Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: katieHaylor on 03/10/2018 15:58:42

Title: What's a black hole made of?
Post by: katieHaylor on 03/10/2018 15:58:42
David asks:

Would a black hole be made up of sub-atomic particles we have not yet detected, or made up of dark matter, which we have not yet detected?

What do you think?
Title: Re: What's a black hole made of?
Post by: Bill S on 03/10/2018 16:33:38
Possibly, normal matter/energy in an abnormal state.

Wait for it! Someone's going to say: "What is normal?". :)
Title: Re: What's a black hole made of?
Post by: jeffreyH on 03/10/2018 22:13:04
What is a black hole?
Title: Re: What's a black hole made of?
Post by: evan_au on 03/10/2018 22:54:52
A black hole is made up of anything that has mass and/or energy.

Quote
Would a black hole be made up of sub-atomic particles we have not yet detected, or made up of dark matter, which we have not yet detected?
Both of these sound like they would have mass, so yes.
It is also made up of normal matter and light, which also have mass and/or energy.

However, what form it takes when it reaches the central singularity, we can't say, because that is shrouded by the event horizon.
Title: Re: What's a black hole made of?
Post by: jarvisss on 04/10/2018 07:35:59
When I will be 60, before my death I want to jump in the rocket and fly into the black hole.
Title: Re: What's a black hole made of?
Post by: Bill S on 05/10/2018 10:30:48
Hi Jarvisss, welcome.

You might think differently when you are 59. :)
Title: Re: What's a black hole made of?
Post by: jeffreyH on 05/10/2018 13:47:15
I would hazard a guess that you would be dead before you reached your destination.
Title: Re: What's a black hole made of?
Post by: Halc on 05/10/2018 13:59:22
I would hazard a guess that you would be dead before you reached your destination.
Only the little ones kill you before you get there.  One can cross the event horizon of a big one without even noticing.  OK, it will still kill you soon enough, but a similar death to being spun at a fatal RPM, which isn't the sort of way I'd choose to go out given a choice.

Answer to the OP then:  It would then be made of you!  You are what you eat.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 05/10/2018 16:12:11
David asks:

Would a black hole be made up of sub-atomic particles we have not yet detected, or made up of dark matter, which we have not yet detected?

What do you think?
Any kind of matter which falls toward a black hole gets stuck just outside the event horizon and never passes it. That's why they used to be called "frozen stars." The matter at the center is of an unknown makeup since any kind of matter gets compressed, first so that everything becomes neutrons and then compressed further. To know more requires a yet unknown quantum theory of gravity.
Title: Re: What's a black hole made of?
Post by: guest45734 on 06/10/2018 19:07:18
David asks:

Would a black hole be made up of sub-atomic particles we have not yet detected, or made up of dark matter, which we have not yet detected?

What do you think?
Any kind of matter which falls toward a black hole gets stuck just outside the event horizon and never passes it. That's why they used to be called "frozen stars." The matter at the center is of an unknown makeup since any kind of matter gets compressed, first so that everything becomes neutrons and then compressed further. To know more requires a yet unknown quantum theory of gravity.

Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?

Regards the matter inside a BH, the laws of thermodynamics "ALWAYS" apply. If matter is compressed inside a BH its going to get very very hot eventually breaking down to fundamental particles etc etc.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 06/10/2018 20:25:03
Quote from: dead cat
Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?
Yes. See: https://en.wikipedia.org/wiki/Black_hole#Gravitational_collapse
Quote
Even though the collapse takes a finite amount of time from the reference frame of infalling matter, a distant observer would see the infalling material slow and halt just above the event horizon, due to gravitational time dilation. Light from the collapsing material takes longer and longer to reach the observer, with the light emitted just before the event horizon forms delayed an infinite amount of time. Thus the external observer never sees the formation of the event horizon; instead, the collapsing material seems to become dimmer and increasingly red-shifted, eventually fading away.
The derivation for the speed of light in a gravitational field is on my website at:
http://www.newenglandphysics.org/physics_world/gr/c_in_gfield.htm

The same thing applies to all matter because all matter is slower than light.
See Eq 10.
Title: Re: What's a black hole made of?
Post by: Bill S on 06/10/2018 21:24:04
Quote from: Pete
Any kind of matter which falls toward a black hole gets stuck just outside the event horizon and never passes it.

Quote
Even though the collapse takes a finite amount of time from the reference frame of infalling matter, a distant observer would see the infalling material slow and halt just above the event horizon, due to gravitational time dilation.

While your quote is apparently accurate in the RF of the distant observer; would it not be true that in its own RF, the infalling matter not only reaches, but crosses the event horizon?
Title: Re: What's a black hole made of?
Post by: Bill S on 06/10/2018 21:42:51
Could this be nothing more than a recurrence of Zeno’s paradox?  If we consider the situation from the point of view of the outside observer as an example of asymptotic decay, in which the infalling object is not simply stuck for ever in the same state, but is gradually vanishing, with its progress being recorded by an asymptotic curve, then, in theory, it would never actually vanish (although it would be red-shifted beyond the visible spectrum), but in reality, like Zeno’s arrow, it would come to a conclusion.  In other words, it would vanish.  Maybe, this is the simplest explanation.         
Title: Re: What's a black hole made of?
Post by: guest45734 on 06/10/2018 21:55:15
Quote from: Pete
Any kind of matter which falls toward a black hole gets stuck just outside the event horizon and never passes it.

Quote
Even though the collapse takes a finite amount of time from the reference frame of infalling matter, a distant observer would see the infalling material slow and halt just above the event horizon, due to gravitational time dilation.

While your quote is apparently accurate in the RF of the distant observer; would it not be true that in its own RF, the infalling matter not only reaches, but crosses the event horizon?

You will notice Peter answered  "YES" to my question are you taking the piss. Obviously if matter is accelerated towards the event horizon it will pass on towards the centre of the BH unless of course the object suddenly decelerates. What is observed and what is happening is all relative, to an outside observer of our universe time does not exist, it only exists in our reference frame.

Quoting the wiki link
"Oppenheimer and his co-authors interpreted the singularity at the boundary of the Schwarzschild radius as indicating that this was the boundary of a bubble in which time stopped. This is a valid point of view for external observers, but not for infalling observers. Because of this property, the collapsed stars were called "frozen stars", because an outside observer would see the surface of the star frozen in time at the instant where its collapse takes it to the Schwarzschild radius.[31] "

Time emerges from entanglement as might gravity according to some authors.
Title: Re: What's a black hole made of?
Post by: evan_au on 06/10/2018 22:41:20
Quote from: Bill S
the infalling object ... is gradually vanishing
The infalling object is traveling at something like 30% of the speed of light by the time it reaches the event horizon (or would have reached it, if it continued coasting along at this same leisurely speed).

The light of the infalling object is snuffed out in microseconds, by being red-shifted into oblivion.
You may be able to see it a few microseconds longer if you set off an atomic bomb at the right moment - the gamma rays would be red-shifted into the visible range for an instant...
Title: Re: What's a black hole made of?
Post by: PmbPhy on 06/10/2018 23:12:50
While your quote is apparently accurate in the RF of the distant observer; would it not be true that in its own RF, the infalling matter not only reaches, but crosses the event horizon?
Absolutely!
Title: Re: What's a black hole made of?
Post by: Butch on 07/10/2018 00:40:57
A black hole can be made up of very normal matter, it depends on the size of the black hole. The super massive black hole thought to be at the center of the milky way should have an average mass density about the same as water on Earth. All bodies have a Schwarzchild radius, in those that are not black holes this radius is smaller than that of the body itself.
Title: Re: What's a black hole made of?
Post by: Butch on 07/10/2018 00:49:16
The same thing applies to all matter because all matter is slower than light.
See Eq 10.

Only in reference to the observer, a object traveling faster than c relative to the observer, could not be observed, referenced to the object itself it would not be moving at all. Many are mislead by the idea that the gravity of a black hole rips objects asunder. This is not known, time and space dilation becomes very tricky ground to tread upon.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 07/10/2018 01:10:39
A black hole can be made up of very normal matter, it depends on the size of the black hole. The super massive black hole thought to be at the center of the milky way should have an average mass density about the same as water on Earth.
All of that is wrong. Where did you get that idea from?
Title: Re: What's a black hole made of?
Post by: guest45734 on 07/10/2018 09:32:36
The super massive black hole thought to be at the center of the milky way should have an average mass density about the same as water on Earth.

There are more than one black hole in our milkyway https://www.telegraph.co.uk/science/2018/04/04/tens-thousands-black-holes-exist-center-milky-way-scientists/ and more than meets the eye in our universe http://hubblesite.org/explore_astronomy/black_holes/encyc_mod3_q7.html
Title: Re: What's a black hole made of?
Post by: guest45734 on 07/10/2018 09:49:16
The inflationary universe is but one of many theories ref the beginnings of the universe. Nikodem Popolawski a theoretical physicist, has theorized we could live inside a black hole and that ER bridges and other universes might exist.  https://en.wikipedia.org/wiki/Nikodem_Popławski.

