Notices
Results 1 to 9 of 9

Thread: How do we know that black holes form?

  1. #1 How do we know that black holes form? 
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,046
    I asked this question over on the physicsforum, but the thread seems to have stagnated, so I figure I might as well ask it here also.

    Suppose that objects that become massive/dense enough to become black holes were prevented from collapsing by time dilation. What would we see in that region of space?

    There would still be some electromagnetic radiation coming from that region, but it would be red shifted to such an incredible degree that it would be at an incredibly low frequency. Possibly lower than the kiloherz, or even herz range. (Like a small fraction of a herz). We'd need a gigantic antenna just to detect it, and even then we'd have a very hard time accurately determining what direction it is coming from.

    Time would never completely freeze in this region of space. It would just appear to get slower and slower. In practice, communication might become practically very difficult, but in theory it would always be possible to send an EM signal into the interior of this region, and get a response back.

    Anyway, I'm starting to think that maybe there is no need for a solution to Hawking's Black hole Information Paradox, simply because there is no paradox. No information has been lost. Infinity years from now it might get lost, but that's well.... infinity years in the future.

    Black hole information paradox - Wikipedia, the free encyclopedia


    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Ph.D.
    Join Date
    Jul 2008
    Location
    New York State
    Posts
    857
    Your partly on the right track. For an outside observer the black hole would never form (time dilation). However in the reference frame of the colapsing star there is no time dilation.


    Reply With Quote  
     

  4. #3  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,046
    The thing is, we can't choose either perspective and give it primacy. We have to choose both. And the thing about groups is a group is only as fast as its slowest member.

    When the two regions of space interact, they do so using both perspectives simultaneously. And the interaction is what we are interested in looking at. If all we want to look at is the local, then we can pretty much ignore the gravity effects altogether.

    A point mass in a gravitational field feels itself to be moving in an inertial manner anyway, doesn't it? Gravitational effects only become apparent when we compare different objects in different regions of the field.
    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  5. #4  
    Forum Masters Degree Implicate Order's Avatar
    Join Date
    Oct 2013
    Location
    27.4679 S, 153.0278 E
    Posts
    610
    Quote Originally Posted by kojax View Post
    The thing is, we can't choose either perspective and give it primacy. We have to choose both.
    Not with observer dependent dualities which we commonly face in QM. It is either one interpretation OR the other. Not both interpretations combined. Each interpretation needs to be fully consistant in their own right. The duality according to Susskinds Black Hole Complementarity solution sought to resolve the information paradox and is attributed to the fact that the structure of the vacuum appears to be dependent on the frame of reference that is doing the measuring.
    Quidquid latine dictum, altum videtur
    Reply With Quote  
     

  6. #5  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,046
    Quote Originally Posted by Implicate Order View Post
    Quote Originally Posted by kojax View Post
    The thing is, we can't choose either perspective and give it primacy. We have to choose both.
    Not with observer dependent dualities which we commonly face in QM. It is either one interpretation OR the other. Not both interpretations combined. Each interpretation needs to be fully consistant in their own right. The duality according to Susskinds Black Hole Complementarity solution sought to resolve the information paradox and is attributed to the fact that the structure of the vacuum appears to be dependent on the frame of reference that is doing the measuring.
    I think Susskind's approach is very novel, but he still starts from the point where a singularity has already formed before making his arguments. I'm thinking instead that the singularity never forms in the first place.

    Imagine we have a neutron star with 15% of its mass still located outside the Schwarzchild radius for an object of its mass. No part of that star lies inside a singularity yet. Not even the very core. Time has not completely stopped for any part of that star, not even at the core. However, time should appear to be flowing very slowly in all regions of the neutron star.

    Now imagine that, after a very long while, we observe that only 1% of its mass still lies outside the Schwarzchild radius. Has time stopped yet in any region of the star? No. Not even at the core. But it probably appears to be moving really really slow.

    Going by degrees, it should take infinity years for the last 1% or 0.0000001% or whatever, of the neutron star's mass to find its way inside the Schwartzchild radius, no matter how strong the balance of forces favors a collapse. Because time dilation keeps pushing the event back further. The star is procrastinating its collapse. Always putting it off until "later".
    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  7. #6  
    Forum Masters Degree Implicate Order's Avatar
    Join Date
    Oct 2013
    Location
    27.4679 S, 153.0278 E
    Posts
    610
    Quote Originally Posted by kojax View Post
    I think Susskind's approach is very novel, but he still starts from the point where a singularity has already formed before making his arguments. I'm thinking instead that the singularity never forms in the first place.
    I am going to have to go back and have a read of 'the Black Hole Wars' by Susskind to refresh on his ideas as IIRC his approach to Quantum Gravity was to conclude that there is no such singularity for the accelerating observer. Nothing 'exists' on the other side of the event horizon for the accelerating observer and like a Rindler Horizon or De-Sitter horizon, the event horizon of a black hole represents a universal boundary for the accelerating observer......not too dissimilar to your ideas. :-)
    Last edited by Implicate Order; September 30th, 2014 at 02:42 AM.
    Quidquid latine dictum, altum videtur
    Reply With Quote  
     

  8. #7  
    Moderator Moderator Markus Hanke's Avatar
    Join Date
    Nov 2011
    Location
    Ireland
    Posts
    7,179
    Quote Originally Posted by kojax View Post
    I asked this question over on the physicsforum, but the thread seems to have stagnated
    Apologies...you mightn't have seen the announcement, but I had made a decision to resign from all moderator duties and active participation on that forum; that is why I never came back to you on that thread.
    Reply With Quote  
     

  9. #8  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,046
    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by kojax View Post
    I asked this question over on the physicsforum, but the thread seems to have stagnated
    Apologies...you mightn't have seen the announcement, but I had made a decision to resign from all moderator duties and active participation on that forum; that is why I never came back to you on that thread.
    Why did you do that? Just don't have enough time?

    You'll certainly be missed.


    Your participation in the thread over there certainly helped me formulate the question better when I presented it here.
    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  10. #9  
    Moderator Moderator Markus Hanke's Avatar
    Join Date
    Nov 2011
    Location
    Ireland
    Posts
    7,179
    Quote Originally Posted by kojax View Post
    Why did you do that? Just don't have enough time?
    Yes, that is basically it. I spent too much time in Internet forums, to the extent that my self-studies suffered because of it, so I withdrew from a number of sites to free up some resources.
    Reply With Quote  
     

Similar Threads

  1. Black holes, Dumb holes and accelerating EoS
    By leohopkins in forum Physics
    Replies: 1
    Last Post: October 13th, 2013, 07:19 AM
  2. Black holes???
    By ASTROPHYSICIST137 in forum Astronomy & Cosmology
    Replies: 0
    Last Post: January 10th, 2010, 02:22 PM
  3. White holes are the opposit of black holes in the univers.
    By Victor2009 in forum Astronomy & Cosmology
    Replies: 9
    Last Post: May 21st, 2009, 08:12 AM
  4. Regarding Black Holes
    By madscientist in forum Physics
    Replies: 4
    Last Post: November 28th, 2007, 01:54 PM
  5. black holes
    By AlexP in forum Astronomy & Cosmology
    Replies: 14
    Last Post: October 12th, 2006, 11:07 AM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •