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Thread: What's the use for black holes?

  1. #1 What's the use for black holes? 
    Forum Professor Zwolver's Avatar
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    As i keep looking at these monsters, i can't help but wonder, what their part is in the circle of life. Where do they fit in. Why are there black holes, and what do they do? Like the sun is a giant fusion generator, creating bigger atoms, and slinging huge amount of energy into space. Are black holes the opposite? Breaking down energy to make matter, by absorbing huge amounts of energy and matter? Then where does it all go, or is it lost due to the huge gravity?

    Do they drive (in some way) the accellerating expansion of the universe, if it's even expanding to begin with. As what if space, or distance is just a mirage, and it's actually all on the tip of a pinn, but on perspective to other dimensions.

    Hmm, any idea's, as i like to philosophise now and then, but ive reached a black hole, literally.


    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  3. #2  
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    Black holes serve no purpose. They are just the end stage of massive stars, or in the result of supermassive ones, the result of a lot of matter coming together. As to why there are black holes, they are just what happen when enough matter is fit into a small enough volume. They are not part of any "circle of life", nor does does the term have any meaning when it comes to the universe as a whole.


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    How can they not have a function? Couldn't it simply be that it has a function, we just don't understand it yet? Something like dark energy/matter?
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  5. #4  
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    Quote Originally Posted by Zwolver View Post
    How can they not have a function?
    Why should they have a function? It is not like the universe is some gigantic clockwork machine.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Quote Originally Posted by Zwolver View Post
    How can they not have a function? Couldn't it simply be that it has a function, we just don't understand it yet? Something like dark energy/matter?
    I really don't know what you mean by purpose. Are you presupposing the universe itself has some sort of "purpose"?
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    Quote Originally Posted by Zwolver View Post
    How can they not have a function? Couldn't it simply be that it has a function, we just don't understand it yet? Something like dark energy/matter?
    There is no function, as in meaning "deliberately put there to achieve some purpose".
    Black holes do form a large part of the overall entropy of the universe though, and their evaporation via Hawking radiation thus increases the total entropy, thereby preserving the second law of thermodynamics. In a way large black holes are like machines which convert matter into radiation, over very long periods of time.
    This is a chicken-and-egg situation though - black holes evaporate in accordance with the second law of thermodynamics, and the second law holds because black holes evaporate. Which one is first to drive the other ? That's a question for philosophy to answer.
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    What is the function of the planet Mercury?

    What is the function of the Aurora Borealis?

    What is the function of a Gamma Ray Burst?

    What is the function of an asteroid?

    Why should everything need a function or purpose?
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  9. #8  
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    Perhaps one might say that black holes are a result of the function of gravity.
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  10. #9  
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    Quote Originally Posted by SpeedFreek View Post
    What is the function of the planet Mercury?

    What is the function of the Aurora Borealis?

    What is the function of a Gamma Ray Burst?

    What is the function of an asteroid?

    Why should everything need a function or purpose?
    Not everything has a function. But at a cosmic scale, mercury has a function of storing iron, and other compounds, as matter. I saw a black hole indeed as a clockwork, ticking back to the next big bang after the universe's atoms decayed to pure energy and the black holes have some part in igniting, maybe a mirrored version of last big bang into it. Mercury is just fuel, same as asteroids, gamma ray bursts are an excitation of energy that needed to be expelled from an atom, and aurora borealis exists because of the ionisation of the air gives light a slight bend, to make visible colors. It can't have a function, as it does not have a fysical form, it's just a visual thing.

    This still is something that black holes stand out of, they must serve SOME purpose, other then being giant vacuums for all matter. Wouldn't they repell antimatter in that case? So they might create matter and antimatter by pulling energy in, making matter out if it, and repelling antimatter....

    Just speculating, as i think they must serve some cosmic goal..
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  11. #10  
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    Quote Originally Posted by Zwolver View Post
    they must serve SOME purpose
    Why?

    Why must anything have some purpose?
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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  12. #11  
    Forum Professor Zwolver's Avatar
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    As everything we understand does have a purpose, to understand things properly, you MUST know it's function in the universe.
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  13. #12  
    ***** Participant Write4U's Avatar
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by Zwolver View Post
    they must serve SOME purpose
    Why?

    Why must anything have some purpose?
    I agree, there is only Cause and Effect. We don't know what happens beyond the Event Horizon. There are theories, speculations, but no identifiable mathematical laws or physical causal purpose, yet.
    Last edited by Write4U; April 12th, 2012 at 05:30 AM.
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    From Wiki,
    One of the most well-known examples of an event horizon derives from general relativity's description of a black hole, a celestial object so massive that no nearby matter or radiation can escape its gravitational field. Often, this is described as the boundary within which the black hole's escape velocity is greater than the speed of light. However, a more accurate description is that within this horizon, all lightlike paths (paths that light could take) and hence all paths in the forward light cones of particles within the horizon, are warped so as to fall farther into the hole. Once a particle is inside the horizon, moving into the hole is as inevitable as moving forward in time, and can actually be thought of as equivalent to doing so, depending on the spacetime coordinate system used
    Event horizon - Wikipedia, the free encyclopedia
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    Quote Originally Posted by Zwolver View Post
    As everything we understand does have a purpose, to understand things properly, you MUST know it's function in the universe.
    You are inventing functions post hoc. For example, you say "mercury has a function of storing iron, and other compounds, as matter" but that is just a description of what it is. It is not a "function" or "purpose". That would imply that there is a reason that it is being stored in Mercury; in case it is needed later?