Understanding exactly what space is and how gravity works at the quantum level is key to knowing what goes on inside a Black hole. Popalawski does not adhere to Hoyles ideas of matter constantly coming into existence or the inflationary universe.

Popalawski theorizes big bounces are the source of matter in the universe, he is a prolific worker https://arxiv.org/a/poplawski_n_1.html the paper of interest here is this https://arxiv.org/pdf/1801.08076.pdf
Title: Re: What's a black hole made of?
Post by: evan_au on 07/10/2018 10:11:16
Quote from: Butch
The super massive black hole thought to be at the center of the milky way should have an average mass density about the same as water on Earth.
Quote from: PmbPhy
All of that is wrong. Where did you get that idea from?

A back-of-the-envelope calculation suggests:
- Mass of the Milky Way's supermassive black hole: 8.2x1036 kg
- Schwarzchild radius: 1.2x1010m
- Density: 4600 tonnes/cubic meter

This is a lot higher than Earth's density of 5 tonnes/cubic meter, or water at 1 tonne/cubic meter.

Quote from: Wikipedia
the average density of a SMBH (defined as the mass of the black hole divided by the volume within its Schwarzschild radius) can be less than the density of water in the case of some SMBHs. This is because the Schwarzschild radius is directly proportional to mass, while density is inversely proportional to the volume.
- It's just that the one at the center of our galaxy is only around 4 million times the mass of the Sun.
- The M87 galaxy is estimated to have a black hole about 6 billion times the mass of the Sun
Title: Re: What's a black hole made of?
Post by: Bill S on 07/10/2018 11:09:06
Quote from: dead cat
......to an outside observer of our universe time does not exist, it only exists in our reference frame.

Now, there's an interesting comment.

To some extent, I agree, but in your view, if there were observers outside our Universe, how could they do any observing if time didn't exist?
Title: Re: What's a black hole made of?
Post by: Bill S on 07/10/2018 11:23:47
Quote from: Evan_au
The light of the infalling object is snuffed out in microseconds, by being red-shifted into oblivion.

So, the idea that an outside observer would continue to see objects, indefinitely, at the event horizon is not right?

How long might it take for the light to be red-shifted beyond microwave radiation? 
Title: Re: What's a black hole made of?
Post by: PmbPhy on 07/10/2018 12:50:54
Quote from: dead cat
......to an outside observer of our universe time does not exist, it only exists in our reference frame.

Now, there's an interesting comment.

To some extent, I agree, but in your view, if there were observers outside our Universe, how could they do any observing if time didn't exist?

He's totally wrong. To be an observer one must observe. That's something that occurs in time.

There's the concept of parallel universes and in those universes there's no reason to assume there's no time. In fact if those universes have the same property as ours then time does indeed exist for them.
Title: Re: What's a black hole made of?
Post by: Halc on 07/10/2018 12:58:31
A black hole can be made up of very normal matter, it depends on the size of the black hole. The super massive black hole thought to be at the center of the milky way should have an average mass density about the same as water on Earth.
All of that is wrong. Where did you get that idea from?
It cannot be made of normal matter.  That part is wrong.  Normal matter of that mass cannot support its own weight, and breaks down even before the black hole forms.
The density part can be as low as (or much lower than) water.  I'm getting conflicting figures for the average density (total mass/volume inside the Schwarzschild radius) of our galactic black hole that both higher and lower than water.
Title: Re: What's a black hole made of?
Post by: Halc on 07/10/2018 13:13:17
Quote from: dead cat
......to an outside observer of our universe time does not exist, it only exists in our reference frame.
[PmbPhy is] totally wrong. To be an observer one must observe. That's something that occurs in time.

There's the concept of parallel universes and in those universes there's no reason to assume there's no time. In fact if those universes have the same property as ours then time does indeed exist for them.
I have to agree with dead cat here.  A human inside a large black hole is an observer (inside a small one, he's a smear), and effectively exits the universe when crossing the event horizon.  If he's looking backwards, he sees the stars wink out in a rush of red-shift and from that point on, he cannot see anything from the outside.  Sure, light still falls in, but it cannot reach our observer, who very much is still observing and exists in a time, even if that time is now bent in a different direction.

From the perspective of the rest of the universe, the falling observer never left it.  Glued on the surface of the black hole, yes: Not by slowing of velocity, but just not entering it yet as the event of him crossing over is in the future of the current moment of the distant observer, in the frame of that distant observer.  Such is the weirdness of bent space it seems.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 07/10/2018 13:28:44
Quote from: dead cat
......to an outside observer of our universe time does not exist, it only exists in our reference frame.
[PmbPhy is] totally wrong. To be an observer one must observe. That's something that occurs in time.

There's the concept of parallel universes and in those universes there's no reason to assume there's no time. In fact if those universes have the same property as ours then time does indeed exist for them.
I have to agree with dead cat here.  A human inside a large black hole is an observer (inside a small one, he's a smear), and effectively exits the universe when crossing the event horizon.  If he's looking backwards, he sees the stars wink out in a rush of red-shift and from that point on, he cannot see anything from the outside.  Sure, light still falls in, but it cannot reach our observer, who very much is still observing and exists in a time, even if that time is now bent in a different direction.

From the perspective of the rest of the universe, the falling observer never left it.  Glued on the surface of the black hole, yes: Not by slowing of velocity, but just not entering it yet as the event of him crossing over is in the future of the current moment of the distant observer, in the frame of that distant observer.  Such is the weirdness of bent space it seems.
He said "to an outside observer of our universe time does not exist". I didn't realize he was talking about the inside of a black hole. One doesn't call that a universe. It should say "our portion of the universe" or something so people like me don't get confused. Lol.  And its wrong to claim that time doesn't exist because it does. Outside observers simply have no access to it and they also can't see inside the black hole to verify their claim is true or not.

Messy stuff.

RE - "Not by slowing of velocity..." - That's wrong. All objects slow down and are redshifted to the extent they can't be seen. Even light slows down in a gravitational field and so too for photons moving towards the black hole.
Title: Re: What's a black hole made of?
Post by: geordief on 07/10/2018 14:23:54
Even light slows down in a gravitational field and so too for photons moving towards the black hole.
Does it slow down in a continuous way ?(ie if the gravitation increases it slows down more and more until the gravItational force is equal to that of a black hole and its speed is zero: do more powerful black holes make its velocity reverse?)

At what stage do photons (=em waves?) cease to exist in a BH?
Title: Re: What's a black hole made of?
Post by: Bill S on 07/10/2018 15:08:08
Quote from: dead-cat
  What is observed and what is happening is all relative, to an outside observer of our universe time does not exist, it only exists in our reference frame.

I, too, interpreted this as meaning outside our Universe, rather than inside a BH.  Only Dead-cat can tell us what the intended meaning was.

Quote from: Halc
A human inside a large black hole is an observer (inside a small one, he's a smear), and effectively exits the universe when crossing the event horizon.

I’m going to sidestep the question of what constitutes an observer.

However, I cannot agree that an observer exits the Universe “when crossing the event horizon”.  The BH is in the Universe, so, surely, its contents are also in the Universe.

One might subscribe to the view that a BH “singularity” is a gate (or bridge) to another universe; but even if that were the case, the observer would have to pass through that gate to exit the Universe, so would, arguably, no longer be in the BH.
Title: Re: What's a black hole made of?
Post by: guest45734 on 07/10/2018 19:45:56
Even light slows down in a gravitational field and so too for photons moving towards the black hole.
Does it slow down in a continuous way ?(ie if the gravitation increases it slows down more and more until the gravItational force is equal to that of a black hole and its speed is zero: do more powerful black holes make its velocity reverse?) 

At what stage do photons (=em waves?) cease to exist in a BH?


Light speed is a universal constant it does not vary or slow. A photon loses energy escaping a gravitational field. A photon ceases to exist when the frequency is 0 ie E = hf 
Title: Re: What's a black hole made of?
Post by: guest46746 on 07/10/2018 20:26:11
Is a BH empty? If it rotates, the answer needs to be no. Mass is required for rotation. So, does a BH illuminate? No, illumination requires photonic energy. So, if a BH is not void of mass and it doesnot illuminate, it must be composed of subatomic particles that arenot congealed in a structure. This would emmulate the condition directly after the big bang, where subatomic particle mass was abundant but due to the highly energetic environment formation of structure was impeded. Imagine an environment where massless and near massless particles are compressed into a quantum state of sharing the same space/time local, 2D. Now return to the big bang, where the this primordial soup of subatomic particle stewed until a time where a cooling transpired and the congealing took place by way of gravity. Under the auspicious of this cooling, a shrinking transpired, this shrinking initiated a motion, a movement. As there was no impediment to the "initial motion" it went into a free fall of rotation. The ensuing accumulation of free fall rotation velocity produced a chiralty gravititaional effect. This gravitational effect acted as a large tumbler, allowing the subatomic particles to engage and disengage in an infinite number of ways. Eventually, subatomic particles coupled into a Light/EM combination. This coupling, producing a light singularity became the predominant structure to emerge from the dark period.   

