Astronomy is not all about pretty pictures, because some people can’t see them. The process of turning pictures into sound, or sonification, has been around since the mid-1970s. Researchers first applied this technique to the area around the supermassive black hole Sagittarius A* in 2020, and have expanded it to other targets in later years.

The latest Chandra X-ray Observatory project, the fifth in the series, involves actual sound waves for the first time. Space is generally not dense enough for sound to travel, but the center of galaxies – such as the Perseus Galaxy Cluster – has enough material for sound waves to travel through, and these are recorded in the new sonification. However, the sound waves are very faint, so to produce something audible by a human, the data was boosted by almost 60 octaves, 288 quadrillion times louder than the original. That’s 28 with fifteen zeros.

The sound is plotted radially, to show that the cluster’s gas extends different amounts in different directions. I’ve listened to it and my impression is that it’s spooky. Beth agreed and also said that it sounded like a deep whale song mixed with zooming race cars. We’ll have a link to the recording in the show notes for today’s episode at our website, DailySpace.org.

Another sonification released by the team is of the famous black hole in Messier 87. This one includes three different tracks showing how the object looks in X-ray, visible, and radio light. For this sonification, instead of actual sound waves, “each wavelength is mapped to audible tones”. One can hear (and see, as the sonification is accompanied by a picture of each wavelength and a waveform) the differences in the intensity of light produced by the different wavelengths of this object. I found this one more pleasant to listen to, but it is more processed compared to the Perseus one.

More Information

CXO press release

VIDEO: Black Hole Sonification Remix (CXO)