The Naked Scientists

The Naked Scientists Forum

Author Topic: How Deep is a Black Hole?  (Read 8255 times)

Offline Gordian Knot

  • Sr. Member
  • ****
  • Posts: 165
    • View Profile
How Deep is a Black Hole?
« on: 16/02/2012 15:08:27 »
Someone mentioned on a segment of The Universe that a Black Hole is only called a "hole" because things fall into it (and don't come out). Got me to thinking how deep a hole is a black hole anyway?

Are we talking a cosmic sized puddle? Or something of enormous depth. We often see depictions of a black hole being a wormhole that doesn't have a bottom at all, but rather comes out in a different part of the universe.

Does science have a clue? If not, what is the prevailing theory on the subject.


 

Offline CliffordK

  • Neilep Level Member
  • ******
  • Posts: 6321
  • Thanked: 3 times
  • Site Moderator
    • View Profile
Re: How Deep is a Black Hole?
« Reply #1 on: 16/02/2012 19:25:07 »
A wormhole might be possible, but an unlikely explanation of a black hole.

If you take the classic definition of a black hole being a super dense mass surrounded by an event horizon.  The question would be the density of the matter within the black hole.  Some theories indicate a point singularity, but that may be too great of a density.  It is likely that no type of atmosphere could exist within the event horizon, as gravity stopping light would surely crush any particles containing mass onto the central body.

So, the maximum depth would be half the diameter, or the radius of the event horizon.  Depending on the volume of the central body, it could be a lot less.

Do we need some kind of odd contracting space as part of the calculations too?
 

Offline mojo4567

  • First timers
  • *
  • Posts: 3
    • View Profile
Re: How Deep is a Black Hole?
« Reply #2 on: 17/02/2012 22:37:38 »
A wormhole might be possible, but an unlikely explanation of a black hole.

Yes I always thought of black holes in the way that the STOR show it as a huge dip in the fabric of space so dense that it just crushed anything that went into it but never as a wormhole
 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Re: How Deep is a Black Hole?
« Reply #3 on: 18/02/2012 02:53:50 »
You can't drop a measuring tape down into a black hole to measure its depth in the way that you can a hole on the earth, so how would you propose measuring the "depth" of a black hole?  Depending on how you choose to measure it, the answer could differ.
 

Offline Don_1

  • Neilep Level Member
  • ******
  • Posts: 6890
  • Thanked: 7 times
  • A stupid comment for every occasion.
    • View Profile
    • Knight Light Haulage
Re: How Deep is a Black Hole?
« Reply #4 on: 18/02/2012 17:07:36 »
Perhaps it would have no depth?!?!?
 

Offline syhprum

  • Neilep Level Member
  • ******
  • Posts: 3812
  • Thanked: 19 times
    • View Profile
Re: How Deep is a Black Hole?
« Reply #5 on: 18/02/2012 17:46:34 »
I think that we should consider the density of the materiel in the BH to be at the Planck density, very high but not infinite.
this would result in a very small core hence the depth would differ little from the EH radius.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Re: How Deep is a Black Hole?
« Reply #6 on: 18/02/2012 23:06:30 »
It's a interesting question. If we take the famous muon hitting Earth the explanation to why it can travel so far is the Lorentz contraction it experience from its own frame of reference. But when we come to 'gravity' as in a black hole, there is expected to be the opposite (expansion) from the frame of reference of someone passing the event horizon.

So, is gravity and what you see from outside a gravitational well equivalent to a 'velocity/speed'? From the point of the hurling (uniformly so) spacecraft in deep space, SpaceTime contracts. From the frame of reference of that same Spaceship uniformly moving inside a event horizon, SpaceTime expands.
« Last Edit: 18/02/2012 23:08:35 by yor_on »
 

Offline acecharly

  • Sr. Member
  • ****
  • Posts: 171
    • View Profile
Re: How Deep is a Black Hole?
« Reply #7 on: 24/02/2012 20:05:16 »
Is it possible the matter is under such enormous pressure that it simply turns to pure energy and takes up no space at all like it may have done before the big bang? is this not similar to what happens in a H bomb, where all the mass is forced together so close that the strong nuclear force takes effect producing alot of energy?
 

Offline greeniemax

  • Full Member
  • ***
  • Posts: 76
    • View Profile
Re: How Deep is a Black Hole?
« Reply #8 on: 25/02/2012 09:31:14 »
Black hole isn't a real hole, its a super massive object in the universe.

The size of this object would be smaller as the mass gets larger because of higher gravitational pull it gets smaller. But you could find the actual size of black hole from its event horizon by using GR.

Light bends around Sun, thus we have to know how much light bend, using this we know that if light wants to travel outside the event horizon it should bend 180 Deg, that is where black hole is form, there could be larger or smaller black holes but that is the limit at which black hole is formed.
 

The Naked Scientists Forum

Re: How Deep is a Black Hole?
« Reply #8 on: 25/02/2012 09:31:14 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length