So, a BH rotates, it is comprised of subatomic particles that are locked in a quantum state of compressed engagement. This state is where quantum has multiple subatomic particles compressed into and sharing a single local of time/space. The closest analogy to visualize this quantum state is to imagine a 2D environment surround by a 3D environment. The BH surrounded by a Galaxy,  Does this preclude a BH as a different dimension? No. So, how does this relate to the Big Bang? Think of the BH has a localized version model the big bang. The black hole, is a singularity, it is comprised of unattached subatomic particles, It requires a catalyst to release it's potential. The Hawkings theory leaves open the possibilty of a strong gravitional field creating a particle and an antiparticle pair at the event hole horizon. If the anti-particle were to be separated into the BH from it's particle counterpart prior to annilation, it is possible that the anti-particle could be the catalyst for a BH gamma ray burst. lol

What is constantly being demonstrated in nature, is that property attributes of a child systems are legacies of a parent system. Although the model of the Big Bang and a Black Hole may differ in regards to their individual catalyst,
and their respective releases of energy, their results are comparative as to generative abilities.  lol
Title: Re: What's a black hole made of?
Post by: Halc on 07/10/2018 20:34:11
He said "to an outside observer of our universe time does not exist". I didn't realize he was talking about the inside of a black hole. One doesn't call that a universe.
Well, I called the outside of it a universe, and our observer severs all connection with that.  We on the outside and him on the inside can exchange no information.  That sounds like separate worlds at least, albeit not separate universes.

Quote
It should say "our portion of the universe" or something so people like me don't get confused. Lol.  And its wrong to claim that time doesn't exist because it does.
I said "who very much is still observing and exists in a time", so I'm not sure who claimed time not existing there.  A different dimension is time, but there is still the 3 spatial and 1 time dimension to it all.


Quote
RE - "Not by slowing of velocity..." - That's wrong. All objects slow down and are redshifted to the extent they can't be seen. Even light slows down in a gravitational field and so too for photons moving towards the black hole.
Intuitions are funny here, but you're right I think.  I unrealistically envision fast things approaching light speed and they never hit c but they don't slow down either.  But he event horizon is super-bent space and the rules there are different.  Yes, at the singularity, things stop in our external reference. Hawking was worried about preservation of information when things fall irretrievably into a black hole, but all the information pasting to the surface is not lost information.
Title: Re: What's a black hole made of?
Post by: evan_au on 07/10/2018 22:29:18
Quote from: Halc
(A Black Hole) cannot be made of normal matter.  That part is wrong.  Normal matter of that mass cannot support its own weight, and breaks down even before the black hole forms.
I think it is just a matter of grammatical tense here.
- We see mechanisms that form black holes from normal matter when a star implodes and/or explodes.
- However, once this matter approaches the singularity, normal matter should be torn apart - it's not clear what the components would be (eg would they be outside the Standard Model?)
- And once it reaches the singularity, normal matter should be mashed together - it's not clear what the result would be
- But really, we can't say much about what happens inside the event horizon of a black hole

Quote from: Pesqueira
Is a BH empty? If it rotates, the answer needs to be no.
We expect that most black holes will form with the angular momentum of their parent star, accretion disk or galaxy.
It is theoretically possible for a black hole to have near-zero angular momentum:
- If there was a merger of two black holes with opposite and equal angular momentum.
- Or transiently, if the black hole was tearing off the atmosphere of a nearby star which was orbiting in the opposite direction to the direction of black hole rotation.
- But I expect that most black holes would have considerable angular momentum

Quote
The black hole, is a singularity, it is comprised of unattached subatomic particles
A black hole singularity in general relativity is where all of the particles end up at a single point; all paths entering the event horizon end up at the singularity.

Some theories of Quantum Gravity may allow some quantum fuzziness about the "single point".

But Quantum Gravity is not yet sufficiently mature to assert that "it must be composed of subatomic particles that are not congealed in a structure".

Quote
a chiralty gravitational effect
Gravitational waves are polarized.

Once 3 gravitational wave observatories were online, it was possible to detect the polarization of gravitational waves.

The first one was: https://en.wikipedia.org/wiki/GW170814

But I don't understand  "a chiralty gravitational effect".
Title: Re: What's a black hole made of?
Post by: guest46746 on 07/10/2018 23:48:22
But I don't understand  "a chiralty gravitational effect".


Chirality gravitational effect, is an innate effect that is completely random and permanently imbued at the moment of it's initiation. Gravity was the first fundamental force. At the first rotation of the Light singularity, a left handed chirality for it's particle nature was established. . If the EM/Light singularity had rotated to the right our Universe would have been a righthanded chirality Universe. The nature of electromagnetism is that once the direction of force has been established only a a stronger force can reverse it's direction. We live in a fermion Universe where fermion particles spin to the left and anti-particles spin to the right. The overwhelming nature of our Universe consist of fermion particles. This was determined at the foundation and was a completely random event. lol
Title: Re: What's a black hole made of?
Post by: guest46746 on 08/10/2018 01:40:04
A BH is the proof of Light at rest = 0. A BH has a "below the well" energy of -0. It exists has a 1D and 2D structure and therefore not restricted from possessing a -0 "below the well" energy. It acts as a gravitational monopole singularity. It does not have a time/space 3D structure, therefore it is a null location, it is a dormant singularity incapable of activity without a catalyst. It has not the plasticity of gravitational or light waves. It is monolithic in purpose, collect and converse Light. The BH is a centralize quantum structure with a 1D singularity gravitational point. As a quantum structure it cannot contain 3D fermion mass particles which are under the standard physics limitation of two particles cannot share the same space/time location. It can however, contain 2D low mass and massless particles that have no such space/time restrictions. Although dormant, a catalyst can promote a BH release of gamma rays energy. The trigger mechanism for this release is most likely an external catalyst that activates the 2D particles into active light photons which causes an cascading avalanche of energy out of the BH. This expulsion of energy ignites the stores of frozen Light at the Event Horizon, resulting in a Gamma ray burst. lol   
Title: Re: What's a black hole made of?
Post by: PmbPhy on 08/10/2018 02:49:12
A BH is the proof of Light at rest = 0.
What does the "= 0" mean? Light can never be a rest, even near a BH.
Title: Re: What's a black hole made of?
Post by: Halc on 08/10/2018 03:07:34
I think it is just a matter of grammatical tense here.
- We see mechanisms that form black holes from normal matter when a star implodes and/or explodes.
- However, once this matter approaches the singularity, normal matter should be torn apart - it's not clear what the components would be (eg would they be outside the Standard Model?)
- And once it reaches the singularity, normal matter should be mashed together - it's not clear what the result would be
- But really, we can't say much about what happens inside the event horizon of a black hole
Agree to all of that.  The contents are the same stuff as on the outside, but not likely in any form we've seen.
Even neutron stars are pretty much beyond empirical testing, leaving only the energy bursts to paint a picture of the structure within.
Title: Re: What's a black hole made of?
Post by: guest46746 on 08/10/2018 03:12:50
What does the "= 0" mean? Light can never be a rest, even near a BH.

Light at a BH is not traveling at the speed of light! It is not traveling at all, as it cannot escape the BH gravitational attraction. At rest it has 0 mass energy! lol
Title: Re: What's a black hole made of?
Post by: evan_au on 08/10/2018 09:06:11
Quote from: Pesqueira
Although dormant, a catalyst can promote a BH release of gamma rays energy.
By "a catalyst", do you mean a neutron star that passes close enough to be disrupted by the black hole?
- I expect that would cause quite a burst of gamma rays

But the gamma rays come from the neutron star, which is outside the black hole's event horizon, not from within the black hole itself.

And the definition of a catalyst is that it is not disrupted by the reaction that it catalyzes. Definitely not the case here!

Or are you referring to the hypothesis that the singularity at the center of a black hole could be the origin of a separate Big Bang, in a universe contained within the black hole? In that case, the gamma rays would not be emitted outside the event horizon in our universe, but into the new universe within the black hole.
See: https://en.wikipedia.org/wiki/Black_hole_cosmology

I know that evidence about Black Holes is hard to obtain at this point in time, but please provide some evidence for your theories.
Title: Re: What's a black hole made of?
Post by: jarvisss on 08/10/2018 09:18:23
Hi Jarvisss, welcome.

