Washington, Sept 11: The voice of a black hole is a deep, deep bass, 57 octaves below middle C and far beyond the hearing range of humans.
The Chandra X-ray Observatory has picked up sound waves for the first time from a cluster of galaxies 250 million light years away.


Astronomers at the Institute of Astronomy in Cambridge, England, discovered the sound waves while analyzing the Chandra images of the Perseus cluster, an immense grouping of galaxies held in formation by the powerful tug of a supermassive black hole.


Andy Fabian, a professor at the Institute of Astronomy, said a close study of the fine detail collected by Chandra shows ripples in the X-ray pattern that are caused by sound waves excited by the energy from the black hole.



He said the sound produced by the black hole is a B flat, the same pitch as a key near middle C on the piano. But the song of the Perseus Black Hole is 57 octaves below that middle C. This is a tone frequency more than a million, billion times deeper than the limits of the human ear, said Fabian.

The voice of the black hole is detected by analyzing the pattern of X-rays coming from superheated gases in the Perseus galactic cluster, said Fabian.


Squeezed by the gravitational pull of the black hole and the galaxies in the cluster, gases are heated to 50 million degrees, hot enough to generate X-rays. A surge of sound waves adds heat energy, causing a slight change in the pattern of X-rays.

"Sound consists of pressure waves," said Fabian. "In the gas of the Perseus cluster, the higher pressure means more X-ray emission."


In effect, the sound waves cause bright and dark emissions of X-rays moving in rings away from the black hole center like ripples on the surface of a pool. Bureau Report