    If you want to make up a purpose for black holes then perhaps it is to provide work for astrophysicists.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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  16. #15  
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    Quote Originally Posted by Zwolver View Post
    This still is something that black holes stand out of, they must serve SOME purpose, other then being giant vacuums for all matter. Wouldn't they repell antimatter in that case? So they might create matter and antimatter by pulling energy in, making matter out if it, and repelling antimatter....
    They are not "giant vacuums for all matter" any more than any other object with the same mass would be.

    As far as we know, antimatter has the same gravitational properties as matter (this has yet to be confirmed by experiment but there are good reasons for assuming it must be the case) so the idea that black holes would expel antimatter doesn't work.

    Just speculating, as i think they must serve some cosmic goal..
    I see no reason to think there is any such cosmic goal.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    But a question occurred to me in relation to Zwolfer's question. Is it possible for a particle to become stretched so long that it loses its physical properties altogether and breaks apart into Planck quanta which might be able to escape "through the bottom" of a black hole as virtual (metaphysical) particles which no longer respond to gravity.
    I am deep in woo here, but if such a thing is possible, then we might have a form of cosmic recycling, which would answer Zwolfer's question.
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    The only known (well, proposed) mechanism for anything to escape from a black hole is Hawking radiation.

    For any realistic black hole the effective temperature of the Hawking radiation is well below the 3K CMB so it would absorb more energy than it radiates. That is if it wasn't absorbing masses of material from an accretion disk.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Quote Originally Posted by Strange View Post
    The only known (well, proposed) mechanism for anything to escape from a black hole is Hawking radiation.

    For any realistic black hole the effective temperature of the Hawking radiation is well below the 3K CMB so it would absorb more energy than it radiates. That is if it wasn't absorbing masses of material from an accretion disk.
    Thanks for the term Hawking radiation. Checked out Wiki on that and was pleased that my intuitive (simplistic) musing was not all that far from what is actually being discussed by learned fellows.

    Hawking used a black hole solution without a past region which forms at a finite time in the past. In that case, the source of all the outgoing photons can be identified–it is a microscopic point right at the moment that the black hole first formed.
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  20. #19  
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    Kind of what i meant with "dark energy" being formed, or something like that. I'm not that knowledgable about the whole cosmic conversion thing. But Write4U kinda made a point of matter being transformed, or slingshotted somewhere. To get back at mercury, i know it's not a good explanation for why it is there. But it doesn't seem to do something, not as a black hole seems to be doing.

    As i got stuck with some of the theories (nobody else seemed to know), i just thought i would just put it out there. Would it be similar to the theory where atoms simply get smaller, and when they reach a point of mass instability, they form pure energy. This could be used into an (close to) infinite energy reactor. Simply making time pass super fast for a few atoms, making them smaller, to a point of collapse, and then gaining pure energy from them. Could eiter a black hole be doing just that, stopping all movement, so making time infinitely fast, thus collapsing normal matter into pure energy?

    And again, stop me if i'm making nonsense, as i'm a biologist.
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  21. #20  
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    Quote Originally Posted by Zwolver View Post
    And again, stop me if i'm making nonsense.
    Stop!

    as i'm a biologist
    Ah, that explains it.

    They didn't do biology at our school for some reason, so it took me a long time to realise it really is a science!
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    Quote Originally Posted by Zwolver View Post
    And again, stop me if i'm making nonsense, as i'm a biologist.
    To help me understand why you are asking the question you are asking please answer this one. What is the purpose of a mole rat?
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    They're cute and cuddly, of course, just like puppies and kittens!
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    Quote Originally Posted by John Galt View Post
    Quote Originally Posted by Zwolver View Post
    And again, stop me if i'm making nonsense, as i'm a biologist.
    To help me understand why you are asking the question you are asking please answer this one. What is the purpose of a mole rat?
    Reproduction, survival, filling a hole in the food chain. At the end, it's the product of it's ancestors, and it's making it's offspring in his image. It has medical uses, like studies for hairlessness, or living without light, the effects of blindness, etc etc.. A mole rat has a million functions like this. At the end it is enevitable it existed, and even more so that at one time it will end.

    If you ask for the answer if it fills a purpose like the a star, supernova's, or even a foton. No it can not be compared to it in this way.

    Thanks for the ridicule of biologists anyway. And as far as i know, it is a science.. But what do i know, i'm just a biologist..
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  25. #24  
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    Zwolfer,
    I believe there may be some confusion from your use of the word "purpose".

    IMO, if you were to use the word "function", it probably would resolve the issue.

    From Webster's

    Definition of FUNCTION
    1: professional or official position : occupation
    2: the action for which a person or thing is specially fitted or used or for which a thing exists : purpose
    While function and purpose are closely related words, "purpose" has an implication of an intentionally created function. It hints at an intelligence. IMO, this may be the source of confusion.

    P.S. Ik ben ook een Hollander....
    Last edited by Write4U; April 13th, 2012 at 06:15 AM.
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  26. #25  
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    Quote Originally Posted by Zwolver View Post
    Thanks for the ridicule of biologists anyway. And as far as i know, it is a science.. But what do i know, i'm just a biologist..
    Hey, I wasn't intending to ridicule biologists. I was just making a joke about the fact that I didn't learn any biology until I left school (I think I used to confuse it with botany!). So, if anything, I was ridiculing my own ignorance.
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    Quote Originally Posted by Write4U View Post
    Zwolfer,
    I believe there may be some confusion from your use of the word "purpose".

    IMO, if you were to use the word "function", it probably would resolve the issue.

    From Webster's

    Definition of FUNCTION
    1: professional or official position : occupation
    2: the action for which a person or thing is specially fitted or used or for which a thing exists : purpose
    While function and purpose are closely related words, "purpose" has an implication of an intentionally created function. It hints at an intelligence. IMO, this may be the source of confusion.
    That may be part of the problem. I'm not sure that "function" is much better (because it implies purpose).

