousands of years he has expelled the layers of gases and dust that today form the nebula; The other, larger and brighter star, has “shuffled” and modeled these expulsions with its strength of gravity. Thanks to this musical translation it is possible to “listen to” and clearly distinguish the two stars and the materials of material that surround them, perceiving how different appears in the two types of infrared light.
NASA has always undergone the radio waves issued by Saturn and collected by the Cassini probe during its mission. These emissions are closely connected to the spectacular auror that form near the planet’s poles, a phenomenon very similar to the northern and austral auror that we admire on earth.
The Sonicosmos project. Sandro Bardelli dedicated himself to subscribing the cosmos thanks to a work that began between 2003 and 2005, which provided for the observation of galaxies located in the southern constellation of the Sestante. «With the Very Large Telescope, in Chile, I had participated in a series of distance measures of galaxies, about 70,000, to establish the stellar formation rate as varied inside them.
In fact, the more you look far away you go back in time, and then see how the stellar formation changes in different eras of the past. For the feeling, of the 70,000 observed galaxies we have selected about 8,000, so that they were homogeneous as absolute brightness, that is, as a light emitted. Then, for each of them, we associated the height of the sound with the mass, the intensity with the brightness, the duration and the stamp at the stellar formation rate and with the stereo, the Dolby Surround, we have given the idea of the coordinates, that is, of the position of the galaxies in the sky. At that point we went back in time. Every second are 4.5 million years, up to the limit of our data, which is 7.5 billion years ago: let’s move from today to an era in which the star training was much higher. To us researchers, listening to these sounds immediately makes it clear what is the parameter that varies the most, which has more peaks etc. ».
The feeling, created by Sandro Bardelli, Giorgio Presti, of the Department of Music Informatics of the State University of Milan, and by the sound artists Claudia Ferretti and Maurizio Rinaldi, however, became much more: it came out of the workshops and has transformed into a show that unites science and art called Sonicosmos. With the collaboration of Stefano Mazzanti, Light Designer, it is now also an artistic installation presented at various performing arts festivals.
Help to people in difficulty. However, that the underground is more than an intellectual or artistic game, it demonstrates a 2023 document of one (the United Nations Office for the business of the Extractmosferic space) where it is underlined how it is an effective tool for research, scientific dissemination and inclusiveness. “The feeling of the data to us researchers is used to have an immediate impression of the set of data, because we can listen to all the galaxies of our sample at the same time with their individual characteristics,” explains Bardelli. «But it is also a formidable instrument of inclusiveness, for partially sighted or blind people. If one of them wants to read a newspaper article can in fact use some software that translates the words written in audible words. But a graphic designer or figure how can I tell him? The feeling allows me. “
From geology to the environment. This method of processing data adapts very well to other scientific disciplines.
For example, the seismic events produced by the eruptions of the Kilauea volcano, in Hawaii, were evident by Leif Karlstrom (University of Oregon in Eugene) and colleagues for ten years, up to the collapse of the crater that occurred in 2018.
The earthquakes that occurred in Iceland from 2013 to 2023 found their sound example thanks to Cyril Kaplan and Vlastimil Koudelka, two psychologists, respectively of the Karlova University and the Mental Health Institute of the Czech Republic, which underlined how the Sonification, accompanied by a video, provides a strong multisensory experience and allows us to “perceive” the data in a way. deep.
And again, if the increase in the co2 In the atmosphere for many it is an abstract concept, feeling with your ears how this parameter has varied and, in parallel, how the average temperature of the planet has been raised really scares. The climate change of the last fifty years is, literally, deafening.
“This way of enjoying scientific data”, remarks Sandro Bardelli, “has a strong, very emotional impact on the general public. When I speak of global warming, some look at me sufficiently. But when I listen to them the unsuccessful data are terrified of it, because they understand how much this change, for a few decades, is very fast ».
With all its potential, the feeling, when it is presented to a general audience, needs an explanation. “The first thing to clarify”, specifies Bardelli, “is that people think they feel the sound, for example, of galaxies. This is not the case. We collect different types of data and transform them into sounds: the universe, or nature, give us information and we build the tool to make them feel. And the choice of the sounds and stamps we use is … arbitrary. The second thing is that if I have a fact that increases continuously I have to use a sound that increases the same way. So I can’t use a musical scale. This is why there is no talk of music, but of sound ». The sound of the universe.
