Talk about Johnny One-Note

September 10, 2003 8:20 AM

In space, you can hear a black hole sing (WaPo link). Using the Chandra X-Ray Observatory, astrophysicists have detected a supermassive black hole in the Perseus Cluster which has been "playing" a B-flat for 3 billion years.

Fascinating as this seemingly counterintuitive discovery (sound carrying through space) is, the real significance lies in that these "sound waves" may explain why the superhot gases in such regions aren't cooling down and forming more stars.
posted by GreyWingnut (19 comments total)

astrophysicists have detected a supermassive black hole in the Perseus Cluster which has been "playing" a B-flat for 3 billion years.

This is the best thing I have read all week.
posted by the fire you left me at 8:21 AM on September 10, 2003

With all the struggles NASA is going through right now, I'm just thrilled to see that the science missions of the agency (in conjunction with their academic partners) keep on keepin' on.
posted by GreyWingnut at 8:26 AM on September 10, 2003

My understanding is that we aren't detecting sound but x-rays, which can travel through a vacuum (unlike sound).
posted by Outlawyr at 8:27 AM on September 10, 2003

the scientists are detecting the signature of ripples through a gaseous medium, so the sound is, in fact, sound. Of course they're not *hearing* this from outer space, but rather seeing those ripples in the medium through x-rays. But presumably if you were sitting in that gaseous cloud, took off your helmet, in the few seconds before a massive case of exposure-induced blues, and if you could hear 57 octaves below middle C, uh, well, you'd hear it. I guess it's sort of the cosmic equivalent of the whole tree falls in the woods thing.
posted by condour75 at 9:43 AM on September 10, 2003

Indeed. And, for a wheeze, they decided to see if they could figure out what those X-rays "might sound like". This is nothing more than the artificial colouring techniques, but using sound instead. Nothing to see here, surely?
posted by kaemaril at 9:45 AM on September 10, 2003

This isn't counterintuitive. Sound still doesn't travel through a vacuum. The sound wave generated is traveling within a gaseous bubble.
posted by linux at 9:46 AM on September 10, 2003

And, for a wheeze, they decided to see if they could figure out what those X-rays "might sound like".

More like the x-rays revealed a concentric sound wave ripple, and by measuring the pulse determined its strength and note.

There is nothing artificial about it.
posted by linux at 9:49 AM on September 10, 2003

The sound waves travel hundreds of thousands of light years through the cluster, which is still PFC. On the Chandra site they have an MPEG cartoon showing high energy particles from the black hole sweeping out the cavities and the subsequent sound wave (1.4meg MPEG/QT). Illustrations, and more animations.
posted by eddydamascene at 9:53 AM on September 10, 2003

This is so beautiful - it challenges our assumptions about perception, or at least the rate at which we perceive our existance. I liken it to the John Cage performance underway in Germany (npr link). Is there any being that can perceive these events in a way different than we?
posted by mouthnoize at 11:42 AM on September 10, 2003

Looks like the Pythagoreans were right about that whole music of the spheres thing.
posted by fidelity at 11:55 AM on September 10, 2003

it challenges our assumptions about perception

Not to be a total azz, but what assumption(s) about perception does this challenge?
posted by Outlawyr at 11:56 AM on September 10, 2003

Am I the only one who sees a relationship with this story?
(Like, "the extreme bass sound known as infrasound produces a range of bizarre effects in people", and if THIS story is accurate, the universe is constantly hitting us with it?)
not gonna call doubles, 'cause nobody checks for new comments on 2-day-old threads anymore...
posted by wendell at 1:30 PM on September 10, 2003

Is there any being that can perceive these events in a way different than we?

The frequency of the sound waves is around 2 femtoHerz, which means you would have to sit still for eighteen million years in order to hear one cycle. If someone parks in front of your house and starts pumping bass at this frequency for 3 billion years, that's like less than half a second of a three minute song.

the universe is constantly hitting us with it

The sound can't escape the cloud of gas that it is created in. Chandra is observing it indirectly.
posted by eddydamascene at 3:29 PM on September 10, 2003

The sound wave generated is traveling within a gaseous bubble.

Rock 'N Roll always does that to me.
posted by HTuttle at 3:38 AM on September 11, 2003

Saying a 2 femtohertz wave in an interstellar medium is a "sound wave" is like saying that ocean waves are "sound waves." Ocean waves are also too low-frequency for us to hear, so we don't call them "sound waves." (The surf noise we hear is generated when the waves collide with the shore, and is higher frequency than the waves themselves.) It's technically correct, I suppose, but "sound" implies that you can hear it.
posted by kindall at 8:29 AM on September 11, 2003

kindall: not quite. Ocean waves are transverse waves, while sound and these are longitudinal pressure waves. It's fair to call them sound waves, though I'd prefer the word "acoustic" which has a broader meaning than stuff you can hear.
posted by ptermit at 9:51 AM on September 11, 2003

Point taken. Let's call 'em longitudinal pressure waves, then.
posted by kindall at 10:30 AM on September 11, 2003

My point exactly.

I think.
posted by Outlawyr at 6:09 PM on September 11, 2003

My junior high school science textbook had a rather silly error in it, as I recall; it confused the audible and electromagnetic spectra. Contrary to popular belief, the spectrum of electromagnetic radiation does NOT include
the sonics. There is no reason to even mention such a thing on a chart of the electromagnetic spectrum. No matter how high pitched a sound one makes, it's still vibrations of air (or other media) molecules -- it'll never be a photon. No matter how low-frequency the radio wave is, it's still an electric and magnetic field - it'll never be a sound. No matter how high you scream, it's not going to come out blue.

The error is made on this otherwise wonderful chart, as well:
http://www.ntia.doc.gov/osmhome/allochrt.html
posted by dmd at 10:03 PM on September 11, 2003