    In the end, all we can do is to describe what things do. The "why" part is not really science.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Quote Originally Posted by Zwolver View Post
    Reproduction, survival, filling a hole in the food chain. At the end, it's the product of it's ancestors, and it's making it's offspring in his image. It has medical uses, like studies for hairlessness, or living without light, the effects of blindness, etc etc.. A mole rat has a million functions like this..
    As Write4U says, these are all "functions" (things it does) they are not "purpose" (reason for it doing them).

    We can describe what a black hole does in the same way (curves spacetime, etc). There is no "reason", though.

    At the end it is enevitable it existed
    I would disagree with this. If you rewound the world to some time before the existence of mole rates, it isn't inevitable that they would evolve again. Something similar might. Something (or things) filling the same ecological niche almost certainly.
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  29. #28  
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    Quote Originally Posted by Write4U View Post
    Zwolfer,
    I believe there may be some confusion from your use of the word "purpose".
    Hmm, ok.. well, as i don't believe in creation (except our own), i didn't see any difference. But allright, no i didn't mean a black hole was created by any god to preform a function. But i thought there must be some proces going on in there to .. make matter, break matter off, doing something with energy, ticking back from the big bang, or ticking towards the next one...

    Go Dutch
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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  30. #29  
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    Quote Originally Posted by Strange View Post
    At the end it is enevitable it existed
    I would disagree with this. If you rewound the world to some time before the existence of mole rates, it isn't inevitable that they would evolve again. Something similar might. Something (or things) filling the same ecological niche almost certainly.
    Yes, even more peculiar, you would exist, not remembering yourself doing the things your doing now before, and the same questions would be asked and answered here again. The only thing that will be different, is the place of the energies that make up our atoms. Though they will fill the same locations, it will simply be different ones.

    That would not need to be the next big bang, but in a future everything will happen again (where strings will spin in exactly the same way as they are now).
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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    Write4U and Strange have captured my concerns about your use of the word purpose which certainly strongly implies an intention that the organism or thing should have a reason to exist other than circumstance.

    Does the following better express the intention of your OP?

    What significance do black holes have in the evolution of the universe? Do they play an important role that has far reaching consequences, or are they merely an interesting sideshow? If it is the former, what is the nature of this role and its impact?
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    I thought all we could know about black holes is their mass, charge, spin - and by implication the amount of entropy that a volume of space can hold which is indicated by the area of the black hole's event horizon? Also, that the last item indicates spacetime has some planck level atomic like property beyond which there is no finer substance?
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    Quote Originally Posted by ballyhoo View Post
    I thought all we could know about black holes is their mass, charge, spin - and by implication the amount of entropy that a volume of space can hold which is indicated by the area of the black hole's event horizon? Also, that the last item indicates spacetime has some planck level atomic like property beyond which there is no finer substance?
    If Hawking is correct, they also effectively have a temperature (i.e. Hawking radiation is black-body radiation corresponding to a body at that temperature).
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    Quote Originally Posted by ballyhoo View Post
    I thought all we could know about black holes is their mass, charge, spin - and by implication the amount of entropy that a volume of space can hold which is indicated by the area of the black hole's event horizon? Also, that the last item indicates spacetime has some planck level atomic like property beyond which there is no finer substance?
    Correct, however, this "no-hair theorem" actually refers to the solutions of the field equations of General Relatitivity which are used to describe a black hole, i.e. to the metric of the space-time in and around the black hole. These solutions have only three free parameters, being mass, charge and angular momentum, which uniquely determine the geometry of the space-time.
    The temperature and entropy of the black hole are a result of quantum effects, and are not subject to the no-hair conjecture.
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    Black holes are the only matter that can suspend light and the bind the universe around it.Knowing or better yet control could lead to far more advanced tech than we could ever understand.
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    Quote Originally Posted by bryan View Post
    Black holes are the only matter that can suspend light and the bind the universe around it.Knowing or better yet control could lead to far more advanced tech than we could ever understand.
    Black Holes don't 'suspend light' or 'bind the universe'. Control doesn't lead to advanced tech, advanced tech leads to control

    Is there a point to your post?
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    Gravitational Radiation, Luminous Black Holes, and Gamma-Ray Burst ... - Google Books Result

    books.google.com/books?isbn=0521849608...Maurice H. P. M. Van Putten - 2005 - Science - 308 pages
    ... independent of the GRB phenomenon, in light of our current estimates on the ... 14.5 Equations of suspended accretion The suspended accretion state of the ... and angular momentum flux, received from the black hole and radiated to infinity ...
    Read more then comment or school might be a better way.
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    Quote Originally Posted by bryan View Post
    Gravitational Radiation, Luminous Black Holes, and Gamma-Ray Burst ... - Google Books Result

    books.google.com/books?isbn=0521849608...Maurice H. P. M. Van Putten - 2005 - Science - 308 pages
    ... independent of the GRB phenomenon, in light of our current estimates on the ... 14.5 Equations of suspended accretion The suspended accretion state of the ... and angular momentum flux, received from the black hole and radiated to infinity ...
    That has nothing to do with 'suspending light' or 'binding the universe'. It appears to be about gravitational radiation.
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    So light can pass by a blackhole without alteration?
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    Quote Originally Posted by bryan View Post
    So light can pass by a blackhole without alteration?
    Its path will be curved if it passes near a black hole (or any mass, for that matter - black holes are not that special in that regard). This is what causes gravitational lensing.
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    The black hole causes more than just great gravitational pull.The universe could be in a black hole for all we know.
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    Quote Originally Posted by bryan View Post
    The black hole causes more than just great gravitational pull.
    What else does a black hole cause? A black hole can have mass, angular momentum and charge. What else are you suggesting?

