![[identity profile]](https://www.dreamwidth.org/img/silk/identity/openid.png){kind=small}
![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
Reprinting the whole story here just in case CNN cleans its archives. I want to keep it.
http://www.cnn.com/2003/TECH/space/09/10/blackhole.music.reut/index.html
WASHINGTON, Sept 9 (Reuters) -- Big black holes sing bass. One particularly monstrous black hole has probably been humming B flat for billions of years, but at a pitch no human could hear, let alone sing, astronomers said this week.
"The intensity of the sound is comparable to human speech," said Andrew Fabian of the Institute of Astronomy at Cambridge, England. But the pitch of the sound is about 57 octaves below middle C, roughly the middle of a standard piano keyboard.
This is far, far deeper than humans can hear, the researchers said, and they believe it is the deepest note ever detected in the universe.
The sound waves are emanating from the Perseus Cluster, a giant clump of galaxies some 250 million light-years from Earth. A light-year is about 6 trillion miles (10 trillion km), the distance light travels in a year.
Fabian and his colleagues used NASA's orbiting Chandra X-Ray Observatory to investigate X-rays coming from the cluster's heart.
Researchers presumed that a supermassive black hole, with perhaps 2.5 billion times the mass of our sun, lay there, and the activity around the center bolstered this assumption.
Black holes are powerful matter-sucking drains in space, and astronomers believe most galaxies, including our own Milky Way, may contain black holes at their centers.
Black holes have not been directly observed, because their gravitational pull is so strong that nothing, not even light, can escape it.
Making waves
So researchers have concentrated on what happens around the edges of black holes, just before matter is pulled in.
When scientists trained the Chandra observatory on the center of Perseus last year, they saw concentric ripples in the cosmic gas that fills the space between the galaxies in the cluster.
"We're dealing with enormous scales here," Fabian said in a telephone interview. "The size of these ripples is 30,000 light-years."
Fabian said the ripples were caused by the rhythmic squeezing and heating of the cosmic gas by the intense gravitational pressure of the jumble of galaxies packed together in the cluster.
As the black hole pulls material in, he said, it also creates jets of material shooting out above and below it, and it is these powerful jets that create the pressure that creates the sound waves.
To scientists, he said, pressure ripples equate to sound waves. By calculating how far apart the ripples were, and how fast sound might travel there, the team of researchers determined the musical note of the sound.
Fabian said the notion of singing black holes might well be extrapolated to other galaxies, but not necessarily to the Milky Way.
Chandra has looked at X-ray emissions from the Milky Way's center, and astronomers believe there is a black hole there, but because it is a young, rambunctious galaxy with lots of activity at its heart, this may interfere with any note our black hole might sing, Fabian said.
http://www.cnn.com/2003/TECH/space/09/10/blackhole.music.reut/index.html
WASHINGTON, Sept 9 (Reuters) -- Big black holes sing bass. One particularly monstrous black hole has probably been humming B flat for billions of years, but at a pitch no human could hear, let alone sing, astronomers said this week.
"The intensity of the sound is comparable to human speech," said Andrew Fabian of the Institute of Astronomy at Cambridge, England. But the pitch of the sound is about 57 octaves below middle C, roughly the middle of a standard piano keyboard.
This is far, far deeper than humans can hear, the researchers said, and they believe it is the deepest note ever detected in the universe.
The sound waves are emanating from the Perseus Cluster, a giant clump of galaxies some 250 million light-years from Earth. A light-year is about 6 trillion miles (10 trillion km), the distance light travels in a year.
Fabian and his colleagues used NASA's orbiting Chandra X-Ray Observatory to investigate X-rays coming from the cluster's heart.
Researchers presumed that a supermassive black hole, with perhaps 2.5 billion times the mass of our sun, lay there, and the activity around the center bolstered this assumption.
Black holes are powerful matter-sucking drains in space, and astronomers believe most galaxies, including our own Milky Way, may contain black holes at their centers.
Black holes have not been directly observed, because their gravitational pull is so strong that nothing, not even light, can escape it.
Making waves
So researchers have concentrated on what happens around the edges of black holes, just before matter is pulled in.
When scientists trained the Chandra observatory on the center of Perseus last year, they saw concentric ripples in the cosmic gas that fills the space between the galaxies in the cluster.
"We're dealing with enormous scales here," Fabian said in a telephone interview. "The size of these ripples is 30,000 light-years."
Fabian said the ripples were caused by the rhythmic squeezing and heating of the cosmic gas by the intense gravitational pressure of the jumble of galaxies packed together in the cluster.
As the black hole pulls material in, he said, it also creates jets of material shooting out above and below it, and it is these powerful jets that create the pressure that creates the sound waves.
To scientists, he said, pressure ripples equate to sound waves. By calculating how far apart the ripples were, and how fast sound might travel there, the team of researchers determined the musical note of the sound.
Fabian said the notion of singing black holes might well be extrapolated to other galaxies, but not necessarily to the Milky Way.
Chandra has looked at X-ray emissions from the Milky Way's center, and astronomers believe there is a black hole there, but because it is a young, rambunctious galaxy with lots of activity at its heart, this may interfere with any note our black hole might sing, Fabian said.
no subject
- Paul B. BSc K:o}
(Not really bothering to apply my acoustics degree to the problem!)
(Does that "K" even look anything like a mortarboard?)
no subject
57 Octaves Down from Middle C?
Now multiply that factor times at least 10.
A shame, though. The concept is enthralling...;>
-Silver
Who Swears He's Seen this Article Somewhere Else... ;>
Re: 57 Octaves Down from Middle C?
a b-flat 57 octaves down from this would be .00000000000000272 hertz.
no subject
no subject
*Our* black hole is more into rap, obviously! =:o>
no subject
Good to see you back, too.
no subject
no subject
no subject
::sighs happily::
no subject
no subject
no subject
no subject
no subject
no subject
no subject
Oooh, a cosmic orgasm!
no subject
no subject
There's a good quote in _Fallen Angels_, by Niven/Pournelle/Flynn (available free for download at Baen.com, everyone) that comes to mind:
---
"A lot of my mundane friends," she said to Alex, "think that explaining a phenomenon 'ruins the magic.' I think the explanations just make it more magical than before. 'Danes live in a world where everything happens on the surface; where everything is a symptom?—like the rainbows. But a cloud of microscopic crystal prisms is as magical as an unexplained rainbow any day."
no subject
no subject