The Sound of a Black Hole 78
Snags writes "Astronomers have used the Chandra X-ray Observatory to observe the deepest, lowest-frequency sound waves ever observed. By my calculations, the 'B-Flat 57 octaves below middle-C' has a period of 9.8 million years. Despite arguments that explosions in space movies should be silent, it is legitimate to call these sound waves because at that frequency, particles of space dust can 'see' each other through gravity. These notes are 'over a million billion times deeper than the limits of human hearing', so to call it infra-sound would be a bit of an understatement."
That explains! (Score:5, Funny)
Re:That explains! (Score:2)
My vivid imagination... (Score:4, Funny)
the sound I heard in my mind was "oh shit there's a black hole!"
This would be a "RTFA". It *is* sound. (Score:5, Informative)
They're not saying that infra-radiation is sound--they used the telescope to see ripples in the gas. That's the sound.
Re:This would be a "RTFA". It *is* sound. (Score:3, Interesting)
Wow - and I thought Germany had a long concert (Score:5, Interesting)
So this is a 639 year concert that has started in Germany. The concert has been ongoing for 17 months (the initial "quiet period" of the organ filling) however the first three note chord has been hit.
Boy wish I had that kind of time to waste... Imagine the monks 630 years from now going - "Well, this is over now - what the hell are we going to do now ?"
Re:Wow - and I thought Germany had a long concert (Score:3, Funny)
Re:Wow - and I thought Germany had a long concert (Score:1, Funny)
Bass solo.
Re:Wow - and I thought Germany had a long concert (Score:2)
Re:Wow - and I thought Germany had a long concert (Score:2)
But... but... (Score:2)
GSS (Score:5, Funny)
AKA "a giant sucking sound."
B-Flat 57 octaves below middle-C? (Score:3, Funny)
B-Flat 57 octaves below middle-C, and it's the sound of a black hole. My , they've discovered the brown note!
Umm, sorry for that...
No matter. (Score:5, Funny)
Re:No matter. (Score:2, Funny)
Make that replace his whole Star system.
Re:It is not sound (Score:2)
sound ( P ) Pronunciation Key (sound)
b.) Transmitted vibrations of any frequency.
Re:It is not sound (Score:2)
Re:It is not sound (Score:1)
So? My body's motion in such a case is sound. It may be inaudible. If you managed to shake me stongly and quickly enough, it would be audible to the human ear
Viewed as a particle, a photon does not vibrate. Viewed as a wave, a photon is a vibration, but of EM potential, not of
So... (Score:2)
I suppose it fillows that there is no such thing as ultrasound and the images I have of my daughter in utero were fradulent.
Sound is periodic vibrations due to compression waves in a medium. Within a certain range of frequencies, sound can be heard (if it is loud enough) outside of those frequencies, we still call it sound even if no one can hear it. That's what we're talking about
Re:It is not sound (Score:1)
Granted, I don't think anybody could hear that noise... but who knows, maybe some alien is bitching to his neighborhood association because that black hole won't turn it down or something.
B-Flat? (Score:1)
Re:B-Flat? (Score:1)
Yeah, I know (you?) musicological types like to talk about B sharp or F flat or whatever, but I've never understood why.
Re:B-Sharp? (Score:2)
Re:B-Flat? (Score:2)
The "fifth" of a note is supposed to be exactly 1.5 times the frequency. But, on a keyboard, the actual note is 2^(7/12) = 1.4983 times the frequency of the fundamental. If you tune an instrument so the 2^(1/12) relationship holds, that's equal temperament.
Re:B-Flat? (Score:1)
Alien (Score:2, Funny)
lol, your calculations? naughty! (Score:1)
Re:lol, your calculations? naughty! (Score:2)
Re:lol, your calculations? naughty! (Score:1)
Seems like a simple enough calculation to me.
from: http://hypertextbook.com/facts/2003/DanielleDaly.
Re:lol, your calculations? naughty! (Score:2)
Concert (Score:5, Funny)
Re:Concert (Score:4, Funny)
Re:Concert (Score:2)
"Sounds of Silence", for the infra-sound hearing impaired ?
Satchmo has found his soul home. (Score:1)
Satchmo has found his soul home (Score:1)
But does a brown dwarf... (Score:1)
play the "brown note" ?
On the team (Score:3, Interesting)
Re:On the team (Score:4, Funny)
Would you like some toast?
-Talkie Toaster
Re:On the team (Score:4, Funny)
Or muffins! Or muffins! We don't like muffins around here! We want no muffins, no toast, no teacakes, no buns, baps, baguettes or bagels, no croissants, no crumpets, no pancakes, no potato cakes and no hot-cross buns and definitely no smegging flapjacks!
Re:On the team (Score:1)
Re:On the team (Score:1)
Re:On the team (Score:2)
Re:On the team (Score:3, Informative)
Re:On the team (Score:2)
Re:On the team (Score:2)
Roughly, the speed is so fast as the gas is hot. The particles move much faster and so they propagate any pressure fluctations faster.