    The universe could be in a black hole for all we know.
    I don't think so.
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    singularity multi-dimension we can not study the mass effects inside so who knows.
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    Time itself could be altered to where its suspended.
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    Be rite back need coffee
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by bryan View Post
    ... independent of the GRB phenomenon, in light of our current estimates on the ... 14.5 Equations of suspended accretion The suspended accretion state of the ... and angular momentum flux, received from the black hole and radiated to infinity ...
    That has nothing to do with 'suspending light' or 'binding the universe'. It appears to be about gravitational radiation.
    I like that hightlighted word "light".
    Unfortunately it belongs to a larger phrase "in light of our current estimates" and has nothing to do with photons.
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    Quote Originally Posted by bryan View Post
    singularity multi-dimension we can not study the mass effects inside so who knows.
    What?

    We have no reason to think that GR does not describe the interior of a black hole.

    Quote Originally Posted by bryan View Post
    Time itself could be altered to where its suspended.
    What??
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Well... bologna cakes
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    Quote Originally Posted by bryan View Post
    Be rite back need coffee
    You need more than coffee!
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    Quote Originally Posted by bryan View Post
    Time itself could be altered to where its suspended.
    "Due to staff shortages, we regret to announce that time has been suspended until further notice. The Management."

    But how will they know when to resume service ....
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Regarding the expansion issue - isn't it true that black holes twist space around them as they rotate? Wasn't that proven recently with some satellite experiments concerning GR? or SR? How far does this twisting happen? How does the space untwist near the black hole?
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    Quote Originally Posted by ballyhoo View Post
    Regarding the expansion issue - isn't it true that black holes twist space around them as they rotate? Wasn't that proven recently with some satellite experiments concerning GR? or SR? How far does this twisting happen? How does the space untwist near the black hole?
    Yes, this effect is called "frame dragging", and is present to a degree around all rotating masses ( even Earth ). This phenomenon would be especially pronounced in the vicinity of a very large mass rotating very fast, like a Kerr black hole :

    Kerr metric - Wikipedia, the free encyclopedia
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    so if it's proven by experiment about frame dragging and twisting space around a massive object - what about contracting space towards the massive object?
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    Quote Originally Posted by ballyhoo View Post
    so if it's proven by experiment about frame dragging and twisting space around a massive object - what about contracting space towards the massive object?
    "Contracting space" - I assume what you mean is "curved" space. Curvature in space-time manifests itself in a very simple, everyday phenomenon - gravity.
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    sorry, I can see how you would interpret my question that way - I meant a kind of continuous folding of space in an accordion like manner that the black hole might absorb as a sponge might absorb water in which it is immersed except continuously- a kind of removal of spacetime from our universe to the realm inside the event horizon. (or is that only possible in the sense that volume of the black hole grows as more matter and energy are added?)
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    Quote Originally Posted by ballyhoo View Post
    sorry, I can see how you would interpret my question that way - I meant a kind of continuous folding of space in an accordion like manner that the black hole might absorb as a sponge might absorb water in which it is immersed except continuously- a kind of removal of spacetime from our universe to the realm inside the event horizon. (or is that only possible in the sense that volume of the black hole grows as more matter and energy are added?)
    Imagine a rubber sheet stretched between your hands that you have drawn a grin on to. Now imagine putting a heavy weight on it. That is a 2D analogue to spacetime having curvature, i.e. gravity. With a black hole, all the grid lines crossing the event horizon never come out again, so that when you cross the event horizon, you can only ever move closer to the centre of mass. Those grid lines are analogous to geodesics, i.e. straight lines from the perspective of someone travelling on it. That means that a photon would follow a grid line without deviating as it crosses the event horizon, even though from its own perspective it is still travelling in a straight line.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    KALSTER,

    I think you meant grid, not grin, in the first sentence, but is a fun Freudian slip
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    Quote Originally Posted by MeteorWayne View Post
    KALSTER,

    I think you meant grid, not grin, in the first sentence, but is a fun Freudian slip
    Probably because he is used to working in smiles and not skilometres.
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    Haha, very punny! :-D
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

    "Gullibility kills" - Carl Sagan
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    Quote Originally Posted by ballyhoo View Post
    sorry, I can see how you would interpret my question that way - I meant a kind of continuous folding of space in an accordion like manner that the black hole might absorb as a sponge might absorb water in which it is immersed except continuously- a kind of removal of spacetime from our universe to the realm inside the event horizon. (or is that only possible in the sense that volume of the black hole grows as more matter and energy are added?)
    Space-time doesn't fold in an accordion-like manner; it only curves.
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    Quote Originally Posted by Markus Hanke View Post
    Space-time doesn't fold in an accordion-like manner; it only curves.
    so, no Music of the Spheres, then.
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    I have a couple of more serious questions (hopefully).

    If we have a 3 dimensional curvature of spacetime around and ending at a massive singularity, could the following be true,

    a) a completely circular spacetime curvature with a singularity at its center, somewhat like a doughnut with a tiny massive center?
    b) causing a seperate mini universe within the universe?
    c) when seperate mini universes of relatively equal mass collide, disturbing the spacetime curvature of each, could the result be a Big Bang of sorts?
    d) when two mini universes of unequal size collide, could there still be a disturbance of the spacetime curvature leading to the release(escape) of energy?
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    My post here is purely spekulative, so forgive me if it contradicts anything scientific.

    I do indeed think black holes serve a purpose.

    - contributing a bit to keeping the galaxy together.
    - recycle and redistribute matter.
    - help the rotation of the galaxy.

