What does a black hole sound like?

23 Aug 2022

The Perseus black hole. Image: NASA/CXC/SAO/K Arcand/SYSTEM Sounds (M Russo, A Santaguida)

NASA captured the pressure waves sent out by the Perseus black hole and translated these signals into a range that can be heard by humans.

If you’ve ever wanted to know what a black hole sounds like, NASA now has the answer in a format that we can hear.

The space agency shared a sonification – or a translation of astronomical data to sound – of a supermassive black hole. The result is as unique and eerie as you might have expected.

NASA said there is a misconception that there is no sound in space because most of space is a vacuum, providing no way for sound waves to travel. However, a galaxy cluster has so much gas that it provides a medium for sound to travel.

The new sonification relates to sound waves coming from the black hole at the centre of the Perseus galaxy cluster, discovered in data from NASA’s Chandra X-ray Observatory.

In 2003, astronomers discovered that pressure waves sent out by this black hole caused ripples in the cluster’s hot gas that could be translated into a note.

Unfortunately, the note can’t be heard by humans as it is far too low, “some 57 octaves below middle C” according to NASA.

The new sonification is significant because it revisits the sound waves discovered years ago and makes them audible for the first time.

The sound waves were extracted in radial directions, or outwards from the centre. These signals were then resynthesised into a range that humans can hear by scaling them upward by 57 and 58 octaves above their true pitch.

“Another way to put this is that they are being heard 144-quadrillion and 288-quadrillion times higher than their original frequency,” NASA said.

The radar-like scan that can be seen around the image of the galaxy cluster shows how the waves are being emitted in different directions.

Sound is being captured across the cosmos by NASA, not just in the Perseus cluster. The agency has also released a sonification of the black hole located at the centre of the galaxy Messier 87, or M87.

This sonification uses data captured from several telescopes and maps the wavelengths into different audible tones, creating a more pleasing note for the ears.

The black hole in M87 was famously captured in an image by the Event Horizon Telescope in 2019, marking humanity’s first ever glimpse of a black hole.

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Leigh Mc Gowran is a journalist with Silicon Republic