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  4. Energy problem? What energy problem?
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Energy problem? What energy problem?

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Offline Batroost

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    « Reply #20 on: 25/06/2007 19:47:38 »
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    You have your physics all wrong. If you were to shoot individual particles into a black hole they would vanish without a trace.

    Bremsstrahlung?
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    Offline Soul Surfer

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    « Reply #21 on: 26/06/2007 00:02:46 »
    Bremsstrahlung  implies the presence of other material if there is a vacuum around the hole and you sling particles there a few at a time nothing much happens.  you have to have a lot of material rubbing against each other and trying to loose angular momentum to get into the hole to get any significant output
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    Offline syhprum

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    « Reply #22 on: 26/06/2007 10:28:13 »
    Although I agree that multiple collisions between particles rotating around a black hole will produce heating and consequent radiation this is not what I understand as Bremsstrahlung radiation.
    Surely this is radiation produced when particles move thru a medium at a greater speed than the speed of light in that medium ( a sort of sound barrier breaking type phenomena ).
     
    « Last Edit: 29/06/2007 11:33:29 by syhprum »
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    edward2007

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    « Reply #23 on: 26/06/2007 11:17:01 »
    <You have your physics all wrong.>
    Granted, but I am a writer, not a physisist. I have to go by the info you boffins publish, like:

    http://3quarksdaily.blogs.com/3quarksdaily/2005/04/physicists_coul.html

    http://cerncourier.com/cws/article/cern/29199

    So, if I misinterpreted it, maybe it was not clearly enough explained for the layman?

    <If you were to shoot individual particles into a black hole they would vanish without a trace.>
    Oh, and those pics that show giant jets of gas being expelled then?
    http://www.space.com/scienceastronomy/astronomy/our_black_hole_000920.html (scroll down a bit)

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    Offline Batroost

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    « Reply #24 on: 26/06/2007 20:06:54 »
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    Although I agree that multiple collisions between particles rotating around a black hole will produce heating and consequent radiation this is not what I understand as Bremsstrahlung radiation.
    Surely this is radiation produced when particles move thru a medium at a greater speed than the speed of light in that medium ( a sort of sound breaking breaking type phenomena ).

    No - that's Cerenkov radiation.
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    Offline ukmicky

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    « Reply #25 on: 26/06/2007 23:16:08 »
    Quote from: edward2007 on 26/06/2007 11:17:01
    <You have your physics all wrong.>
    Granted, but I am a writer, not a physicist. I have to go by the info you boffins publish, like:

    http://3quarksdaily.blogs.com/3quarksdaily/2005/04/physicists_coul.html

    http://cerncourier.com/cws/article/cern/29199

    So, if I misinterpreted it, maybe it was not clearly enough explained for the layman?

    <If you were to shoot individual particles into a black hole they would vanish without a trace.>
    Oh, and those pics that show giant jets of gas being expelled then?
    http://www.space.com/scienceastronomy/astronomy/our_black_hole_000920.html (scroll down a bit)

    That's a quasar.

    A quasar appears when a supermassive blackhole at the centre of a galaxy starts to consume something large like a star and the energy/light we view doesnt  actually come from inside the blackhole but rather spirals out from the spinning accretion disk which surrounds a black hole.

    When a black hole captures something like star in its gravity it doesn't get pulled straight in ,instead the star get broken up and ends up in an accretion disk around a blackhole.
    The Gas,dust etc end up in a sort of orbit circling the blackhole  and as it goes round the gas dust gets very hot due to friction which releases massive amounts of energy (x rays etc) all that energy and heat turns gas into plasma which then escapes the clutches of the blackhole.  We view the escape act as a quasar.


    Disclaimer    I think thats about right. :)
    « Last Edit: 26/06/2007 23:19:01 by ukmicky »
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    Offline Soul Surfer

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    « Reply #26 on: 27/06/2007 09:53:03 »
    In general you would get lots of material falling into a largeish black hole at once.  It would then form in an accretion disk and radiate loads of energy.  The original description suggested shooting one particle at a time into the hole which is very different.
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    « Reply #27 on: 27/06/2007 10:02:17 »
    An interesting thought though.  If it was a charged particle like an alpha particle (like you suggest)it would radiate synchrotron radiation as it orbited and lost energy(assuming that you could not aim it exactly at the hole when it would go straight in with hardly a squeak)  neutral atoms would not do this unless the black hole was so small that the tidal forces close to the event horizon disrupted the atoms.  I am not sure how small a black hole has to be before the tidal forces near the event horizon strip electrons from typical atoms.  probably ptretty small.
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    « Reply #28 on: 27/06/2007 10:21:03 »
    Just caught up with the articles you quote.  The small black holes they are talking about creating are extremely small, around the plank mass and have very short lives.  OK they will tell us lots more about what goes on at that sacale but are nowhere near the holes with the mass of a mountain that you need for significant energy production.  Remember the conservation of energy still applies you don't get something for nothing.  To "build" an energy production black hole  you need to put in more energy than you would ever get out of it! even if some of this is in the form of the mass of material you are using. 

    The smallest holes that you can genrate by using mass itself are formed when large stars with more than ten times the mass of the sun collapse to form black holes of a few solar masses.  Any smaller than this and you need to push the matrial together with quite some force or go back to conditions that prevailed in the early stages of the big bang.  so it is quite possible that there are a quite a few small mountain to planet mass black holes around in the universe but they are fantastically difficult to detect although if one was in orbit around a star it is in theory possible to detect it by the disturbance of the motion of the star to determine its mass and orbit and an unusual transit effect different from a normal planet as it pases infront of the star.
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