    OP you shouldn't be discouraged by all these negative answers, when it comes to unqualifyed guesswork even scientists fail so hard at it.
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by ballyhoo View Post
    sorry, I can see how you would interpret my question that way - I meant a kind of continuous folding of space in an accordion like manner that the black hole might absorb as a sponge might absorb water in which it is immersed except continuously- a kind of removal of spacetime from our universe to the realm inside the event horizon. (or is that only possible in the sense that volume of the black hole grows as more matter and energy are added?)
    Space-time doesn't fold in an accordion-like manner; it only curves.
    In one of my musing I visualized the unfolding of spacetime like a rolled up round carpet. When you drop a carpet it instantly creates a flat dimension and begins to unfurl, slowly at first but with increasing speed until the entire carpet is flat, but as it is made of strings, the final carpet consists of a stringy cosmic foam.

    Another domestic fantasy visualization is the doughnut shaped universe. Actually it is a very elegant design.
    Spacetime starts out from the center (white hole, BB), expands as it travels in all directions outwards toward the horizon, and passing the horizon where it begins to contract and eventually returns back to the center (black hole, BI (implosion) at the opposite side, if it still existed. But creating a nice fluffy (foamlike) outershell.
    It would allow for all the universes Hawking spoke of, some with black holes where information is retained, some without black holes where information is lost.

    I thought to bring a touch of levity in this subject of such gravity...
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    Quote Originally Posted by Write4U View Post
    I have a couple of more serious questions (hopefully).

    If we have a 3 dimensional curvature of spacetime around and ending at a massive singularity, could the following be true,

    a) a completely circular spacetime curvature with a singularity at its center, somewhat like a doughnut with a tiny massive center?
    b) causing a seperate mini universe within the universe?
    c) when seperate mini universes of relatively equal mass collide, disturbing the spacetime curvature of each, could the result be a Big Bang of sorts?
    d) when two mini universes of unequal size collide, could there still be a disturbance of the spacetime curvature leading to the release(escape) of energy?
    a) Such a construct would be closed in itself, and not causally connected to our universe, so it wouldn't be observable, and it wouldn't have a center point either (more of a bubble than a torus). If it's possible or not - I don't know, some serious maths would have to be done to determine that.

    b) Like I said, it would be somewhat like a closed "bubble" of spacetime, not causally connected to our universe. Not sure if you could call such a bubble a "universe" in its own right.

    c) No, such bubbles wouldn't interact with each other, or with our universe.

    d) See (c) above
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    Quote Originally Posted by HexHammer View Post
    My post here is purely spekulative, so forgive me if it contradicts anything scientific.
    OK, you're forgiven for posting something completely unscientific
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by ballyhoo View Post
    sorry, I can see how you would interpret my question that way - I meant a kind of continuous folding of space in an accordion like manner that the black hole might absorb as a sponge might absorb water in which it is immersed except continuously- a kind of removal of spacetime from our universe to the realm inside the event horizon. (or is that only possible in the sense that volume of the black hole grows as more matter and energy are added?)
    Space-time doesn't fold in an accordion-like manner; it only curves.
    Well, I just wondered because if you can twist spacetime then why not absorb it like a sponge?
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    Quote Originally Posted by HexHammer View Post
    My post here is purely spekulative, so forgive me if it contradicts anything scientific. I do indeed think black holes serve a purpose. - contributing a bit to keeping the galaxy together. - recycle and redistribute matter. - help the rotation of the galaxy. OP you shouldn't be discouraged by all these negative answers, when it comes to unqualifyed guesswork even scientists fail so hard at it.
    I think your first and third idea are interesting but it seems that physicists think that black hole only evaporate matter as radiation only across a very long time? So your second idea seems unlikely.
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    Quote Originally Posted by MeteorWayne View Post
    Quote Originally Posted by HexHammer View Post
    My post here is purely spekulative, so forgive me if it contradicts anything scientific.
    OK, you're forgiven for posting something completely unscientific
    why unscientific? They are hypothesis I grant you, but they don't seem like pure fantasy.
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    Quote Originally Posted by ballyhoo View Post
    I think your first and third idea are interesting but it seems that physicists think that black hole only evaporate matter as radiation only across a very long time? So your second idea seems unlikely.
    When bh's are very young they will usually "feed" and spew out matter in a jetstream at both poles, thus "redistributing matter". Also when they die and disperse they will eventually spread it's matter.
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    Quote Originally Posted by HexHammer View Post
    Quote Originally Posted by ballyhoo View Post
    I think your first and third idea are interesting but it seems that physicists think that black hole only evaporate matter as radiation only across a very long time? So your second idea seems unlikely.
    When bh's are very young they will usually "feed" and spew out matter in a jetstream at both poles, thus "redistributing matter". Also when they die and disperse they will eventually spread it's matter.
    What's your source for this claim? I have never heard of black holes dying and dispersing excepting through the theories of hawking as radiation.
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    Quote Originally Posted by ballyhoo View Post
    When bh's are very young they will usually "feed" and spew out matter in a jetstream at both poles, thus "redistributing matter". Also when they die and disperse they will eventually spread it's matter.
    What's your source for this claim? I have never heard of black holes dying and dispersing excepting through the theories of hawking as radiation.[/QUOTE]

    Quote Originally Posted by [url=http://simple.wikipedia.org/wiki/Black_hole
    Black hole - Simple English Wikipedia, the free encyclopedia[/url]]Black hole evaporationIt was commonly thought that a black hole was there forever and if you were trapped in one, you would be stuck there eternally. This was proved wrong when scientists discovered small leaks in black holes. This meant that over billions and billions of years, a black hole would disperse. The leaking is slow at first, but as it gets smaller, it gets faster and faster.
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    Quote Originally Posted by ballyhoo View Post
    Quote Originally Posted by MeteorWayne View Post
    Quote Originally Posted by HexHammer View Post
    My post here is purely spekulative, so forgive me if it contradicts anything scientific.
    OK, you're forgiven for posting something completely unscientific
    why unscientific? They are hypothesis I grant you, but they don't seem like pure fantasy.
    1) because my vocabulary is very limited, english isn't my first language, so I wouldn't know the correct term for what I have to say, so I had to cover myself in.