You might think differently when you are 59. :)

Who knows :) Now it looks as a very attractive idea
Title: Re: What's a black hole made of?
Post by: jeffreyH on 08/10/2018 13:48:44
I would hazard a guess that you would be dead before you reached your destination.
Only the little ones kill you before you get there.  One can cross the event horizon of a big one without even noticing.  OK, it will still kill you soon enough, but a similar death to being spun at a fatal RPM, which isn't the sort of way I'd choose to go out given a choice.

Answer to the OP then:  It would then be made of you!  You are what you eat.

What I meant was you wouldn't live long enough to reach a black hole if traveling from earth.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 08/10/2018 18:12:20
What does the "= 0" mean? Light can never be a rest, even near a BH.

Light at a BH is not traveling at the speed of light! It is not traveling at all, as it cannot escape the BH gravitational attraction. At rest it has 0 mass energy! lol
That is incorrect. Light is always moving when going into a black hole. It's merely slowing down. A particle like a photon can always be moving towards the event horizon and still never get there. Its sort of like Zeno's paradox. First its moving at c, then later at c/2 then c/4 then c/5 ....... At no time in that sequence is the photon at rest.
Title: Re: What's a black hole made of?
Post by: Halc on 08/10/2018 19:30:30
I would hazard a guess that you would be dead before you reached your destination.
Only the little ones kill you before you get there.  One can cross the event horizon of a big one without even noticing. 
What I meant was you wouldn't live long enough to reach a black hole if traveling from earth.
Maybe I have a really fast ship.  I can get anywhere I want if I go fast enough.  Straight into Sagittarius A is within reach.  I'll still be alive when I get there even if everybody I left behind is long dead.  Not 30000 years dead either.  Weird (but not very interesting) way to achieve immortality.
Title: Re: What's a black hole made of?
Post by: Halc on 08/10/2018 19:35:39
Light is always moving when going into a black hole. It's merely slowing down. A particle like a photon can always be moving towards the event horizon and still never get there. Its sort of like Zeno's paradox. First its moving at c, then later at c/2 then c/4 then c/5 ....... At no time in that sequence is the photon at rest.
Isn't it always going at c?  It's just that time dilates to 'stopped' at the event horizon, at least from an external POV.  It is a singularity, where light moves 0 meters in 0 seconds, which isn't stopped at all.  The speed is just undefined there, but c everywhere else.
Title: Re: What's a black hole made of?
Post by: geordief on 08/10/2018 19:41:21
That is incorrect. Light is always moving when going into a black hole. It's merely slowing down. A particle like a photon can always be moving towards the event horizon and still never get there. Its sort of like Zeno's paradox. First its moving at c, then later at c/2 then c/4 then c/5 ....... At no time in that sequence is the photon at res
Does it follow from that that light slows down  (from an observer's perspective) whenever it goes into any gravitational well (eg the Sun) ?
Title: Re: What's a black hole made of?
Post by: guest46746 on 08/10/2018 21:58:51
When traveling at the speed of light, time slows down and may even stop, the environment is at essentially at a 0 rest state. Now imagine an environment that is comprised of solely radiant energy. EM/Light and Gravity.
The environment is completely contained. Everything in regards to its characteristic attributes has been made homogenous.Gravitaional attraction is unaltered across the expanse of the containment, this is due to a monopole singularity, it has no wave structure only presence. Light trapped by this monopole's singularity gravitational force also is without a wave dynamic, because of the monolithic nature of the monopoles gravity (no waves). So, with no Light waves, there becomes no differentials between objects moving at different velocities passed each other, this eliminates time. With time eliminatated there is no measurement of distance, with no measurement of distance there can be no space.

This describes both a quantum environment and a BH! …… doing this buck naked! well almost! lol
Title: Re: What's a black hole made of?
Post by: yor_on on 09/10/2018 07:39:59
Another interesting question would be if light ever could have a geodesic towards a event horizon. After all, the closer you get to a possible 'center' the closer to that would the geodesic path be, if now something could be 'reflected'? And in the case where a center would be every/thing/where inside a event horizon the question wouldn't even exist, would it?

And I think Pete was thinking of a 'photon' from a far away observers perspective there.
=

Although maybe not? You can argue that 'photon' slows down by gravity, myself I think of it as following a geodesic path (using main stream physics) which hopefully keep it at 'c'. When one argue that is slows down, it should be relative a distance locally measured as well as ones local wrist watch,
Title: Re: What's a black hole made of?
Post by: evan_au on 09/10/2018 10:04:07
Quote from: Pesequeira
Light trapped by this monopole's singularity gravitational force also is without a wave dynamic, because of the monolithic nature of the monopoles gravity (no waves). So, with no Light waves...
This post seems to be suggesting that there can be no light waves within a black hole (ie no light and no photons)?

One tool used by physicists is the "light cone", a volume of space within which light could propagate in a given time.

And physicists are happy to draw light cones at any position outside a black hole's event horizon - and even extrapolate across the event horizon to predict what might happen inside the event horizon.

The results within the event horizon are weird to our eyes - for example, time and space axes appear to be interchanged.
- However, there is nothing that prevents light from propagating - providing it propagates towards the singularity at the center of the black hole
See: https://en.wikipedia.org/wiki/Light_cone#In_general_relativity
Title: Re: What's a black hole made of?
Post by: PmbPhy on 09/10/2018 11:07:27
Quote from: Pesequeira
Light trapped by this monopole's singularity gravitational force also is without a wave dynamic, because of the monolithic nature of the monopoles gravity (no waves). So, with no Light waves...
This post seems to be suggesting that there can be no light waves within a black hole (ie no light and no photons)?

One tool used by physicists is the "light cone", a volume of space within which light could propagate in a given time.

And physicists are happy to draw light cones at any position outside a black hole's event horizon - and even extrapolate across the event horizon to predict what might happen inside the event horizon.

The results within the event horizon are weird to our eyes - for example, time and space axes appear to be interchanged.
- However, there is nothing that prevents light from propagating - providing it propagates towards the singularity at the center of the black hole
See: https://en.wikipedia.org/wiki/Light_cone#In_general_relativity
Bee - eeee - ay - yutiful!
Title: Re: What's a black hole made of?
Post by: PmbPhy on 09/10/2018 11:12:19
That is incorrect. Light is always moving when going into a black hole. It's merely slowing down. A particle like a photon can always be moving towards the event horizon and still never get there. Its sort of like Zeno's paradox. First its moving at c, then later at c/2 then c/4 then c/5 ....... At no time in that sequence is the photon at res
Does it follow from that that light slows down  (from an observer's perspective) whenever it goes into any gravitational well (eg the Sun) ?

The coordinate speed of light does slow down in a gravitational field. Einstein showed this in is 1911 paper.

The proof is on my website here: http://www.newenglandphysics.org/physics_world/gr/c_in_gfield.htm

Note the references at bottom of page. This slowing down of light was demonstrated by Irwin Shapiro in the 60's.
Title: Re: What's a black hole made of?
Post by: Bill S on 09/10/2018 11:14:11
Quote from: Pete
That is incorrect. Light is always moving when going into a black hole. It's merely slowing down. A particle like a photon can always be moving towards the event horizon and still never get there. Its sort of like Zeno's paradox. First its moving at c, then later at c/2 then c/4 then c/5 ....... At no time in that sequence is the photon at rest.

Quote from: yor_on
And I think Pete was thinking of a 'photon' from a far away observers perspective there.

Although maybe not? You can argue that 'photon' slows down by gravity, myself I think of it as following a geodesic path (using main stream physics) which hopefully keep it at 'c'. When one argue that is slows down, it should be relative a distance locally measured as well as ones local wrist watch,

I’ve got another example of Zeno’s paradox.  The nearer I come to grasping these concepts, the more slowly I reach any sort of conclusion. 😊

Let’s see if I’ve grasped this.

An observer, falling into a BH, crosses the event horizon without incident and is then inside the BH.
A distant observer sees the infalling body as slowing to a standstill at the event horizon.

A photon, falling into a BH, crosses the event horizon without incident and is then inside the BH.
A distant observer sees the infalling photon as slowing, and never reaching the event horizon.

So, an assertion such as “A particle like a photon can always be moving towards the event horizon and still never get there.” Applies only to the RF of the distant observer.  In its own RF (if it could be said to have one), or in the RF of the BH, the photon would cross the event horizon without hesitation.

Because relativity tells us that every RF has as much right as any other to be considered as “real”, the photon crosses the event horizon, and does not cross the event horizon; and both of these scenarios exist, physically, in our Universe.

Am I getting anywhere, or does Zeno still rule?
Title: Re: What's a black hole made of?
Post by: Bill S on 09/10/2018 11:24:05
Pete, my post crossed over with yours.  I followed your link and, as usual when I look at your maths, I was full of admiration, but lacking in understanding.  I’m not sure if it throws any light on my last question, or not. 

Dealing with a mathematical ignoramus must be frustrating, but I know from the past that you have patience.
Title: Re: What's a black hole made of?
Post by: Butch on 09/10/2018 13:52:58
All of that is wrong. Where did you get that idea from?
I will see if I can find a reputable link, in the meantime can you explain why you believe it to be wrong?

This should suffice!
https://www.astro.umd.edu/~miller/poster1.html
Title: Re: What's a black hole made of?
Post by: Butch on 09/10/2018 13:57:18
That is incorrect. Light is always moving when going into a black hole. It's merely slowing down. A particle like a photon can always be moving towards the event horizon and still never get there. Its sort of like Zeno's paradox. First its moving at c, then later at c/2 then c/4 then c/5 ....... At no time in that sequence is the photon at rest.
It does not slow down, it only appears so to an outside observer, black holes are really not that mysterious, they are simply bodies with an escape velocity greater than c.
Title: Re: What's a black hole made of?
Post by: evan_au on 09/10/2018 21:29:56
Quote from: Bill S
So, an assertion such as “A particle like a photon can always be moving towards the event horizon and still never get there.” Applies only to the RF of the distant observer.  In its own RF (if it could be said to have one), or in the RF of the BH, the photon would cross the event horizon without hesitation.
We start splitting hairs when we start talking about the behavior of a single photon as seen by different observers...

A single photon may cross the event horizon and enter the black hole (in which case the distant observer doesn't see it at all)
- Or a single photon may slingshot around the black hole, reversing direction so the distant observer can see it - but it does not enter the black hole.

I suggest that these thought experiments about things entering black holes are best described in the context of an observer falling into a black hole, who carries a beacon which is emitting photons in all directions. That way, you can talk about the viewpoint of the infalling observer, and the viewpoint of the distant observer, without having to divide a single photon into 2 parts traveling in opposite directions...
Title: Re: What's a black hole made of?
Post by: guest46746 on 10/10/2018 00:24:48
Light trapped by this monopole's singularity gravitational force also is without a wave dynamic, because of the monolithic nature of the monopoles gravity (no waves). So, with no Light waves...This post seems to be suggesting that there can be no light waves within a black hole (ie no light and no photons)?One tool used by physicists is the "light cone", a volume of space within which light could propagate in a given time.And physicists are happy to draw light cones at any position outside a black hole's event horizon - and even extrapolate across the event horizon to predict what might happen inside the event horizon.The results within the event horizon are weird to our eyes - for example, time and space axes appear to be interchanged.- However, there is nothing that prevents light from propagating - providing it propagates towards the singularity at the center of the black hole

If you except that Light has a dual nature of wave and particle. You must question whether Light must be in a wave form within the gravitational force of a BH.  A vacuum is void of matter. 


"The photon has zero rest mass and always moves at the speed of light within a vacuum".


Is the area within a BH's gravitational force a vacuum? No. I would say that it is a densely compressed region of photonic energy sharing the same quantum time/space local. Photons becoming particles, forced by the BH's gravity to share the same quantum space/time location. At a point, this compression becomes finite to the point of creating actual Light mass, Light particle duality. Once Light achieves particle mass it no longer is capable of traveling at the speed of light, as it inversely increases it density it regards to velocity. Particle density blocks light. The active region surrounding a BH is immerse and continually growing. Light becomes visible when it hits mass. The area of visible Light around a BH is again immerse. The area of a BH is relatively microscopic compared to the outer regions of it's BH gravity. If light inside the BH's gravitational force was indeed traveling at the speed of light, the immerse area we see surrounding it would not be reflecting the incoming Light that we observe on the outside. If Light in the gravitational field of the BH was indeed moving at the speed of light, we would actually be seeing empty space  all the way to the BH's Event Horizon. But we don't !  lol.


Title: Re: What's a black hole made of?
Post by: evan_au on 10/10/2018 10:30:17
Quote from: Pesqueira
we would actually be seeing empty space  all the way to the BH's Event Horizon. But we don't !
In fact, at the time of writing, we (the public) have not seen a black hole at all, down to the event horizon or not.

However, over the past year or so, the Event Horizon Radiotelescope has been trying to image the black hole at the center of our galaxy. They have been crunching the numbers for months now, but I haven't heard an announcement, or seen an actual image.
See: https://en.wikipedia.org/wiki/Event_Horizon_Telescope
Watch this space!

Quote
Is the area within a BH's gravitational force a vacuum?
The gravitational field of a black hole extends "to infinity". Most of this volume is a vacuum.

A black hole with a stellar companion will draw in gas to form an accretion disk. But the accretion disk is a fairly flat pancake, leaving most of the surrounding volume as a pretty good vacuum.

If you mean the singularity is not a vacuum, I would agree with you. But this is a miniscule volume at the center of the black hole.

Quote
At a point (within a black hole), this compression becomes finite to the point of creating ... Light particle duality
You don't need a black hole to create light particle/wave duality. You can demonstrate this at atmospheric pressure - or even in a vacuum chamber.

Quote
The area of visible Light around a BH is again immerse.
Are you talking about the luminous region of a black hole's accretion disk?
Nothing else about a stellar-mass black hole is visible (unless you can measure Hawking radiation with an effective black-body temperature of nanoKelvins).
See: https://en.wikipedia.org/wiki/Accretion_disk
Title: Re: What's a black hole made of?
Post by: Halc on 10/10/2018 13:22:48
Nothing else about a stellar-mass black hole is visible (unless you can measure Hawking radiation with an effective black-body temperature of nanoKelvins).
Even Hawking radiation originates outside the black hole, not from inside it.
The particles of the radiation come from gravitational energy, which is the only sort of energy that escapes and thus might reduce the mass of a black hole, so in that sense, it is the black hole itself emitting something, even if it changes form immediately beyond the event horizon.
Title: Re: What's a black hole made of?
Post by: Bill S on 10/10/2018 14:19:02
Quote from: Evan
We start splitting hairs when we start talking about the behavior of a single photon as seen by different observers...

It’s easy to slip into talking about the “behaviour” if a photon, but, as I understand it, the only behaviour a photon exhibits is travelling.  Observation involves interaction, and interaction causes a photon to cease to be a photon.  The same must apply to a collection of photons. (?)
Title: Re: What's a black hole made of?
Post by: guest46746 on 10/10/2018 14:27:41
QuoteIs the area within a BH's gravitational force a vacuum? The gravitational field of a black hole extends "to infinity". Most of this volume is a vacuum.

The BH has a finite beginning even if it is only a point. Hawking's believed it eventually evaporates, The BH gravitational field extending "to infinity" ? That would require it to extend beyond our Universe. 
Title: Re: What's a black hole made of?
Post by: guest46746 on 10/10/2018 14:30:58
QuoteAt a point (within a black hole), this compression becomes finite to the point of creating ... Light particle dualityYou don't need a black hole to create light particle/wave duality. You can demonstrate this at atmospheric pressure - or even in a vacuum chamber.

Certainly, which make the likelihood of it occurring within the compression of the BH gravitational field even more prolific.
Title: Re: What's a black hole made of?
Post by: guest46746 on 10/10/2018 14:50:09
QuoteThe area of visible Light around a BH is again immerse.Are you talking about the luminous region of a black hole's accretion disk?

The illuminous region around the BH's gravitational field represents it's external boundary, this is a reflection of the incoming light striking a mass. My point was that light within the gravitational field of the BH has particle mass. This reflection is similar to what occurs on a star, The cooler substrata below the star's surface creates a barrier that the hotter corona reflect off of. During a coronal we see the cooler substrata mass. The BH's photon particle mass in it's gravitational field is too dense to travel at the speed of light.  lol
Title: Re: What's a black hole made of?
Post by: Bill S on 10/10/2018 15:16:53
Quote
The BH has a finite beginning even if it is only a point. Hawking's believed it eventually evaporates, The BH gravitational field extending "to infinity" ? That would require it to extend beyond our Universe.

Welcome to my soapbox!  :)

Actually, I don't need it any more, as far as this particular usage of "infinity" goes.  I've come to terms with the fact that it simply means a great distance, for which we can find no end, either in practice or in principle.

As far as extending beyond our Universe is concerned; that must depend on whether or not you think the Universe infinite.

Slightly different soapbox - still occupied!  :)
Title: Re: What's a black hole made of?
Post by: guest45734 on 11/10/2018 13:37:15
Dealing with a mathematical ignoramus must be frustrating, but I know from the past that you have patience.

Hi Bill My misses emailed me a paper on BH's this morning that is taking some getting my head around, so I set about googling for some explanations and stumbled across this on the NASA site, it may help a mathematical ignoramus as long as they are not a total ignoramus https://www.nasa.gov/pdf/377674main_Black_Hole_Math.pdf

The paper I was trying to get my head around is more up @PmbPhy  street on BH's. Its going to take me some time to understand what they are talking about https://arxiv.org/abs/1810.0847 Black Hole Entropy and Soft Hair.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 11/10/2018 13:55:32
Quote from: dead cat
Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?
I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?

Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911.

Do you have a reason to claim otherwise?
Title: Re: What's a black hole made of?
Post by: geordief on 11/10/2018 14:33:34
Quote from: dead cat
Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?
I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?

Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911.


Taking the piss is different from taking a piss (although you could do both at the same time)
It means "are you joking?" broadly.(with a side of "are you winding me up" or  "getting a rise"? )

Also you could use it for someone only pretending to make an effort.
Title: Re: What's a black hole made of?
Post by: guest45734 on 11/10/2018 14:49:25
I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911. Do you have a reason to claim otherwise?

Taking the piss, humourous slang for are you making fun, as Geordief states above. You had not made it clear you were talking about light, and not matter. I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.

Title: Re: What's a black hole made of?
Post by: Halc on 11/10/2018 16:14:20
I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.
Warp drive goes well over light speed so Enterprise should have no trouble with our black hole if the plot should require such.  Physics definitely takes a back seat to entertainment here.
Title: Re: What's a black hole made of?
Post by: guest45734 on 11/10/2018 16:38:22
I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.
Warp drive goes well over light speed so Enterprise should have no trouble with our black hole if the plot should require such.  Physics definitely takes a back seat to entertainment here.

Damn I thought it was a documentary :) But even if they came under the influence of a BH they would still need to accelerate to above warp speed to break lose, something they have struggled to do on many occasions. Many inferior space ships without the ability to eject the warp cores etc don't fare so well and disappear over the event horizon, sometimes maybe to other universes existing in our theoretical multiverse.

By some weird curvature of space, can an infinite universe exist as a separate entity in a multiverse, without overlapping other universes in the multiverse. If we exist inside a BH would our spacetime appear infinite but still be contained inside a BH, etc etc please dont answer this random thought provoked by Bills question on space.

Title: Re: What's a black hole made of?
Post by: PmbPhy on 11/10/2018 16:40:07
While your quote is apparently accurate in the RF of the distant observer; would it not be true that in its own RF, the infalling matter not only reaches, but crosses the event horizon?
Correct.
Title: Re: What's a black hole made of?
Post by: PmbPhy on 11/10/2018 16:45:26
I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911. Do you have a reason to claim otherwise?

Taking the piss, humourous slang for are you making fun, as Geordief states above. You had not made it clear you were talking about light, and not matter. I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.


It applies to both light and matter.
Title: Re: What's a black hole made of?
Post by: Halc on 11/10/2018 17:18:55
Many inferior space ships without the ability to eject the warp cores etc don't fare so well and disappear over the event horizon, sometimes maybe to other universes existing in our theoretical multiverse.
Don't think you want to do that.  That core is your ticket out of that hole, and ability to eject it doesn't make your ship superior in this regard.

Quote
By some weird curvature of space, can an infinite universe exist as a separate entity in a multiverse, without overlapping other universes in the multiverse.
Our world/universe (one piece of a multiverse) is not exactly infinite.  It has its own event horizon not far outside of the Hubble Sphere.  Anything beyond that doesn't exist in our world, pretty much in the same way unicorns don't exist on Earth.  They're both in a different universe, utterly causally disjoint from us, yet both part of what you're calling a multiverse.
So yea, the inside of black holes is a funny universe with negative time.  Objects within one are in our future, and so are beyond our ability to measure now, just like tomorrow cannot be measured by an experiment today.  But causality is sort of a one-way relationship with a black hole, so I can throw in a letter addressed to Bob who fell in there yesterday, but he cannot return his reply because I no longer exist to him.  That the one can act on the other makes them not really separate worlds.

Quote
If we exist inside a BH would our spacetime appear infinite but still be contained inside a BH, etc etc please dont answer this random thought provoked by Bills question on space.
I think at least two of the dimensions (the y and z I spoke of in the 'spinning' topic) are finite: You can see the back of your head if you look that way.  Light already orbits black holes well outside the event horizon, so finite space doesn't just happen within.  To escape a black hole that far out, going in those directions with maximum power will avail you not.  You have to go in the negative x direction to attempt escape.  This is counterintuitive to orbital mechanics where the best way to escape orbit is to thrust in the positive y direction.

Sorry, I ignored your request, and took a stab at this answer.
Title: Re: What's a black hole made of?
Post by: David Cooper on 11/10/2018 22:46:15
This business of things stopping at the event horizon came up before in a discussion here. If the speed of light falls to zero at the event horizon, then nothing can cross the event horizon, ever. Light and matter simply goes more and more slowly, effectively stopping, although it's never technically a complete halt.

The reason many people imagine that a space ship could cross the event horizon of a large black hole while the people inside it continue to live normally is that the lack of Newtonian time in GR (and SR) leaves the "time" dimension as the only kind of time in the model, and that provides no mechanism to allow any clocks run slow, so for the people in the space ship their clocks must keep on ticking at full speed. However, they will be systematically annihilated before they reach the event horizon because they'll actually be stuck there for countless billions of years while the black hole gradually evaporates - the mechanism behind Hawking radiation will eliminate every single piece of their matter.

It looks to me as if the only matter that can ever get into a black hole is the matter that collapses to form a black hole, and most of the material of a collapsing body will miss the party and end up sitting just outside the event horizon of the first part to become dense enough to become a black hole. Also, if multiple parts form separate black holes during the collapse of the body, those separate parts may not be able to merge because there may be material around and between them which cannot reach/cross any of the event horizons, so I predict that you'd actually end up with a set of black holes stuck together which collectively form a sphere, but which remain distinct from each other (and the same would happen with any black hole merger).

All the above is dependent on the idea that the speed of light reaches zero at the event horizon. Perhaps it only reaches zero outwards though. If it remains higher than that inwards, then there would presumably have to be a mismatch between the speed of light up vs. down at all altitudes in a gravity well. Would such a mismatch be detectable, has it been detected, and is it predicted by GR?
Title: Re: What's a black hole made of?
Post by: PmbPhy on 12/10/2018 01:32:36
There's a great book out by Nobel Laureate Kip S. Thorne called Black Holes & Time Warps: Einstein's Outrageous Legacy.

Anybody who wants to understand general relativity and black holes should own a copy of this book!
Title: Re: What's a black hole made of?
Post by: Halc on 12/10/2018 13:02:43
This business of things stopping at the event horizon came up before in a discussion here. If the speed of light falls to zero at the event horizon, then nothing can cross the event horizon, ever. Light and matter simply goes more and more slowly, effectively stopping, although it's never technically a complete halt.
I agree that we’re probably wrong about painting the picture just like this. I’ve heard that the official physics line says that things actually do fall in, but a description of how/when from the POV of various frames is typically omitted.  The book from Thorne recommended above perhaps covers this.

From my naive view, one can drop some material ‘on’ a black hole, which gets stuck when time dilates to nothing, but drop anything else and the event horizon expands just enough and swallows the earlier material. That sounds pretty wrong, but at least it gets stuff in there, and allows the original hole to form in the first place.

On another note is the observed behavior of the merger of two black holes, where one gets to observe something big fall in.  The gravity waves come slow at first but with increasing frequency, getting higher and higher until a brief ‘chirp’ at the end when the waves cease abruptly.  That’s a view from a distant frame, and yet it speeds up at the end.  If it got stuck on the surface, wouldn’t the waves slow to imperceptibility instead of speeding up?  This pattern was predicted before it was first witnessed.

On the ‘freeze’ front, I think it was Hawking that was disturbed by the seeming violation of conservation of information when things fell into a black hole, but this was solved by realizing that from any external moment in time, the information never makes its way in, and is thus not actually lost.

I’m just pointing out what I see is evidence on both sides of this fence.
Quote
The reason many people imagine that a space ship could cross the event horizon of a large black hole while the people inside it continue to live normally is that the lack of Newtonian time in GR (and SR) leaves the "time" dimension as the only kind of time in the model, and that provides no mechanism to allow any clocks run slow, so for the people in the space ship their clocks must keep on ticking at full speed. However, they will be systematically annihilated before they reach the event horizon because they'll actually be stuck there for countless billions of years while the black hole gradually evaporates - the mechanism behind Hawking radiation will eliminate every single piece of their matter.
The surviving the crossing is hypothetical.  You’re right in that the radiation there (which is only considered Hawking radiation if part of it escapes permanently) would likely explode our traveler as he compresses years of intense radiation into a millisecond.  The gravitational field inside is even more intense, and barring a description of the physics there, it is guesswork if a biological being could exist. The comment was just to point out that little black holes kill you via tidal forces before you ever get that close. The big ones need to use different means to kill you.

