Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics.relativity > #452784

Re: event horizon.

Show all headers | View raw

Tom Roberts wrote:

> On 3/14/18 1:32 AM, Simon Roberts wrote:
>> What happens when the event horizon's radius becomes smaller than its
>> black hole?
> Can't happen. The event horizon is the boundary of the black hole.
> 
> Note, however, that "radius" is not really applicable. The
> radius of a sphere would be measured inside the sphere, but
> the causal structure of the manifold inside the horizon of
> a black hole does not permit that.

I don’t know about you, but I can measure the radius of a sphere from 
outside the sphere just as well.

> Also there are black holes whose horizons are not spherical.

Yes, rotating ones (Kerr or Kerr–Newman metric), which apparently applies to 
most of them (due to conservation of angular momentum).


PointedEars
-- 
Q: Where are offenders sentenced for light crimes?
A: To a prism.

(from: WolframAlpha)

Back to sci.physics.relativity | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

event horizon. Simon Roberts <retenshun@gmail.com> - 2018-03-13 23:32 -0700
  Re:event horizon. Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com> - 2018-03-14 08:14 +0100
    Re: event horizon. mlwozniak@wp.pl - 2018-03-14 00:53 -0700
    Re:event horizon. Térov Balónky <iytn@yeicenlw.ik> - 2018-03-14 15:59 +0000
      Re:event horizon. "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2018-03-14 09:19 -0700
    Re:event horizon. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-14 18:18 +0100
  Re: event horizon. Tom Roberts <tjroberts137@sbcglobal.net> - 2018-03-14 22:15 -0500
    Re: event horizon. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-15 16:29 +0100
      Re: event horizon. Gary Harnagel <hitlong@yahoo.com> - 2018-03-15 09:20 -0700
      Re: event horizon. Térov Balónky <iytn@yeicenlw.ik> - 2018-03-16 14:48 +0000
      Re: event horizon. Tom Roberts <tjroberts137@sbcglobal.net> - 2018-03-19 10:36 -0500
        Re: event horizon. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-20 00:56 +0100
          Re: event horizon. Tom Roberts <tjroberts137@sbcglobal.net> - 2018-03-20 14:13 -0500
            Re: event horizon. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-20 20:56 +0100
              Re: event horizon. Steven Carlip <carlip@physics.ucdavis.edu> - 2018-03-22 09:17 -0700
                Re: event horizon. Darryl Fletcher <lu@ewiwwe.tt> - 2018-03-22 16:37 +0000
                Re: event horizon. Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-22 18:10 +0100
                Re: event horizon. JanPB <filmart@gmail.com> - 2018-03-23 13:13 -0700
                Re: event horizon. Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2018-03-22 14:54 -0700
                Re: event horizon. Koobee Wublee <koobee.wublee@gmail.com> - 2018-03-22 23:06 -0700
            Re: event horizon. Koobee Wublee <koobee.wublee@gmail.com> - 2018-03-20 22:51 -0700
              Re: event horizon. Odd Bodkin <bodkinodd@gmail.com> - 2018-03-21 11:37 +0000
                Re: event horizon. Koobee Wublee <koobee.wublee@gmail.com> - 2018-03-22 13:51 -0700
              Re: event horizon. JanPB <filmart@gmail.com> - 2018-03-23 13:31 -0700
                Re: event horizon. Tom Roberts <tjroberts137@sbcglobal.net> - 2018-03-23 15:59 -0500
                Re: event horizon. Emma Blazer <aemb@wmopswxa.as> - 2018-03-23 22:19 +0000
                Re: event horizon. JanPB <filmart@gmail.com> - 2018-03-23 15:43 -0700
                Re: event horizon. Koobee Wublee <koobee.wublee@gmail.com> - 2018-03-23 22:06 -0700
                Re: event horizon. mlwozniak@wp.pl - 2018-03-23 23:05 -0700
                Re: event horizon. Emma Blazer <aemb@wmopswxa.as> - 2018-03-24 10:55 +0000
    Re: event horizon. JanPB <filmart@gmail.com> - 2018-03-19 20:42 -0700
      Re: event horizon. Tom Roberts <tjroberts137@sbcglobal.net> - 2018-03-23 10:37 -0500
    Re: event horizon. Koobee Wublee <koobee.wublee@gmail.com> - 2018-03-20 22:44 -0700
  Re: event horizon. numbernumber1964@gmail.com - 2018-03-20 13:55 -0700
    Re: event horizon. Odd Bodkin <bodkinodd@gmail.com> - 2018-03-20 23:02 +0000
  Re: event horizon. alsor@interia.pl - 2018-03-20 16:12 -0700
  Re: event horizon. numbernumber1964@gmail.com - 2018-03-22 15:24 -0700
    Re: event horizon. Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2018-03-22 17:14 -0700
    Re: event horizon. pnalsing@gmail.com - 2018-03-22 17:32 -0700
  Re: event horizon. numbernumber1964@gmail.com - 2018-03-23 10:37 -0700
    Re: event horizon. Prokaryotic Caspase Homolog <prokaryotic.caspase.homolog@gmail.com> - 2018-03-23 13:32 -0700
  Re: event horizon. numbernumber1964@gmail.com - 2018-03-23 10:38 -0700
    Re: event horizon. moroney@world.std.spaamtrap.com (Michael Moroney) - 2018-03-24 01:36 +0000

csiph-web