    2) I don't really have a clue about anything, most of my knowledge is from short faulty Wiki notes, and some docs on NG and DC.

    3) I've seen many people talk about millions more things that I ever know, thus my knowledge is therefore extremely limited and may be very faulty.
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    Quote Originally Posted by HexHammer View Post
    Quote Originally Posted by [url=http://simple.wikipedia.org/wiki/Black_hole
    Black hole - Simple English Wikipedia, the free encyclopedia[/url]]Black hole evaporation It was commonly thought that a black hole was there forever and if you were trapped in one, you would be stuck there eternally. This was proved wrong when scientists discovered small leaks in black holes. This meant that over billions and billions of years, a black hole would disperse. The leaking is slow at first, but as it gets smaller, it gets faster and faster.
    I appreciate that English is not your first language but ... I would be careful about information on Wikipedia. And even more careful about this simplified version.

    There is no way a realistic black hole will evaporate in the lifetime of the universe. Hawking radiation is "black body" radiation. This means it has an equivalent temperature associated with it. For any reasonable size black hole this temperature is a tiny fraction of a degree above absolute zero. So even an isolated black hole will gain more mass from the CMB than it loses from Hawking radiation. And, in practice, balck holes will gather even more from infalling material.
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    Is the passing of time, inside and outside of the black hole, the same?

    Can we use the energy output of a black hole for something (in theory)?
    Growing up, i marveled at star-trek's science, and ignored the perfect society. Now, i try to ignore their science, and marvel at the society.

    Imagine, being able to create matter out of thin air, and not coming up with using drones for boarding hostile ships. Or using drones to defend your own ship. Heck, using drones to block energy attacks, counterattack or for surveillance. Unless, of course, they are nano-machines in your blood, which is a billion times more complex..
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    Quote Originally Posted by Zwolver View Post
    Is the passing of time, inside and outside of the black hole, the same?
    They can't even be compared. Because an event horizon means that there is no causal connection between the inside of the event horizon and the rest of the universe there is no way of relating the two.

    Can we use the energy output of a black hole for something (in theory)?
    The energy output is approximately the same as a body at 0 kelvin. So probably not.
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    Quote Originally Posted by Strange View Post
    I appreciate that English is not your first language but ... I would be careful about information on Wikipedia. And even more careful about this simplified version.

    There is no way a realistic black hole will evaporate in the lifetime of the universe. Hawking radiation is "black body" radiation. This means it has an equivalent temperature associated with it. For any reasonable size black hole this temperature is a tiny fraction of a degree above absolute zero. So even an isolated black hole will gain more mass from the CMB than it loses from Hawking radiation. And, in practice, balck holes will gather even more from infalling material.
    Please allow me to specify and elaborate.
    This simplifyed wikiquite isn't where I first found this information, but on TV which in some eyes may be the same, as they only see admissible evidense from science scribbles from fancy learning institutions.

    It surprises me time and time again, how people can speak with such absolute certainty about theoretical matters.

    Each times the eggheads sends a prope to anywhere in our solar system they'r always proved wrong in most matters, that's even what we have a reasonable good ability to observe, black holes are not direct observeable therefore we should be even more careful about such absolute statements.

    In order for a BH to gain mass, there mut be nearby matter to feed on, if there are no nearby matter, it can't feed.
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    Quote Originally Posted by HexHammer View Post
    It surprises me time and time again, how people can speak with such absolute certainty about theoretical matters.
    I keep meaning to change my sig. line to something like "usual disclaimers and caveats apply".

    Also, in science, "theoretical" means the very best understanding we currently have confirmed by multiple lines of evidence. It doesn't mean (as it might in casual conversation) that it is just random speculation.

    Sure, Hawking may be wrong about Hawking radiation. It depends on his attempt to approximate the effects of general relativity and quantum theory in the neighbourhood of an event horizon. Not everybody thinks he has got it right. But no one has definitively shown him to be wrong.

    However, it is so far the only known mechanism for black holes to lose mass. If Hawking radiation doesn't exist then, as far as we know, black holes cannot lose mass. If Hawking radiation does exist then, as far as we know, black holes can only lose mass at a slower rate than they will gain it.

    This simplifyed wikiquite isn't where I first found this information, but on TV which in some eyes may be the same, as they only see admissible evidense from science scribbles from fancy learning institutions.
    Some documentaries are very good. Some not so much. But, the important thing to realise is they all present a simplified explanation by means of analogies. (They may also exaggerate to some extent for dramatic effect.) Those analogies will not be completely accurate (because they are analogies) and it is dangerous to extrapolate too far using them.

    It is, perhaps, more important to understand that these are analogies (whether that is "expanding space", "black hole", "spooky action at a distance", the "virtual pairs" explanation of Hawking radiation, or whatever) than it is to understand the full (inevitably mathematical) theory behind it.

    In order for a BH to gain mass, there mut be nearby matter to feed on, if there are no nearby matter, it can't feed.
    In the absence of matter, they will gain mass (very, very slowly) by absorbing the cosmic background radiation. And, except for very small black holes (which may not exist) they will do this faster than they lose mass through Hawking radiation.

