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Madtowntripper
Sun-Beams out of Cucumbers



Registered: 03/06/03
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Binary Black Hole Mergers (Semi-Long)
#7491614 - 10/06/07 02:29 PM (16 years, 3 months ago) |
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I know there are a few people here who are pretty interested in Astronomy so I thought I'd tell you guys about a presentation I listened to yesterday. I'm lucky enough to go to a school where each department runs a pretty good lecture series every week. Yesterday, the Physics department had Scott Hughes from MIT (A leader in gravitational wave phsyics) in to talk about his NASA experiment with Kip Thorne to put a series of detectors in space in order to look for black holes orbiting each other and eventually merging, and studying the gravitational waves that are emitted by such events. Apparently the idea is that this detector will be able to pinpoint with extreme precision the location, mass, velocity, and spin of these black holes. He says that simulations show that the precision would be 1%, but he believes it would actually be 10x-3 less than that.
Basically, the idea is this. If you look at a map of the density of the universe (such as this one here. http://www.virgo.dur.ac.uk/new/index.php?subject=millennium If you can find the video, watch it. Its the most amazing thing I've found this month.), its clear that density in the universe is increasing. This is exactly what you would expect to see, as the main attractive force present is gravity, and gravity is always positive, never negative. This means that anything with a gravitational force will always attract things to it. It will never repel them. So the basic structure of the universe is always small -> big, with stars, galaxies and superclusters forming from the accretion of items of smaller masses. This makes sense.
However, the problem is that the some of these structures seem to be TOO dense. In particular, the black holes that are present in the center of each galaxy are waaaay too big to have been formed just from the influx of accreted material. We know that these black holes are "sucking up" matter from the stars that orbit them, and that they are present in the center of most galaxies, like our own. But how they got so big was a mystery.
The solution that this experiment is designed to detect is a theoretical black hole merger. It seems that the size of these black holes beings to make sense if you stop assuming tha the only way they can grow is by accretion of normal matter, such as stars and planets, and can find that the occasionally black holes may in fact be attracted to, and merge with other black holes. Such an event would be almost unimaginably violent, and would result in the creation of extremely large gravity waves that could be used to glean tons of information about the bodies involved.
On a side note, such a merger would also be a handy explanation for the quasars that we see emitted from these black holes. When a black hole sucks up some normal matter, some part of this matter is commmonly emitted as bursts of strong radiation, called quasars. The problem is, quasars that we see are too strong to be created from of the absorption of stars local to a black hole. But if two black holes were colliding, the respective galaxies orbiting around them would be handy food for the formation of these phenomenon.
So to measure these events, like I said, these guys are planning to launch a network of satellites to look for the graviational waves that would be emitted by a black hole merger. You need a space based detector because the the frequencies involved are in the tens of millihertz, and would be easily overwhelmed by noise on or even near the planet. The detectors themselves would the most sensitive measuring instruments ever created. They will consist of precisely measured test masses floating in a vacuum on 3 separate satellites. The positions of these masses would be measured by an optical laser, and the distances relative to each other measured. The idea is that any change in distance between these masses would be the result of a passing gravitational wave. These changes in distance will be measured up to 10nanometers, which is something like 1/100th of the wavelength of light. (!)
I guess the technology is still a bit of a problem, since they aren't talking about launching this thing until 2017. But I thought it was a great talk about a great experiment, and I thought I'd let you guys hear about it.
-------------------- After one comes, through contact with it's administrators, no longer to cherish greatly the law as a remedy in abuses, then the bottle becomes a sovereign means of direct action. If you cannot throw it at least you can always drink out of it. - Ernest Hemingway If it is life that you feel you are missing I can tell you where to find it. In the law courts, in business, in government. There is nothing occurring in the streets. Nothing but a dumbshow composed of the helpless and the impotent. -Cormac MacCarthy He who learns must suffer. And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God. - Aeschylus
Edited by Madtowntripper (10/06/07 02:31 PM)
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OddEye


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Re: Binary Black Hole Mergers (Semi-Long) [Re: Madtowntripper]
#7491807 - 10/06/07 03:33 PM (16 years, 3 months ago) |
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I really liked! Keep posting!
-------------------- I'm at the highest peak, still glad the meak is understandin' me Artillery, thoughts of killin' me is just a fantasy The man in me is ready for war, like Holyfield-Tyson IV
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SymmetryGroup8
It's about theFLOW!



