he Sound of a Black Hole Astronomers using the Chandra X-ray Observatory have di
ID: 2225320 • Letter: H
Question
he Sound of a Black Hole Astronomers using the Chandra X-ray Observatory have discovered that the Perseus Black Hole, some 250 million light years away, produces sound waves in the gaseous halo that surrounds it. The frequency of this sound is the same as the frequency of the 59th B-flat below the B-flat given in the table. Chromatic Musical Scale Note Frequency ({ m Hz}) { m Middle,C} 261.7 { m C^sharp (C-sharp), m D^ lat (D-flat)} 277.2 { m D} 293.7 { m D^sharp, E^ lat} 311.2 { m E} 329.7 { m F} 349.2 { m F^sharp, G^ lat} 370.0 { m G} 392.0 { m G^sharp, A^ lat} 415.3 { m A} 440.0 { m A^sharp, B^ lat} 466.2 { m B} 493.9 { m C} 523.3 Part A How long does it take for this sound wave to complete one cycle? Give your answer in yearsExplanation / Answer
The black hole is situated in the center of a galaxy amid a group of thousands of galaxies collectively called the Perseus Cluster and located 250 million light years from Earth (meaning it took the light from these galaxies 250 million years to reach us). The sound waves coming from it are in the form of a single note, so rather than a song it is really a drone.
Using the piano keyboard's middle C note as a reference point for the middle of the piano key music range, Fabian's team determined the note is a B -flat. On a piano, the B-flat nearest middle C is located midway between 1/8th and 2/8th of an octave away. In musical terminology, this B flat is 1-1/2 steps from middle C.
The Perseus cluster black hole's B-flat, by contrast, is 57 octaves below middle C or one million, billion times lower than the lowest sound audible to the human ear! In terms of frequency (the time it takes a single sound wave to pass by), the lowest sounds a person can hear is 1/20th of a second. The Perseus black hole's sound waves have a frequency of 10 million years!
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