    Disclaimer:
    All the above is based on my limited understanding of our current best theories which are, of course, provisional and subject to change.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
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    Quote Originally Posted by HexHammer View Post
    It surprises me time and time again, how people can speak with such absolute certainty about theoretical matters.
    In order for a BH to gain mass, there mut be nearby matter to feed on, if there are no nearby matter, it can't feed.
    It appears to me that you have just spoken with absolute certainty about a theoretical matter.
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    Strange,
    However, it is so far the only known mechanism for black holes to lose mass. If Hawking radiation doesn't exist then, as far as we know, black holes cannot lose mass. If Hawking radiation does exist then, as far as we know, black holes can only lose mass at a slower rate than they will gain it.
    Is that not something like having a "half life" in other radiant matter. As I understand it a BH is just a few degrees above absolutr zero, and its radiation is minimal compared to its mass.
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    what puzzles me is how we know the actual or probable temperature inside the event horizon. Isn't the temperature determined by the blackbody radiation or some other spectra? So if no radiation can escape the even horizon how do we know it's a singularity or an extremely compact ordered mass or an extremely compact chaotic (high temperature internally) mass? mathematics?
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    Quote Originally Posted by Write4U View Post
    Is that not something like having a "half life" in other radiant matter. As I understand it a BH is just a few degrees above absolutr zero, and its radiation is minimal compared to its mass.
    The temperature, and therefore the rate at which it radiates away energy, is inversely proportional to its mass; i.e. the smaller it is, the hotter it is and the sooner it will evaporate (at an increasing rate).

    A black hole with the mass of our sun would have a lifetime of about 1067 years (much longer than the current age of the universe) if it never gained any mass from outside.

    To be in thermal equilibrium with the CMB it would need to have a mass of less than 1% of the earth - it isn't clear that such small black holes can even exist.
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    Quote Originally Posted by ballyhoo View Post
    what puzzles me is how we know the actual or probable temperature inside the event horizon. Isn't the temperature determined by the blackbody radiation or some other spectra? So if no radiation can escape the even horizon how do we know it's a singularity or an extremely compact ordered mass or an extremely compact chaotic (high temperature internally) mass? mathematics?
    It is not the temperature inside the event horizon - as you rightly say, we cannot know anything about that. It is the (effective) temperature of the event horizon. Which then acts as a perfect black body.

    The temperature, and hence radiation, also depends on your distance and motion relative to the black hole. The calculations are done assuming an infinitely distant observer. Which is good enough for any reasonable distance away. But, for example, if you were in free fall towards a black hole, you would see no Hawking radiation.
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    Uranium can be cold, yet give off radiation. I understand they measure the temperature of the source by its "leaking" of radiation. Very low radiation means very low temperature. Very high radiation means high energy or pressure (heat).
    The most radiation in a black hole occurs "at" the event horizon, which rotates very fast and produces high heat from friction.
    The core (singularity) may consist of non-radiant matter or may be so dense or small as not to allow for any movement whatever and may be cold itself.
    I admit I am deep into woo here.

    edit: just read the above posts........
    Last edited by Write4U; April 23rd, 2012 at 03:35 PM.
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    Quote Originally Posted by Write4U View Post
    Uranium can be cold, yet give off radiation.
    That is a different thing. Nuclear radiation is independent of temperature.

    The most radiation in a black hole occurs "at" the event horizon, which rotates very fast and produces high heat from friction.
    Nooooooooo!

    Hawking radiation is dependent only on the mass, not the angular momentum. Also, the event horizon isn't a "thing" which can have experience friction (apart from the fact it is in a vacuum).

    I admit I am deep into woo here.
    You can say that again!
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by Write4U View Post
    Uranium can be cold, yet give off radiation.
    That is a different thing. Nuclear radiation is independent of temperature.

    The most radiation in a black hole occurs "at" the event horizon, which rotates very fast and produces high heat from friction.
    Nooooooooo!

    Hawking radiation is dependent only on the mass, not the angular momentum. Also, the event horizon isn't a "thing" which can have experience friction (apart from the fact it is in a vacuum).
    Strange,
    It is the (effective) temperature of the event horizon. Which then acts as a perfect black body.
    Is that not what I said? And how is this temperature achieved? And what type of radiation does it produce?

    I understand the Hawking radiation is generated by the singularity itself and is different than the radiation produced "of" ("at") the event horizon.

    I may have phrased it incorrectly, but meant the same thing as you posited.....
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    Quote Originally Posted by Write4U View Post
    Strange,
    It is the (effective) temperature of the event horizon. Which then acts as a perfect black body.
    Is that not what I said? And how is this temperature achieved? And what type of radiation does it produce?
    Well, you said it was produced by friction, which it definitely isn't. As to how it is achieved, hawking said that you could think of it in terms of virtual particles and anti-particles being formed at the event horizon with one going into the black hole and the other being radiated. This doesn't accurately describe what the math says and raises all sorts of conceptual problems. Unfortunately, I haven't seen another explanation that explains the math better. And I don't understand the math either! You need to have a really good understanding of the math of both general relativity and quantum mechanics...

    It is thermal radiation with a black body spectrum (which is why we can talk about an effective temperature at the event horizon - even though there isn't anything at the event horizon to have a temperature).

    I understand the Hawking radiation is generated by the singularity itself and is different than the radiation produced "of" ("at") the event horizon.
    No, Hawking radiation is generated at the event horizon. Nothing from inside the event horizon can get out (that is what "event horizon" means).
    Last edited by Strange; April 24th, 2012 at 03:18 AM. Reason: spelling
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by Write4U View Post
    Strange,
    It is the (effective) temperature of the event horizon. Which then acts as a perfect black body.
    Is that not what I said? And how is this temperature achieved? And what type of radiation does it produce?
    Well, you said it was produced by friction, which it definitely isn't. As to how it is achieved, hawking said that you could think of it in terms of virtual particles and anti-particles being formed at the event horizon with one going into the black hole and the other being radiated. This doesn't accurately describe what the math says and raises all sorts of conceptual problems. Unfortunately, I haven't seen another explanation that explains the math better. And I don't understand the math either! You need to have a really good understanding of the math of both general relativity and quantum mechanics...

