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Thread: Black holes

  1. #1 Black holes 
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    Does black holes tear the space-time fabric or just make a dimple in it?


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  3. #2  
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    If you wish to follow Einstein on Gravity, Black Holes make a dent in the space fabric, according to the mass of the BH. Since some are THOUGHT to be equal to millions or more of our solar mass, that can be a very deep dent.


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  4. #3 Re: Black holes 
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    Quote Originally Posted by Robins Thomas John
    Does black holes tear the space-time fabric or just make a dimple in it?
    spacetime is not a fabric, and it cannot be torn. That is just a terrible analogy found in the popular literature.

    A black hole is a region in space time that is created by extreme curvature (this is your "dimple") and from which nothing, including light, can escape. Associated with a balck hole is a closed surface called an event horizon. Nothing can move from the inside of the event horizon to the outside. Nothing is "torn" at that horizon.

    Inside the event horizon, things are a bit more complicated. General relativity predicts that space-time within the horizon is singular. That may be either an indication that quantum mechanics becomes important or that general relativity needs to be extended. Nobody knows the answer to this question.
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  5. #4 Re: Black holes 
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    Quote Originally Posted by DrRocket
    Quote Originally Posted by Robins Thomas John
    Does black holes tear the space-time fabric or just make a dimple in it?
    General relativity predicts that space-time within the horizon is singular. That may be either an indication that quantum mechanics becomes important or that general relativity needs to be extended. Nobody knows the answer to this question.
    I know the answer. GR needs to be modified. Let's say your first claim is true, that QM becomes important. Still, this means GR alone does not work, and needs to be modified.

    Answer is clear. The inside of a BH is a false idea.
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  6. #5 Re: Black holes 
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    Quote Originally Posted by Sanford
    Quote Originally Posted by DrRocket
    Quote Originally Posted by Robins Thomas John
    Does black holes tear the space-time fabric or just make a dimple in it?
    General relativity predicts that space-time within the horizon is singular. That may be either an indication that quantum mechanics becomes important or that general relativity needs to be extended. Nobody knows the answer to this question.
    I know the answer. GR needs to be modified. Let's say your first claim is true, that QM becomes important. Still, this means GR alone does not work, and needs to be modified.

    Answer is clear. The inside of a BH is a false idea.
    That is absolutely wrong. Absolute rubbish. You don't know any answers at all and lack the foundations in fundamental physics to have an informed opinion.

    You have proved here and elsewhere that you do not understand the basis for general relativity and are not prepared either in terms of mathematics or physics to understand it.

    Please confine your crank ideas to the Pseudoscience or New Hypothesis forumss here they belong.
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  7. #6 Re: Black holes 
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    Quote Originally Posted by Sanford
    I know the answer. GR needs to be modified. Let's say your first claim is true, that QM becomes important. Still, this means GR alone does not work, and needs to be modified.

    Answer is clear. The inside of a BH is a false idea.
    No, sir. That's what is known as a non-sequitur. We know GR does not apply in all contexts. We know it is limited in certain arenas. We know that QM brings a lot to the table, but we don't yet fully know how it applies at larger scales where GR excels.

    How you jump from that to, "The inside of a black hole is a false idea" is truly beyond me. I'm just gonna go out on a limb here... You've never studied formal logic nor anything to do with black hole cosmology or relativistic physics, is that correct?
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  8. #7 Re: Black holes 
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    Quote Originally Posted by inow
    Quote Originally Posted by Sanford
    I know the answer. GR needs to be modified. Let's say your first claim is true, that QM becomes important. Still, this means GR alone does not work, and needs to be modified.

    Answer is clear. The inside of a BH is a false idea.
    No, sir. That's what is known as a non-sequitur. We know GR does not apply in all contexts. We know it is limited in certain arenas. We know that QM brings a lot to the table, but we don't yet fully know how it applies at larger scales where GR excels.

    How you jump from that to, "The inside of a black hole is a false idea" is truly beyond me. I'm just gonna go out on a limb here... You've never studied formal logic nor anything to do with black hole cosmology or relativistic physics, is that correct?
    No. You should take a look at the thread "stress energy tensor" where Sanford demonstrates that he has attempted to read a very good book on the subject of general relativity and succeeded only in misconstruing the very basics. He has actually managed to acquire negative knowledge of the subject -- what he "knows" is wrong.

