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Thread: Hawking now believes there are no black holes

  1. #1 Hawking now believes there are no black holes 
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    Can we still call people "black hole crackpots" if they believe there are no black holes?

    Stephen Hawking: 'There are no black holes' : Nature News & Comment

    In an arXiv article posted in late January, Hawking writes that a black holes will not form based upon considerations of anti de Sitter space and conformal field theory.

    He defines a black hole as a region from beyond which light cannot escape to infinity.

    He seems to be concerned with quantization of spacetime utilizing conformal string theory. Can anyone clarify his arguments?
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  2. #2  
    Administrator Markus Hanke's Avatar
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    Can anyone clarify his arguments?
    Hawking did not say anything about black holes not existing; his paper is rather about how we need to re-think the structure of these objects once quantum effects are taken into account.
    As for a detailed explanation - it might be good to await his actual paper with the maths in it.
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    Quote Originally Posted by Markus Hanke View Post
    Hawking did not say anything about black holes not existing; his paper is rather about how we need to re-think the structure of these objects once quantum effects are taken into account.
    As for a detailed explanation - it might be good to await his actual paper with the maths in it.
    Hello Markus.
    Yes, he did not say black holes do not exist. I didn't say he did.

    Rather he advances a propositon an event horizon is, instead, an apparent horizon, and provides motivational argument. The strongest statement he makes is that his proposition is the only resolution to the information paradox that preserves CPT.
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    Administrator Markus Hanke's Avatar
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    Quote Originally Posted by Useful Idiot View Post
    Yes, he did not say black holes do not exist. I didn't say he did.
    I was referring to the title of this thread.
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    The article's intro makes it sound like he's saying there are no black holes.

    Quote Originally Posted by Article
    Most physicists foolhardy enough to write a paper claiming that “there are no black holes” — at least not in the sense we usually imagine — would probably be dismissed as cranks. But when the call to redefine these cosmic crunchers comes from Stephen Hawking, it’s worth taking notice.

    But really he's just redefining them by eliminating the event horizon. It's clear that he's been obsessed with solving the information paradox while he still has time to do it. I know I certainly hope he achieves it.

    Not sure what to think of this new solution. It's better than the many universes solution.
    A mathematician and an engineer were at a party. An older colleague of theirs was there with his daughter. The two each asked if they could speak to her. He said it was ok, but they had to approach her by going half way across the room, then stop, then half way again and stop and proceed in that manner. The mathematician realized that he would never reach her and gave up. The engineer determined that he could get close enough to talk. --Approximate retelling of a joke by my math teacher.
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    Quote Originally Posted by Markus Hanke View Post
    I was referring to the title of this thread.
    Well, my title doesn't claim Hawking made this claim. "Believe" is a fuzzy word. Maybe you were thinking of the Nature article, where the title is both a hook and false statement.

    It's been 30 days since the the arXiv article.


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    Hawking is arguing two things. 1) The firewall idea doesn't work, 2) He has an alternative.

    Formally he says,

    A) BH & ADS-CFT & CPT = False.

    BH are black holes defined as the "regime from which light cannot escape to infinity."

    ADS-CFT is any string theoretic quantum gravity theory. As far as I know nobody has a undisputed theory of quantum gravity, so this raises the question, what does "ADS-CFT mean to Hawking?"

    We can take this in a few ways. BH & CPT mean ADS-CFT = False, or BH & ADS-CFT implies CPT is false. But obviously the thrust of the argument is to imply BH = False.

    Kojax,

    Hawking is implicitly arguing there are no black holes per the definition he give for a black hole. A black hole is a region and a black hole's event horizon is it's boundary. He proposes, under the conditions given abobve, distinct differences between an "event horizon" and an "apparent horizon". He also proposes a distinct difference for the interior. Per proposition, stuff doesn't cross the apparent horizon.

    Should this proposition become accepted, we can still call the interior a "black hole" and the Hawking's "apparent horizon" an "event horizon". Labels are a matter of choice. I expect this is what shall occur. It is human nature not to be seen are wrong. A relabeling will cure this ill.
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    The only physically plausible construction of a black hole, something with a solution, but not causal connection to an exterior observer, is a spherically collapsing, coherent neutrino field. Now, intelligent life may be able to accomplish this, but the probability of nature obtaining something like this, in a finite mass universe is entropically remote.

    Do we humans--you and I---so crave a mystery, that we forego objectivity?

    Or maybe general solutions to general relativity are so difficult to find, we just haven't found less symmetrical solutions. Well--not we, but those looking for them (Let Michio Kaku take credit for the work of others.).
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