    It is thermal radiation with a black body spectrum (which is why we can talk about an effective temperature at the even horizon - even though there isn't anything at the even horizon to have a temperature).

    I understand the Hawking radiation is generated by the singularity itself and is different than the radiation produced "of" ("at") the event horizon.
    No, Hawking radiation is generated at the event horizon. Nothing from inside the event horizon can get out (that is what "event horizon" means).
    OK, thought I had read it somewhere, but can not refrence it. Wiki does confirm to your explain.
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    Strange, I just have to say you have done a superb job in explaining (in mathematical layman's terms) a very complicated subject. Kudos!!
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    What are these virtual particles? Are they generated from the higgs field? Does one or the other always escape the region of the event or horizon or is it a random mixture?
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    Quote Originally Posted by ballyhoo View Post
    What are these virtual particles? Are they generated from the higgs field? Does one or the other always escape the region of the event or horizon or is it a random mixture?
    The wiki article seems like a fair introduction to me, but I am not an expert in this field by a long shot: Virtual particle - Wikipedia, the free encyclopedia

    And it's randon, only particles that form right at the event horizon can be close enough that one of the pair is inside and the other outside.
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    Quote Originally Posted by ballyhoo View Post
    What are these virtual particles? Are they generated from the higgs field? Does one or the other always escape the region of the event or horizon or is it a random mixture?
    Remember, this is an analogy which is not very accurate (even if it is Hawking's own).

    Space is always full of pairs of virtual particles which pop in and out of existence due to the Heisenberg uncertainty principle. The story is that near the event horizon, one of the pair can get pulled in to the black hole and the other escapes. Now, the energy need to "pull apart" a pair of virtual particles and make them "real" is exactly equal to the energy (i.e. mass) of the two particles. This energy comes from the gravitational field of the black hole. One particle falls back in and the other escapes, leaving a net loss of energy corresponding to one particle.

    Imagine the particles are always photons (why not) and they have a spread of energies corresponding to a black body spectrum.

    This raises even more questions than it answers. Unless you are prepared to just accept it as a simplified story.

    A better description would have to deal with the fact that energy is observer dependent and the observer at infinite distance and far in the future will get a different value for the energy of the vacuum near the event horizon than someone far in the past and from that ... magic happens ... and you get Hawking radiation. But that is about the limit of my understanding.
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    Quote Originally Posted by Strange View Post
    There is no way a realistic black hole will evaporate in the lifetime of the universe. Hawking radiation is "black body" radiation. This means it has an equivalent temperature associated with it. For any reasonable size black hole this temperature is a tiny fraction of a degree above absolute zero. So even an isolated black hole will gain more mass from the CMB than it loses from Hawking radiation. And, in practice, balck holes will gather even more from infalling material.
    So, isn't it that you are going back to what Einstein said about BHs? That they'r consisten and can't dissolve? ..well I'm the n00b here anyways.
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    Quote Originally Posted by HexHammer View Post
    So, isn't it that you are going back to what Einstein said about BHs? That they'r consisten and can't dissolve?
    If they are of any realistic size then they can only grow. Really small black holes (if they exist) will evaporate. Really tiny ones will explode.

    (Assuming Hawking is correct, etc.)
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by HexHammer View Post
    So, isn't it that you are going back to what Einstein said about BHs? That they'r consisten and can't dissolve?
    If they are of any realistic size then they can only grow. Really small black holes (if they exist) will evaporate. Really tiny ones will explode.

    (Assuming Hawking is correct, etc.)
    So yes, you agree with Einstein.
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    Quote Originally Posted by HexHammer View Post
    So yes, you agree with Einstein.
    Of course. Well, I would prefer to say that General Relativity appears to be valid. It's not about the man but about the science.

    The entire concept of black holes is based on General Relativity, which is largely unchanged since Einstein developed it. (Apart from some extensions such as Hawkings work and some specific solutions of the equations.)
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    Quote Originally Posted by HexHammer View Post
    So yes, you agree with Einstein.
    This suggests that you don't agree with Einstein. Yes, no?
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    They will grow if they are bog, because they will almost certainly be surrounded by matter, the infalling of which will easily outstrip Hawking Radiation. They will still far in the future evaporate all the way.
    Disclaimer: I do not declare myself to be an expert on ANY subject. If I state something as fact that is obviously wrong, please don't hesitate to correct me. I welcome such corrections in an attempt to be as truthful and accurate as possible.

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    Who got rid of my awesome joke? I must know my oppressors name!
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    Quote Originally Posted by John Galt View Post
    Quote Originally Posted by HexHammer View Post
    So yes, you agree with Einstein.
    This suggests that you don't agree with Einstein. Yes, no?
    What Kalster said:
    Quote Originally Posted by KALSTER View Post
    They will grow if they are bog, because they will almost certainly be surrounded by matter, the infalling of which will easily outstrip Hawking Radiation. They will still far in the future evaporate all the way.
    However, I'm not excatly qualifyed to agree or disagree on my scarse knowledge.
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    Quote Originally Posted by HexHammer View Post
    What Kalster said:
    Quote Originally Posted by KALSTER View Post
    They will grow if they are bog, because they will almost certainly be surrounded by matter, the infalling of which will easily outstrip Hawking Radiation. They will still far in the future evaporate all the way.
    Can't see anything to disagree with there.
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