Bass In Outer Space!
(Black Hole Makes Deepest Note Ever Honoring The
Deep Voice Of The
Man In Black?)
Sep 10,10:54 AM ET
By Robert Roy Britt
Senior Science Writer, SPACE.com
(a realted story?)...
Astronomers have detected the deepest note ever generated in the cosmos,
a B-flat flying through space like a ripple on an invisible pond. No human
will actually hear the note, because it is 57 octaves below the keys in
the middle of a piano.
The detection was made with NASA's Chandra X-ray Observatory and announced
at a press conference today.
The note strikes an important chord with astronomers, who say it may help
them understand how the universe's largest structures, called galaxy clusters,
The sound waves appear to be heating gas in the Perseus galaxy cluster,
some 250 million light-years away, potentially solving a longstanding
mystery about why the gas surrounding this cluster and others does not
chill out as existing theory predicts.
The gas is apparently dancing excitedly to the eons-long drone of a deep
Black hole music
Astronomers were not surprised to find the supermassive black hole making
a strong sub-bass sound. Though these greatest known matter sinks are
by nature dark and invisible, they create bright and chaotic environments
in which many forms of radiation -- from radio waves to visible light
to X-rays -- have been recorded. These electromagnetic waves all travel
at the speed of light.
Sound waves are similar, but they travel far more slowly and are more
physical in nature. Sound you hear, for example, can be produced by the
visible compression and expansion of a stereo speaker. The waves physically
compress the stuff through which they move, be it air, water, or hot interstellar
Other studies have shown that the riotous activity around black holes
-- where gas is accelerated to nearly light-speed -- produces many notes
that are, all together, much like music. Collectively, the cosmos produce,
scientists believe, a cacophonic symphony of inaudible tunes.
Musical production appears to be ubiquitous in Nature. Scientists often
call it flicker noise, and it has also been detected in the X-ray outputs
of magnetic fields within our solar system. Even Earth hums its own tune.
Musical analogies are found in everything from seascapes to brainwaves.
Way out of range
The 53 hours of Chandra observations revealed a note that is more than
a million billion times deeper than what you can hear.
"We have observed the prodigious amounts of light and heat created
by black holes," said Andrew Fabian of the Institute of Astronomy
in Cambridge, England, and leader of the study. "Now we have detected
"The Perseus sound waves are much more than just an interesting form
of black hole acoustics," said Fabian's colleague Steve Allen. "These
sound waves may be the key in figuring out how galaxy clusters grow."
Scientists had previously observed large amounts of hot gas infusing clusters.
Given what's known, the gas should cool over time, however. Cooler gas
would create areas of lower pressure near the center of a cluster, causing
fringe gas to fall inward. In the process, trillions of stars would form.
This isn't what astronomers see when they look at clusters, though.
The Perseus cluster is the brightest known in X-rays, making it a good
target for study. It has two large, bubble-shaped cavities that extend
away from a central black hole. The cavities are formed by jets of material
ejected from the black hole's surroundings, and the jets have been suspected
of heating the outlying gas. But scientists couldn't see how.
A special image-processing technique was used to bring out subtle changes
in brightness that revealed the presence of ripples -- the sound waves.
Fabian and Allen figure the sound waves, observed spreading out from the
cavities, heat the gas. The amount of energy involved is staggering, equal
to what would be produced if 100 million stars exploded.
A single, long-sounding note is produced by a sound wave in which the
waves are the same size and shape continuously. The newfound note has
been sounding, the researchers say, for about 2.5 billion years.