    What we are dealing with here is a full-fledged member of the "Einstein got it completely wrong" lunatic fringe.
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  9. #8 Re: Black holes 
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    Quote Originally Posted by Robins Thomas John
    Does black holes tear the space-time fabric or just make a dimple in it?
    It reverse it
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  10. #9 Published papers 
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    It is easy to criticize. It is hard to read. Can you guys read? I gave you a list of papers, and am waiting for comments on the papers. Is this the way you act in class, not reading what the prof assigned?
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  11. #10 Re: Black holes 
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    Quote Originally Posted by DrRocket
    Quote Originally Posted by inow
    Quote Originally Posted by Sanford
    I know the answer. GR needs to be modified. Let's say your first claim is true, that QM becomes important. Still, this means GR alone does not work, and needs to be modified.

    Answer is clear. The inside of a BH is a false idea.
    No, sir. That's what is known as a non-sequitur. We know GR does not apply in all contexts. We know it is limited in certain arenas. We know that QM brings a lot to the table, but we don't yet fully know how it applies at larger scales where GR excels.

    How you jump from that to, "The inside of a black hole is a false idea" is truly beyond me. I'm just gonna go out on a limb here... You've never studied formal logic nor anything to do with black hole cosmology or relativistic physics, is that correct?
    No. You should take a look at the thread "stress energy tensor" where Sanford demonstrates that he has attempted to read a very good book on the subject of general relativity and succeeded only in misconstruing the very basics. He has actually managed to acquire negative knowledge of the subject -- what he "knows" is wrong.

    What we are dealing with here is a full-fledged member of the "Einstein got it completely wrong" lunatic fringe.
    I resent name calling! I resent being called a lunatic! People like you should be banned!

    I asked a few questions that no one answered. E.g., I asked for a thought experiment to verify the nonlinearity assumption. The question is that since it is logically possible to get another theory that gives the correct observations such as bending of light, we need direct confirmation of the assumptions.

    You said my physics is wrong. Wrong means that the mathematics is not consistent. Did I present an inconsistent mathematics? No. Then I am not wrong. Is the standard explanations of GR mathematically consistent? I am not sure. We need to clarify this, but not talk like politicians.
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  12. #11  
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    i am aware that uniting gravity with quantum mechanics has not been a viable feat yet.

    But i had read various approaches towards this field under the research of superstring theory. I want to ask, what is Quantum loop gravity??
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  13. #12  
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    Quote Originally Posted by Heinsbergrelatz
    I want to ask, what is Quantum loop gravity??
    LQG is discussed accessibly a little at these links:

    http://www.aei.mpg.de/einsteinOnline...ang/index.html

    http://www.aei.mpg.de/einsteinOnline...cks/index.html


    Note: They are not specific to LCQ, so you may want something more pointed, even if just a wiki article on it.

    http://en.wikipedia.org/wiki/Loop_quantum_gravity
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  14. #13 answer my question! 
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    Do not get involved with quantum mechanics. Looking at GR alone, what can we say about various things? I say the inside of a BH does not exist. I say Weinberg 1972 is wrong saying gravity is nonlinear, as we cannot think of a thought experiment to verify it. I gave a list of papers that I want you to read and respond.
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  15. #14  
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    Can you define nonlinear, because I'm pretty sure you're not using the standard definition.
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  16. #15  
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    Quote Originally Posted by MagiMaster
    Can you define nonlinear, because I'm pretty sure you're not using the standard definition.
    See Weinberg, Gravitation, 1972. This is one of his key assumptions. You read the book and tell me what you think Weinberg meant. Since this book is a standard book, the definition is standard.
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  17. #16  
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    I don't have the book, nor can I get it for at least a month. Can you define what you mean when you say nonlinear. I don't even really care what Weinberg meant. I want to know what you mean.
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  18. #17 Weinberg 
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    Quote Originally Posted by MagiMaster
    I don't have the book, nor can I get it for at least a month. Can you define what you mean when you say nonlinear. I don't even really care what Weinberg meant. I want to know what you mean.
    Sorry, but I cannot help you. My point is that this text derives GR from two assumptions. I feel that these are not really correct. If I tell you what I mean, it is not the point. The point is that Weinberg's ideas are basic and standard, yet do not make sense. Cool it for a month. When you get the book, get back. You must read the book.
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  19. #18 Re: Weinberg 
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    Quote Originally Posted by Sanford
    Quote Originally Posted by MagiMaster
    I don't have the book, nor can I get it for at least a month. Can you define what you mean when you say nonlinear. I don't even really care what Weinberg meant. I want to know what you mean.
    Sorry, but I cannot help you. My point is that this text derives GR from two assumptions. I feel that these are not really correct. If I tell you what I mean, it is not the point. The point is that Weinberg's ideas are basic and standard, yet do not make sense. Cool it for a month. When you get the book, get back. You must read the book.
    Why? Shouldn't you be able to define your standard terms? Why are we expected to do the research for your claims and terminology? What is the incentive?
    Wise men speak because they have something to say; Fools, because they have to say something.
    -Plato

