Black holes are popular because scientists are after them because they find them as a laboratory for "quantum gravity" or for testing fundamental theories explaining how the universe works. In 2003, astronomers discovered sound waves from a black hole, giving us a glimpse of how these massive cosmic bodies sound.
Black Hole Sound
Two decades ago, astronomers, for the first time, were able to retrieve sound waves from a black hole 250 million light-years away. NASA shared the chilling audio from a supermassive black hole to the public.
In order for the acoustic waves emanating from the black hole at the heart of the Perseus cluster of galaxies to be audible to human ears, they had to be transposed up 57 and 58 octaves. The end product is unsettling, similar to many of the space waves that have been converted into audio frequencies. It was eerie, and the black hole seemed a little bit furious.
The supermassive black hole at the center of the Perseus cluster's sound waves was extracted radially, or outwards, and played counterclockwise from the center so that we can hear the sounds coming from it in all directions at pitches that are 144 quadrillion and 288 quadrillion times higher than their original frequency.
The sonic waves are not audible at the moment because of the volume of gas surrounding the supermassive black hole. The waves contain the lowest note ever heard by humans and are much below the threshold of human hearing.
However, the sonification has increased the recording's octave range and added to the black hole notes, giving us an idea of what they would sound like ringing through intergalactic space. The lowest note, discovered in 2003, is a B-flat that is a little over 57 octaves below middle C; its frequency at that pitch is 10 million years. A twentieth of a second is the frequency of the lowest note humans can hear.
What Is a Black Hole?
A black hole is a place or cosmic body where light cannot escape due to the gravitational force being so great. The substance is compacted into a very small space; hence, the gravity is quite strong. This may happen when a star is dying.
Black holes are invisible to humans because no light can escape from them. They can only be found with the use of specialized satellite telescopes.
Black holes can range in size from big to tiny. Scientists estimate that an atom is as minuscule as the smallest black holes. Tiny black holes can have the bulk of a massive mountain. The amount of substance, or "stuff," that an item contains determines its mass.
Meanwhile, a "stellar" black hole may have a mass up to 20 times bigger than the sun. There may be a lot of star-mass black holes in the Milky Way, the Earth's galaxy.
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