The publication of the first photo of Sagittarius Ahas become the big scientific news of the month of May. And possibly one of the most important of the year. And even of the decade! Thanks to the work of an international team of scientists over the years, we have been able to see the black hole located in the center of our galaxy. And if that wasn't exciting enough, now we can hear it too, thanks to sonification by NASA's Chandra X-ray Observatory.
It should be noted that, in reality, we neither see nor hears. The image taken by the Event Horizon Telescope consortium is the result of computer processing the radiation detected around the black hole as it engulfs matter around it. As for sonification, it is a second processing step in which a higher volume is assigned to the zones with the highest brightness and a higher sound frequency to the zones closest to the black hole.
It is not the first time that these scientists have performed the sonification of an astronomical image. They have also done it with the first black hole that was photographed, the M87*, as well as with the Tycho supernova remnant or the Perseus cluster. In addition, other researchers have sonified other astronomical phenomena, such as the Martian sunrise, or even biological ones. This is the case of those who recently turned the patterns of a spider web into music. Even the first decimals of the number pi have become a melody!
This is the sonification of the black hole in the center of the Milky Way
In this case, the scientists started from the image of the Sagittarius black hole A* published in recent days.
The entire photograph was divided as if it were a clock face, so that the sonificationn began at twelve o'clock. Then, moving clockwise, the melody was obtained, so that the brightest areas were represented with greater volume. In addition, the faster moving regions closer to the black hole were assigned to higher sound frequencies.
The sonification was taken by sweeping the image clockwise
On the other hand, as explained by those responsible for the sonification in a statement, the result “was processed in a special way to allow a listener to hear the data in 3D stereo sound“. This means that “sounds appear to start straight ahead and then move clockwise to one ear and then the other as the sweep is performed.”
Like the image, all of this corresponds more to the matter in the event horizon than to the black hole itself. Nothing can escape black holes, not even light, so they are actually all darkness. What is represented is the event horizon, which corresponds to the region from which nothing can escape being engulfed. That matter spinning around the black hole just before it absorbs it is what we have been able to see and hear.
And this is just the beginning. That's two now, but thanks to techniques that are clearly being perfected, we could soon have many more black hole pictures. And why not? Also an acoustic representation of them.