The part of the ship clock ticking at full speed is correct.  Except for the clock exploding in a radiation cloud, there would be no discontinuity or anything from a temporal standpoint.
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It looks to me as if the only matter that can ever get into a black hole is the matter that collapses to form a black hole, and most of the material of a collapsing body will miss the party and end up sitting just outside the event horizon of the first part to become dense enough to become a black hole. Also, if multiple parts form separate black holes during the collapse of the body, those separate parts may not be able to merge because there may be material around and between them which cannot reach/cross any of the event horizons, so I predict that you'd actually end up with a set of black holes stuck together which collectively form a sphere, but which remain distinct from each other (and the same would happen with any black hole merger).
By that logic, all black holes would be of no size, each preventing additional mass upon reaching the threshold.  For that matter, each would then immediately evaporate, preventing actual formation of black holes.

So the view of stuff getting stuck on the surface is probably wrong, at least when worded that way.  I’d appreciate if somebody more informed (perhaps the answer from the book) would chime in.
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All the above is dependent on the idea that the speed of light reaches zero at the event horizon. Perhaps it only reaches zero outwards though.
I think the answer lies on this front.  The event horizon of a BH is very much like the edge of the Hubble Sphere.  Time there is stopped relative to us and the big bang is still banging, because space itself (not just the matter) is moving away at lightspeed.  That is dilation due to relative speed, not gravity, so the analogy might not be appropriate.  I know it is invalid to apply the rules of an inertial frame over distances large enough for space to not be flat.
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If [lightspeed] remains higher than that inwards, then there would presumably have to be a mismatch between the speed of light up vs. down at all altitudes in a gravity well.
Doesn’t much matter if time is dilated to zero. Insufficient speed isn’t the problem.  Light speed going down could be 3c, but it isn’t going to help if it has no time to go anywhere.

Bottom line is I don’t know the answers.  I’m no GR expert.
Title: Re: What's a black hole made of?
Post by: guest45734 on 12/10/2018 14:16:55
There's a great book out by Nobel Laureate Kip S. Thorne called Black Holes & Time Warps: Einstein's Outrageous Legacy.

Duly ordered from Amazon https://www.amazon.com/Black-Holes-Time-Warps-Commonwealth/dp/0393312763

I think at least two of the dimensions (the y and z I spoke of in the 'spinning' topic) are finite: You can see the back of your head if you look that way.  Light already orbits black holes well outside the event horizon, so finite space doesn't just happen within.  To escape a black hole that far out, going in those directions with maximum power will avail you not.  You have to go in the negative x direction to attempt escape.  This is counterintuitive to orbital mechanics where the best way to escape orbit is to thrust in the positive y direction.Sorry, I ignored your request, and took a stab at this answer.

I disapeared into a BH where time and space did not exist and reappeared via a wormhole inside an expanding white hole in new space time, when I first thought about this. For some it is quite an explosive idea, Big Bangs and QLG :)

For objects entering a Black hole time slows, it does not accelerate. A photon can not stop moving at light speed trying to leave a BH it simply is redshifted to death and ceases to exist, before reaching the event horizon.

An ER bridge represents a Back door in BH theory. The paper on ER bridges was published one month after the paper on EPR bridges. ER and EPR are generally thought to be equivalent.

A dimension/wormhole connecting different areas/volumes of space time back to a single point inside a BH where space time does not exist is an amusing thought. Is a big bang from a singularity existing inside a BH more likely to have occured through the event horizon of the BH or via a wormhole to all points in space time (appearing perhaps as dark energy governed by HUP, I guess maybe not, best read Petes book:) )

Jean Luc Picard of the SS Enterprise did eject his warp core causing a huge explosion allowing him to escape a BH, allowing him to return to base on impulse engines only.
Title: Re: What's a black hole made of?
Post by: Colin2B on 12/10/2018 15:08:23
Quote from: dead cat
Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?
I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?
There are a few piss terms like piss-poor, and one is piss-proud which means false pride, no reason to be proud. So anyone knocking that false pride down was said to be taking the piss out of someone. It appears to have changed meaning over the years and now means making fun of, possibly because anyone knocking the false pride would tend to ridicule it. Also piss-proud has fallen out of fashion so the derivative has been left hanging.
Title: Re: What's a black hole made of?
Post by: David Cooper on 12/10/2018 18:42:20
...but drop anything else and the event horizon expands just enough and swallows the earlier material. That sounds pretty wrong, but at least it gets stuff in there, and allows the original hole to form in the first place.

If the speed of light is zero at the event horizon both outwards and inwards, any expansion of the event horizon may drive the material next to it further out rather than swallowing it, but even if it does swallow it, there is likely no further movement towards any singularity that might be in the middle. For a long time we've been given accounts of black holes (involving things falling in and joining a singularity at the centre) which were pushed as facts but which now look very dodgy indeed.

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On another note is the observed behavior of the merger of two black holes, where one gets to observe something big fall in.  The gravity waves come slow at first but with increasing frequency, getting higher and higher until a brief ‘chirp’ at the end when the waves cease abruptly.  That’s a view from a distant frame, and yet it speeds up at the end.  If it got stuck on the surface, wouldn’t the waves slow to imperceptibility instead of speeding up?  This pattern was predicted before it was first witnessed.

I was hoping that gravity waves would show us something about the merger of two singularities, revealing what can't normally be detected, but that is apparently not the case - all we get is information from that about the event horizons merging, and almost all the mass of the black holes could be stored at those event horizons rather than deeper inside.

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On the ‘freeze’ front, I think it was Hawking that was disturbed by the seeming violation of conservation of information when things fell into a black hole, but this was solved by realizing that from any external moment in time, the information never makes its way in, and is thus not actually lost.

I think he was onto something, but it's likely that most of the light and matter never makes it in either.

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Also, if multiple parts form separate black holes during the collapse of the body, those separate parts may not be able to merge because there may be material around and between them which cannot reach/cross any of the event horizons, so I predict that you'd actually end up with a set of black holes stuck together which collectively form a sphere, but which remain distinct from each other (and the same would happen with any black hole merger).
By that logic, all black holes would be of no size, each preventing additional mass upon reaching the threshold.  For that matter, each would then immediately evaporate, preventing actual formation of black holes.

The event horizons would grow as material piles up against them. It may reach sufficient density there to produce its own event horizon, adding to a pile of conglomerated black holes that don't fully merge. If that happens, there could be a permanent barrier to them evaporating because Hawking radiation might only be able to come from material that's stuck outside the outermost event horizon. There is therefore no guarantee that a mini black hole created by a particle accelerator would immediately evaporate away - it could be a one-way process which only allows it to hold station or grow. We need to prove that that isn't the case before we do anything reckless.

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If [lightspeed] remains higher than that inwards, then there would presumably have to be a mismatch between the speed of light up vs. down at all altitudes in a gravity well.
Doesn’t much matter if time is dilated to zero. Insufficient speed isn’t the problem.  Light speed going down could be 3c, but it isn’t going to help if it has no time to go anywhere.

We shouldn't take if for granted that GR or any other theory is correct. If you have a mismatch in the speed of light in opposite directions (faster down than up), then you may have some opportunity for things to continue functioning, allowing a light clock to cross an event horizon and to continue ticking while it does so. It would be good either way if we could rule that in or out, if anyone knows of any experiment that resolves the issue.
Title: Re: What's a black hole made of?
Post by: evan_au on 13/10/2018 01:17:54
Quote from: Pesqueira
The illuminous region around the BH's gravitational field represents it's external boundary
There is a region called the "photon sphere", which is outside the event horizon (at 50% greater radius). If you emitted a flash of light here, you would see a series of light echoes as photons from the flash repeatedly orbit the black hole.

Light emitted within the photon sphere eventually finds its way into the black hole.
By itself, the photon sphere does not emit any light, so you could not call this region "luminous".
However, matter in an accretion disk around a rotating black hole is subject to severe shear forces, which does emit a lot of light (including infra-red at the outer parts, and X-Rays at the inner edge).
See: https://en.wikipedia.org/wiki/Photon_sphere

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The illuminous region around the BH's gravitational field represents ... is a reflection of the incoming light striking a mass.
If there is no infalling matter (eg from a closely-orbiting companion star) then there is no mass between the photosphere and the event horizon (...if you ignore the hypothetical, microscopically thin, microwave-shifted skin of star matter that fell into the event horizon when the black hole first formed).
For a black hole that is not actively consuming matter, there is no luminous region around it.

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This reflection is similar to what occurs on a star, The cooler substrata below the star's surface creates a barrier that the hotter corona reflect off of. During a coronal (???) we see the cooler substrata mass.
I am not sure what "coronal" event you are talking about - maybe a Coronal Mass Ejection, or the Corona that is visible during an eclipse by the Moon?
But in any case, the density of the corona is so low, and the corona's total light output is so low that it is only visible from Earth's surface during a total solar eclipse. (Space telescopes can see it at other times using a coronagraph - but they don't need to battle Earth's atmosphere...)

