Defining a Singularity

Discussion in 'Physics & Math' started by MacM, Aug 17, 2004.

  1. kula (Memes enclosed) within Registered Senior Member

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    So is it too philsosophical to say that, what we consider matter, particles, wavelengths etc, could not exist in a singularity/would be annihilated because they need to have a quality of size ?

    What does the mathematical model predict ? Is matter converted to some state, continually compressed or returned to some quantum state ?

    I understand what you are saying about our models not being up to the job, but cant we use some of the available data to rule some possibilities out, for example, we can say that gravity is not annihilated in a black hole therefore a) There isnt a singularity or b) singularities have a property of gravity.

    Or are our mathematical models so inadequate that we simply cant relate these conditions to our understanding of energy ?

    I'm not being lazy, i will check these out myself as well !
     
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  3. Pete It's not rocket surgery Registered Senior Member

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    I think that the General Relativy model (the one that describes black holes) simply predicts that all mass-energy entering a black hole will end up in a point at the singularity.

    I don't think that any model specifically dictates that non-zero size is a necessary property of matter (I think that an electron is actually considered to be pointlike).

    The GR model is clear on this one. According to GR, gravity around a black hole is completely independent of anything inside the event horizon - the gravity field is a fossil field caused in the past by infalling matter, and locked in place by the extreme curvature at the event horizon. Nothing inside the event horizon can affect anything outside it.

    The models do not include effects that we know must come into effect in extreme conditions. The model can be applied in those conditions, but the results are meaningless. It's like applying Newtonian mechanics to relativistic situations - you get results, but those results don't correspond to reality.
     
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  5. RawThinkTank Banned Banned

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    Said who ?


    Said who ?

    So can we use these temperatures to build a Time machine ?
     
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  7. fadingCaptain are you a robot? Valued Senior Member

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    So, does the scientific world think singularities actually physically exist? I was under the impression they are a mathematical circumstance. (I really don't have time to read through this thread)
     
  8. Quantum Quack Life's a tease... Valued Senior Member

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    I don't think theyu have observed a black hole either....for that matter ( or should I say lack of it)
     
  9. fadingCaptain are you a robot? Valued Senior Member

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    But haven't we seen what appears to be event horizons?
     
  10. MacM Registered Senior Member

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    I believe the answer to that is NO!. Black Holes are theorethical based on indirect evidence such as seeing star material being ripped off and streaming into a general location and vanishing or motion of other bodies that we can see being affected by some gravity (massive object) that we can't see.

    They are predicted mathematically but not seen.


    The Black Hole is so named because it does not allow light or energy which we can percieve (see) to escape. It is therefore invisible.
     
  11. James R Just this guy, you know? Staff Member

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    Black holes tend to be surrounded by accretion discs, which produce enormous energy outputs which cannot be accounted for by any other astrophysical processes. Thus, they are not solely mathematical constructs, as MacM would have you believe. The chances of black holes NOT existing are very small indeed.
     
  12. MacM Registered Senior Member

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    Gotta watch you every minute. You suggest here that I would have people believe Black holes don't exists. I have never anywhere suggested that. I have said and do say that the claim of a singularity at the center and its mathematical infinites do not exist in reality which show the mathematics are in need of physical model so as to properly limit their application.
     
  13. James R Just this guy, you know? Staff Member

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    How do you know the singularity at the centre of a black hole doesn't exist in reality? Show me your proof, please.
     
  14. MacM Registered Senior Member

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    Ditto. Please show me an infinite mass density and infinite gravitation force and I'll conceed. Thank you for the futile exercise in show me your proof. It is indeed a two way street.
     
  15. James R Just this guy, you know? Staff Member

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    MacM:

    You are the only one here making definite statements like "Singularities don't exist in reality." As I scientist, I keep an open mind. I have never said that singularities do exist in reality; nor have I ever said they do not. I don't know. But it appears that you do, via some mystical power that only you seem to possess.

    The fact that you regard this exchange as a "futile exercise" shows just how far you have to go to appreciate what scientists do.
     
  16. MacM Registered Senior Member

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    Actually you too possess the same ability. You simply choose to not use it.

    While I believe you admit that nothing physical can become infinite for what ever reason you choose to not apply that rule to the properties of the Black Hole. That is curious.

    Correction - "Do not do".
     
  17. kula (Memes enclosed) within Registered Senior Member

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    Ive had a thought.....

    wait for it.......

    If a singularity is infinite, wouldnt gravity also be infinite and suck the whole universe into the black hole ?
     
  18. MacM Registered Senior Member

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    It is almost a play on words. Infinite density in presence of "zero" volume - hence no mass = "o" gravity also.
     

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