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Re: Binary Black Hole Mergers (Semi-Long) [Re: OddEye]
#7492050 - 10/06/07 05:11 PM (16 years, 3 months ago) |
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cool!!!
Don't know much of the physics behind it but it's really cool!
-------------------- Be like water my friend!
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Acyl
cyanidepoisoning


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Re: Binary Black Hole Mergers (Semi-Long) [Re: Madtowntripper]
#7492212 - 10/06/07 05:56 PM (16 years, 3 months ago) |
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Testing for gravitational waves.. wow..
I was always amazed when hawking mentioned they were essentially just light waves in "a brief history of time" I think it was.
Can you explain to me how this radiation escapes the blackholes? I never quite understood that (I didnt finish the book )
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1 ,2
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Madtowntripper
Sun-Beams out of Cucumbers



Registered: 03/06/03
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Re: Binary Black Hole Mergers (Semi-Long) [Re: Acyl]
#7492367 - 10/06/07 07:19 PM (16 years, 3 months ago) |
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Quote:
Acyl said: Testing for gravitational waves.. wow..
I was always amazed when hawking mentioned they were essentially just light waves in "a brief history of time" I think it was.
Can you explain to me how this radiation escapes the blackholes? I never quite understood that (I didnt finish the book )
I'm not even close to a physicist, in fact, I hate physics. But I'll try to answer that. In my understanding, under the effect of the black holes gravity all the matter in the area is attracted to the black hole. As all of this gas and other material rushes towards the same spot, and since the black hole is spinning, it forms into a large disk surrounding the mass of the black hole. All of these particles heat up as they move around each other and begin to glow and vaporize.. This super-heated material is what is ejected, apparently due to some type of magnetic energy.
So its not material which is from the black hole, per se, since the gravity of the black hole is indeed inescapable. But rather its material from the disk of gas that surrounds and feeds the black hole, and apparently is blasted out to form the radio waves which are our methods of finding quasars today.
-------------------- After one comes, through contact with it's administrators, no longer to cherish greatly the law as a remedy in abuses, then the bottle becomes a sovereign means of direct action. If you cannot throw it at least you can always drink out of it. - Ernest Hemingway If it is life that you feel you are missing I can tell you where to find it. In the law courts, in business, in government. There is nothing occurring in the streets. Nothing but a dumbshow composed of the helpless and the impotent. -Cormac MacCarthy He who learns must suffer. And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God. - Aeschylus
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robbyberto
Water Boy


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Re: Binary Black Hole Mergers (Semi-Long) [Re: Madtowntripper]
#7492409 - 10/06/07 07:31 PM (16 years, 3 months ago) |
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Any kind of colliding object would be extremely rare though. I mean even when galaxies come to together it would be a stretch of luck if any stars actually collided even though each galaxy has millions of stars. Basically, it seems very unlikely for a merger of two black holes to happen in any region of the universe where we can detect it. Still interesting.
-------------------- “People say having kids is life changing, well that doesn’t necessarily mean a good thing, does it? I could take one of my legs off. That would change my life.” -Karl Pilkington
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Madtowntripper
Sun-Beams out of Cucumbers



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Re: Binary Black Hole Mergers (Semi-Long) [Re: robbyberto]
#7492451 - 10/06/07 07:43 PM (16 years, 3 months ago) |
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Hughes said last night that he and Kip Thorne think they should be able to observe more than 10 events PER YEAR...
-------------------- After one comes, through contact with it's administrators, no longer to cherish greatly the law as a remedy in abuses, then the bottle becomes a sovereign means of direct action. If you cannot throw it at least you can always drink out of it. - Ernest Hemingway If it is life that you feel you are missing I can tell you where to find it. In the law courts, in business, in government. There is nothing occurring in the streets. Nothing but a dumbshow composed of the helpless and the impotent. -Cormac MacCarthy He who learns must suffer. And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God. - Aeschylus
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robbyberto
Water Boy


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Re: Binary Black Hole Mergers (Semi-Long) [Re: Madtowntripper]
#7492614 - 10/06/07 08:42 PM (16 years, 3 months ago) |
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What do I know? Cool stuff.
-------------------- “People say having kids is life changing, well that doesn’t necessarily mean a good thing, does it? I could take one of my legs off. That would change my life.” -Karl Pilkington
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Madtowntripper
Sun-Beams out of Cucumbers



Registered: 03/06/03
Posts: 21,287
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Re: Binary Black Hole Mergers (Semi-Long) [Re: robbyberto]
#7492646 - 10/06/07 08:54 PM (16 years, 3 months ago) |
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Here's a link to a bunch of data about the mission.
http://www.lisa-science.org/intro/nutshell
-------------------- After one comes, through contact with it's administrators, no longer to cherish greatly the law as a remedy in abuses, then the bottle becomes a sovereign means of direct action. If you cannot throw it at least you can always drink out of it. - Ernest Hemingway If it is life that you feel you are missing I can tell you where to find it. In the law courts, in business, in government. There is nothing occurring in the streets. Nothing but a dumbshow composed of the helpless and the impotent. -Cormac MacCarthy He who learns must suffer. And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God. - Aeschylus
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