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  20. #19 Re: Weinberg 
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    Quote Originally Posted by Sanford
    Quote Originally Posted by MagiMaster
    I don't have the book, nor can I get it for at least a month. Can you define what you mean when you say nonlinear. I don't even really care what Weinberg meant. I want to know what you mean.
    Sorry, but I cannot help you. My point is that this text derives GR from two assumptions. I feel that these are not really correct. If I tell you what I mean, it is not the point. The point is that Weinberg's ideas are basic and standard, yet do not make sense. Cool it for a month. When you get the book, get back. You must read the book.
    So your question basically boils down to "help me understand this book"?
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  21. #20 the book 
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    This is a basic text for GR. If you claim to understand GR, you must understand this book. Let's try to understand the book, or else give clear reasons why you disagree.
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  22. #21  
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    Sanford - This is somewhat annoying to those of us who do not have a copy of the book, or who do not have ready access. As this is a discussion forum, now would be an appropriate time for you to discuss what your meaning is instead of tearing this thread off topic so you can go off on a diatribe about about a book written three decades ago.
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  23. #22 Re: Black holes 
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    Quote Originally Posted by Sanford
    I resent name calling! I resent being called a lunatic! People like you should be banned!
    Then don't make posts that clearly are the work of a crank.
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  24. #23 postulates 
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    Okay, here are the postulates of GR.

    the identity of gravitational and inertial masses.

    " The Einstein theory is itself an example of a non-linear theory in which the stress energy tensor vanishes in a mass zero zone", quote from Weinberg.

    "p. 155 R sub mu nu = 0 in empty space as T sub mu nu = 0. Weird, as of course empty space has gravitational energy if a mass is nearby.

    My question, which you seem offended by my merely asking, is what does Weinberg mean by a non-linear theory?

    Again, not what do I mean, but what does Weinberg mean?
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  25. #24 Re: postulates 
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    Quote Originally Posted by Sanford
    Okay, here are the postulates of GR.

    the identity of gravitational and inertial masses.

    " The Einstein theory is itself an example of a non-linear theory in which the stress energy tensor vanishes in a mass zero zone", quote from Weinberg.

    "p. 155 R sub mu nu = 0 in empty space as T sub mu nu = 0. Weird, as of course empty space has gravitational energy if a mass is nearby.

    My question, which you seem offended by my merely asking, is what does Weinberg mean by a non-linear theory?

    Again, not what do I mean, but what does Weinberg mean?
    As you have been told numerous times, general relativityis a non-linear theory because the partial differential equations known as the Einstein field equations are non-linear.

    A linear operator K is an operator such that K(ax+y)= aK(x) +K(y) for all scalars a and vectors x and y.

    Anyone studying mathematical physics, and general relativity qualifies, ought to know what linear means. In fact, I would expect any sophomore mathematics, physics or engineering student to be extremely familiar with the notion of linearity.

    Non-linear means "not linear".

    In the case of GR, the non-linearity arises because gravitational fields can interact with themselves, whereas in electrodynamics electromagnetic fields do not intereact with other electromagnetic fields.

    Anyone who does not understand these elementary points has no business making statements, as you have done, that general relativity is incorrect. If you do not understand the theory you have no business criticizing it.
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  26. #25  
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    @Sanford, even Newtonian mechanics is nonlinear, since is not linear. Why should GR be linear? (If you're saying that GR is not non-linear, you must mean that it is linear, right?)
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  27. #26 Linear 
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    Quote Originally Posted by MagiMaster
    @Sanford, even Newtonian mechanics is nonlinear, since is not linear. Why should GR be linear? (If you're saying that GR is not non-linear, you must mean that it is linear, right?)
    By nonlinear we mean the force acts with itself. I guess the word is confusing, as the force equation is not a linear equation, as you said. Newtonian gravitation is linear in the sense that if there are several masses present acting on a test mass, the total force on the test mass is the linear sum of the forces due to each mass. Mass A and Mass B act on mass m. The total force on m is the vector sum of the forces due to A and B. It is called linear because F total = FA + FB. Weinberg assumes that this is not the case in Einstein's theory. To get the force on mass m, we add an additional term, the attraction of the test mass m to the Field. The total force would consist of 3 terms, not 2 as in the Newtonian case.

    Thanks for asking. Your question helped me understand.
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