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honzik September 15th, 2017 01:48 PM

Black hole inside black hole
 
Hi, I have one question from cosmology:
can inside a black hole (that is defined as the spacetime region "inside" event-horison) reside another ("smaller") black hole? If yes, than black holes can have complicated but researchable structure (eg we can create hierarchy of black holes contained one inside another) ..
Thank you for any comments

Maschke September 15th, 2017 01:58 PM

Interesting. According to Hawking and evidently confirmed by experiment (not clear about that last part) black holes radiate huge amounts of energy via quantum tunneling. That is, although a photon can't escape the gravitational well of the black hole, there is always a nonzero probability that a photon inside the event horizon will simply appear outside it.

Now we can imagine that a photon tunnels out of a black hole to a region outside the event horizon, but now it's still stuck inside some larger region for some reason. I don't see why this couldn't be the case but I don't actually know anything about all this.

ps -- Photons tunneling out of black holes are called Hawking radiation. https://physics.stackexchange.com/qu...if-not-why-not

But I doubt there are meta-black holes outside the original one. Certainly not in contemporary cosmology.

Denis September 15th, 2017 03:17 PM

Quote:

Originally Posted by honzik (Post 580424)
(eg we can create hierarchy of black holes contained one inside another) ..

...and what purpose would that serve?

romsek September 15th, 2017 03:57 PM

Pretty sure once you've got conditions that will form a black hole it's just a matter of time before one forms.

If you were to have say conditions forming at the center of a mass distribution that allowed a black hole to form it would only be a matter of time before the rest of the matter distribution was incorporated into the black hole.

I don't think you could ever get a black hole forming within a matter distribution that has also coalesced into a black hole other than at very fast scales.

It would be interesting to calculate the time it takes for an exterior black hole to form once an interior once had already formed.

I suspect it would be on the order of milliseconds if not microseconds before the outer black hole coalesced.

Excuse my lack of formality, drinking whiskey this eve.

Denis September 15th, 2017 04:02 PM

Whoever figures out this HOLEistic mystery
gets a free triple whiskey...

honzik September 16th, 2017 04:47 AM

(For Denis: ...and what purpose would that serve?)

Pure scientists do not pose such questions. :-)
To answer broadly - "maybe to be able to explore black holes in a greater detail".

honzik September 16th, 2017 04:51 AM

A provocative question that relates it:
Can the whole Universe be considered as a big black hole? Because no light can escape from it. :-)

Denis September 16th, 2017 05:00 AM

The best place to ask that question is at your favorite drinking HOLE,
at THAT table where the ones who know everything sit...

Denis September 16th, 2017 05:22 AM

MUCH ADO ABOUT NOTHING
==================
There's a whopping huge cosmic interchange out there.
Half the time, "X" switches positions with "NOW".
And this is the solution to many ageless puzzles.
Follow me.

To get going, we must first solve this mystery:
-did it "start" or was it "always there"?
-was there "always nothing" or was there "something"?

If it "started", then right before "the start" there was "nothing".
Why? Simple: if there was "something", you wouldn't get a "start".
Instead, you would get a "carry on".
Agree? Good. Let's carry on.

Yes, I heard you...and I see it too: if we can prove that "nothing" is
impossible, then by default there was always something. So let's do a
nothing analysis.

If we try and imagine "nothing" existing, we can't: try it. Darn it, we're
always left with a handful of darkness, or a chunk of space, or a tiny wee
atom thay simply refuses to disappear. Sorry to disappoint you, "Big Bang"
pushers, but if as you say there was nothing, then all of a sudden, out of
nowhere, this mysterious "BANG", then tell us: what banged?

Well, fellow philosophers, we've managed to kick nothing out. Therefore,
there was always something. Hey: in other words, we got something out of
nothing...who says philosophers don't make jokes!

Think of it: there was always something. Always. You got it: we've just
established a past eternity, or a past infinity. Good work.

Gee, since past infinity means no beginning, then it automatically follows
that there is no ending: you can't have one without the other. Hey, look
at what we've just done: established a future eternity, in other words,
a future infinity...Wow-Wee.

Hey-hey, we're really getting somewhere. We now all agree on a two-way
infinite flow. Let's depict this using a simple straight line. Let's show
where we are "NOW" at the middle of that line, the "past" on the left, and
the "future" on the right. Let's see:
Code:

                                                    NOW
                                                        |
        <_________PAST____________|_________FUTURE__________>

Clear? Sure is. Before we proceed further toward "The Answer", let's pause
here and reflect deeply on our "two-way infinity" diagram. We can clearly
see two baffling facts:
1) Since infinity is equal to infinity (as 2 equals 2) then the past is
always equal to the future, no matter when the "NOW" is.
2) Therefore, we always were, always are and always will be "right in the
middle of it all".

