What do black holes sound like? Like a vision of heaven or hell

Scientists unveil the at times celestial, and others moanful, sounds of black holes in deep space

Nasa has released amazing audio from a pair of black holes that was captured by one of its space telescopes.

So what does a black hole sound like? Hell — or maybe heaven. Based on new work by the Smithsonian Astrophysical Observatory’s Chandra X-ray Center, it depends on the black hole, and how you listen.

Vacuous space, for the most part, lacks a continuous medium for the transmission of sound waves.

But sound is just one kind of wave, and Nasa and the Chandra X-ray Center have built up a catalog of celestial “sonifications,” taking the emissions of space objects observed in visual light, X-ray, and other parts of the electromagnetic spectrum, and converting the patterns to audible frequencies we can hear.

Some of the sonifications rendered so far include the “sounds” of our galaxy’s core, supernovae, and nebulae such as the “pillars of creation.”

But in honor of Black Hole Week, Nasa and the center have shared two new sonifications of black holes.

The first is the black hole at the center of the 53-million-light-year-distant galaxy Messier 87, which in 2019 became the first black hole ever imaged using the Event Horizon Telescope. The sonification of the Messier 87 black hole incorporates X-ray, visual light and radio wave observations, converting them to audio waves that are surprisingly harmonious and ethereal.

But the second black hole is a different story.

The black hole at the heart of the Perseus galaxy cluster is different from most other targets for sonification, because it sits in a cloud of hot gas permeating the cluster. It actually generates ripples in that gas more properly classified as “sound” than the X-rays and other light from Messier 84.

The trick for Nasa and the Chandra X-ray center was learning to shift the pitch of the Perseus black hole’s sounds into the range of human hearing. The black hole’s sounds naturally vibrate 57 octaves below middle C on the piano, and so they had to be scaled up by 57 to 58 octaves — an astonishing 288 quadrillion times higher than their original pitch.

The results are wildly different from the Messier 84 sonification. Where Messier 84 was sonorous and celestial, the Perseus signification is at times discordant, dark, and dirgeful, a sound perhaps more expected from a perfectly dark maw of an all-consuming abyss than the dulcet tones of Messier 84.

The significations were created as part of Nasa’s Universe of Learning program, which aims to inspire students and self-directed learning about space, astronomy, and physics.