Re:On the team (Score:1)
Frequency (Score:2)
Do black holes exist? (Score:3, Interesting)
Black holes rely on an assumption that gravity has no limits on its strength, and to some extent on it following a strict Newtonian curve.
Thinking of "curves" in space-time is an interesting analogy for gravity, but still doesn't address the mechanism - sure, the planet may be on a "45 degree" incline in spacetime, but what forces it down... and not up? You would nearly have to posit the existence of some constant stream of gravitons coming at 'right angles' to three-dimensional space in order to actually push things 'down the well'.
There are alternate corpuscular (i.e. caused by particles; "quantum") models of the mechanism of gravity. There's the LeSagian model [wikipedia.org], with modern reworks that range from the bizarre-yet-possible theories of Tom Van Flandern, to the more "moderate" theories of Paul Stowe explaining how the "drag" factor that detractors expect doesn't show up, in exactly the sort of way that Feynman expressed it for electromagnetism.
The LeSage-type theories are, in general, "push" theories, which operate in a medium filled with gravitons (just as space is filled with photons) that are deflected/absorbed near bodies and cast 'shadows' that create a low "pressure" area close to surfaces and, to a lesser extent, between bodies.
The formulae calculate out approximately to Newton's/GR's gravity equation, but with some interesting exceptions:
This upper limit on the strength of gravity may prevent the ultimate collapse that black hole theory requires.
Black holes are still a theoretical construct. Even the jets [nasa.gov], now often taken as a 'sign' of a black hole, are still a largely unexplained phenomenon, one that is also associated with accretion disks for newly-forming stars.
So if something's singing in that cloud, it may not be as dense as it's accused of being.
I apologize for all the jargon. I shall go read another thread on SCO as just punishment :)
Re:Do black holes exist? (Score:4, Informative)
The best explantion for this I've ever heard deals entirely with special relativity and never touches quantum mechanics. The author I read (Epstein) discusses what he calls 'Slow Time'. An object is always moving in four dimenions, even if it appears at rest to an observer, because it is moving forward in time as well. Since all dimensions of space and time are warped by the presence of matter, and not just space, if the object being observed is closer to a source of gravity (on a steeper part of the curve of space-time), he will start to experience time shortening or time dialation sooner and more strongly than you, the observer. His straight-line path through time starts to curve toward the source of gravity. This time-dialation acts as a vector force to 'push' him towards the source of gravity.
You can read more about the interperatation of Special Relativity in this book: Relativity Visualized [amazon.com]
Re:Do black holes exist? (Score:3, Interesting)
See also:
"Study of the anomalous acceleration of Pioneer 10 and 11", Anderson, J.D., Laing, P.A., Lau, E.L., Liu, A.S., Nieto, M.M., and Turyshev, S.G., Physics Review D, v65, 082004, (2002)
Re:Do black holes exist? (Score:1)
The attenuation of gravity, according to one of the papers I ran across is about a kiloparsec, or about 3,300 light years from each single source.
It can help get around the apparent contradiction that intact spiral galaxies present.
Regardless, the attenuation is one of the predictions of one of the theories, and can be used to prove or disprove it. Currently, very little resources are being expended on such observations. Even Majorana's careful gravity shielding experiments have not yet been redone.
Ot
Re:Do black holes exist? (Score:1)
Thinking of "curves" in space-time is an interesting analogy for gravity, but still doesn't address the mechanism - sure, the planet may be on a "45 degree" incline in spacetime, but what forces it down... and not up?
That is the wrong question. Curvature is an intrinsic property of any spacetime; unless you are standing on something, there is no notion of down, up, or 45 degree incline. These notions arise only when using simplified "rubber-sheet" analogies to describe the effect of mass on the geomet
A force, or merely curved spacetime? (Score:1)
That's why I think the term "gravity well" is
Brown Note (Score:1)
Energy and sound (Score:2)
In a simplistic level, think of a stereo's tweeter speaker...short soundwaves that just hurt the ears if turned up too high. Then you've got the bass...longer soundwaves that you can feel the "punch". So I wonder what these soundwaves from the black holes are capable of doing. They've got to have some
Re:Energy and sound (Score:2)
We expect the actual sound amplitude to be similar to that produced by a human voice!
Re:Energy and sound (Score:2)
You need massive amounts of energy to heat the centre of a cluster and stop it cooling (an estimate is 10^36 erg/s).
Whoops! (Score:2)
Re:Energy and sound (Score:2)
Chandra images (Score:1)
http://chandra.harvard.edu/photo/chronological.ht
More pictures (Score:1)
Emotions (Score:1)
B Flat (Score:1, Funny)
Understatement? . . . . (Score:1)
The sound of a black Tupac dying (Score:1)