Forward: "The Answer" awaits. It has been proposed and it is believed that
space is curved, that there is no such animal as a straight line, and that
everything (not only woman) moves in a curvy fashion; sort of elliptical.

Well, always "being straight" ain't all that much fun, so let's accept this
curvature concept. If we don't, then we gotta leave our "two-way infinity"
diagram the way it is, with stuff moving left and right eternally straight
...and that's boooooring...

Ok dokay. Now, let's apply this curvistic and ellipsic knowledge to our
infinite flow diagram. And here's what we get:
Code:

                        ------ --->    X    <-----------
                      /                                          \
                      /                                            \
                      \                                            /
                      \                NOW                  /
                        ^__PAST___|___FUTURE__^

How does that grab you, honey? We can clearly see, beyond the shadow of
Galileo, that not only is the past heading toward the future, but also that
the future is heading toward the past. Hey: maybe we've just discovered the
origin of the expression "the past always catches up with you".

Finally, we're at "The Big Cosmic X:NOW Interchange". For the 64 thousand
dollar question: what the heck happens at point "X" when these 2 rushing
infinities meet? Big crash? Well, don't worry. It's very simple. Since all
is smooth and symmetrical out there, the "NOW" and the "X" will simply
change places, and all carries on as before...ye olde positional swap.
Look see:
Code:

                        __PAST______FUTURE__
                      /              |                    \ 
                      /            NOW                  \
                      \                                      /
                      \                                    /
                        ----->    X      <-------

Ain't it all clear now? Life carries on, another "X" to shoot for, meet at
"X" again, perform the cosmic hop...eternity right and left. In other words,
we're all being taken for an infinite ride.

I hear some of you objecting: that last flow diagram shows that for half
the time, the past is moving ahead while the future is in reverse gear.
Good point. But you'll agree that this does answer many puzzling questions:
1) Why do we feel we're wasting half our time living in the past?
2) Why do we often feel there's no future ahead?
3) Why do we get the feeling we're headed in the wrong direction?

Well, let's figure out where we are after all this. We've established that
we're always right in the middle of things, we're all in for a long ride,
there's a big "X" somewhere out there, and we're getting nowhere fast half
the time...to tell you the truth, I'm still as confused as ever.

It was nice, you know: on the farm, 5 years old, real secure on that sready
piece of flat earth. All I had to do was stay put, keep away from that deep
edge a couple of miles off. But they started to educate me: all that
rotating, ellipsing and spinning stuff. Well, think I'll forget all about
these deep questions. No more. Over and out.

Well...now...maybe...just maybe. Just maybe it did all start with nothing.
How can I make this tiny wee atom vanish? Let's give it another shot. Now,
if I imagine a huge pair of magical hands cupping up everything, squeezing
it all down, then making it all vanish with the big POUFF like they do in
magic shows...Ya! That's it! I see nothing!

...Oh no: that big pair of hands is still there.
...Suddenly, I'm very, very, very tired.
...I hear marbles dropping all over the place.
...They're coming to get me...HA-HA! HA-HA!

jonah September 16th, 2017 10:06 AM

Beer soaked comment follows.
Quote:

Originally Posted by Denis (Post 580455)
MUCH ADO ABOUT NOTHING
==================
There's a whopping huge cosmic interchange out there.
Half the time, "X" switches positions with "NOW".
And this is the solution to many ageless puzzles.
Follow me.....

Still funny.
It just never gets old.
Wish I had such an epiphany while hopelessly hammered.

jonah September 17th, 2017 11:39 AM

Beer soaked recollection follows.

Just remembered why that black hole inside a black hole sounded familiar. It was the plot behind this episode of a show that I watched with my young brother back then.
The Tick vs. The Big Nothing.
https://m.youtube.com/watch?v=bGdvbxFQspE

Joppy September 18th, 2017 03:59 PM

A hole in one.

Benit13 October 2nd, 2017 07:27 AM

Quote:

Originally Posted by honzik (Post 580424)
Hi, I have one question from cosmology:
can inside a black hole (that is defined as the spacetime region "inside" event-horison) reside another ("smaller") black hole? If yes, than black holes can have complicated but researchable structure (eg we can create hierarchy of black holes contained one inside another) ..
Thank you for any comments

Who knows what the hell is in a black hole. Is it even meaningful to ask the question since they have (approximately?) zero volume? :p


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