Apart from solar eclipses, all that we see of the Sun is the lower layers of the Sun's atmosphere - the photosphere (not to be confused with the photon sphere around black holes!). We don't need to wait for some special coronal event to see it. The photosphere is not solid, and it tends to absorb light rather than reflect it.

The photosphere has almost a black body spectrum of around 5500C, overlain with fine emission and absorption lines from elements in the Sun. It does not reflect the spectrum of the corona (which has a temperature in the millions C).
See: https://en.wikipedia.org/wiki/Photosphere
Title: Re: What's a black hole made of?Excuse my dysl
Post by: guest46746 on 13/10/2018 01:43:01
 excuse my dyslexia. I sometimes can proof read and still not distinguish my thoughts from what appears on paper. I was referring to a coronal hole. The cooler substrate acting as a barrier for the hotter surface, to reflect the outpouring  of light, as in a mirror with a black backing reflecting an image, it was a bad analogy. To compare the perimeter of the BH's gravitational boundary perimeter with the light reflecting off the mass of the Earth seemed a worst analogy, as it would cause greater confusion but for visualization  it goes to much to my point,. Incoming light reflecting off the greater mass. lol
Title: Re: What's a black hole made of?
Post by: guest46746 on 13/10/2018 01:55:29
We shouldn't take if for granted that GR or any other theory is correct. If you have a mismatch in the speed of light in opposite directions (faster down than up), then you may have some opportunity for things to continue functioning, allowing a light clock to cross an event horizon and to continue ticking while it does so. It would be good either way if we could rule that in or out, if anyone knows of any experiment that resolves the issue.


As i iread this and attempted to formulate a response, the chirality of the BH came to mind. What if the chirality of the black hole was perpendicular to the lefthanded chirality of the Universe? Meaning it was not righthanded chiralty rather it's chiralty was up and down. It would operate the opposite of drawing water up a well. The draw would act as a downward pump and sucking light down a velocity enhancer. The opening and closing  creating a vacuum. lol
Title: Re: What's a black hole made of?
Post by: guest45734 on 13/10/2018 12:34:42
Is it possible all the mass of black holes exists in the event horizon, beyond which is a wormhole, where time and space do not exist as we know it. A pre big bang state.

A link for numpties to get a clue at what I am driving at http://jila.colorado.edu/~ajsh/bh/schww.html

The event horizon is clearly very hot, and decomposing matter into gamma rays as evidenced by Pulsars. The event horizon is therefore decomposing matter, and reducing the overall mass of the event horizon. 

At the Big Bang as space time expanded is not possible that holes appeared where space time did not expand.

Is it possible that these holes still exist and are what we understand to be BH's today.

Is it further possible that gravity has a maximum where virtual particles cease to exist.

Black holes exist at the centre of all galaxies, can gravitational energy be converted to matter.

Edit after some googling I came across gravitational geons, which might answer can gravitational energy be converted to matter question.
Title: Re: What's a black hole made of?
Post by: Halc on 13/10/2018 15:10:27
Black holes exist at the centre of all galaxies, can gravitational energy be converted to matter.
Gravitational energy can and does very much get converted to matter, and on the outside of the black hole no less.  In this way matter might escape. As for the large black holes, the vast majority of this generated matter falls right back into the black hole, but a significant percentage of it gets away from the small black holes, resulting in 'Hawking radiation' that permanently reduces the mass of the BH, which is why such small BHs that are no longer accreting new material will evaporate.  The big ones do as well, but at a much slower pace.

As for all galaxies having a central super-massive black hole, this may not be true.  Perhaps a galaxy small enough not to have one isn't really a galaxy at all.  There is debate about the Megellanic Clouds having one, but they probably have at least small ones of only some thousands of solar masses.  The big ones get into the billions of solar masses.  I think ours is around 4 million or so, making the Milky Way a modest galaxy on the grand scale.
Title: Re: What's a black hole made of?
Post by: guest46746 on 13/10/2018 17:29:56
Is it possible that these holes still exist and are what we understand to be BH's today. Is it further possible that gravity has a maximum where virtual particles cease to exist.

Just my initial thought as reading. Space/time exist initially as having one D and two D dimensional property. This corresponds to hypothesis of folded space.   This time/space acts as an envelope for 3D mass, it inflates as mass enters. The uniformity of inflation is imperfect and residuals points/pockets of 1D and 2D space remain intact.   These space time points/pockets not possessing 3D properties don't abide by GR. They abide by a lesser attributes.  These lesser properties don't include 3D waves in attributes, but they accommodate 3D wave principles in expansion.  So, without 3D waves to open space/time, they accelerate possibly  folding back on themselves. To time travel would mean expanding 2D space along an already folded space/time acceleration. lol. 

As far as BHs providing a path to this folded space/time acceleration,  the space between the two could theoretically be adjoined or not. If the space/time  acceleration was adhering to our 3D universe then it would seem plausible that a entry could be possible. If the space/time acceleration fold was not adhered to our 3D universe, it seems possible that the BH in all likelihood would evaporate. lol
Title: Re: What's a black hole made of?
Post by: guest46746 on 13/10/2018 17:38:57
These space time points/pockets not possessing 3D properties don't abide by GR. They abide by a lesser attributes. 

These space time points/pockets not possessing 3D properties don't abide by GR. They abide by a lesser attributes.

These points/pockets remanents could be Back Holes. These BHs could be impervious to 3D invasiveness. If so they are sealed artifacts of a monopole one and two dimensional time. lol


Title: Re: What's a black hole made of?
Post by: Bill S on 13/10/2018 20:36:52
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Space/time exist initially as having one D and two D dimensional property.

My understanding is that 1D space (n=1) is a mathematical tool, but I would be interested to know of a physical example.

Surely, in order to act as a "pocket", 2D space would actually need a third dimension, so, would not be 2D.
Title: Re: What's a black hole made of?
Post by: guest46746 on 13/10/2018 21:27:33
My understanding is that 1D space (n=1) is a mathematical tool, but I would be interested to know of a physical example.Surely, in order to act as a "pocket", 2D space would actually need a third dimension, so, would not be 2D.


A point is a physical example, theoretically a BH could be a single point making it a one dimensional singularity.

Space/time acceleration preceeds Light and/or gravitational waves as a fabric.  It travels as a 2D linear model. Imagine pre Light big bang, an acceleration of sub-elementary particles was transpiring, having no structure, the recombining period was essentially 2D. Yet, it was advancing/accelerating as time/space but w/o mass. Light eventually emerged  it did so as a product of the time/space 2D fabric. The Space/time fabric however didnot stop it's acceleration, it continued with Light constrained by its own speed of light limitation in the new 3D dimension, moving slower and in the wake of 2D acceleration. Being a product of space/time and literally tied to it's apron strings, it follows opening the faster and advancing 2D structure in a continuim fashion much like a zipper. lol

Title: Re: What's a black hole made of?
Post by: guest45734 on 14/10/2018 10:36:35
My understanding is that 1D space (n=1) is a mathematical tool, but I would be interested to know of a physical example.Surely, in order to act as a "pocket", 2D space would actually need a third dimension, so, would not be 2D.


A point is a physical example, theoretically a BH could be a single point making it a one dimensional singularity.

Space/time acceleration preceeds Light and/or gravitational waves as a fabric.  It travels as a 2D linear model. Imagine pre Light big bang, an acceleration of sub-elementary particles was transpiring, having no structure, the recombining period was essentially 2D. Yet, it was advancing/accelerating as time/space but w/o mass. Light eventually emerged  it did so as a product of the time/space 2D fabric. The Space/time fabric however didnot stop it's acceleration, it continued with Light constrained by its own speed of light limitation in the new 3D dimension, moving slower and in the wake of 2D acceleration. Being a product of space/time and literally tied to it's apron strings, it follows opening the faster and advancing 2D structure in a continuim fashion much like a zipper. lol

Ref Singularities and missing dimensions at the point of the big bang expansion of space and time. Could the inside of a BH be similar in that time ceases to exist or time stops ticking forward for an object at  the assumed singularity at the centre of a BH.

Ref time travel, time can be slowed by gravity, but it can not go backwards. It is not possible to go back in time with todays lottery numbers and influence the outcome. From that point of view time travel is pretty useless. But it is key to maintaining the accuracy of GPS systems.
Title: Re: What's a black hole made of?
Post by: jeffreyH on 14/10/2018 15:34:05

A photon, falling into a BH, crosses the event horizon without incident and is then inside the BH.
A distant observer sees the infalling photon as slowing, and never reaching the event horizon


You cannot see an infalling photon as it is moving away from you.
Title: Re: What's a black hole made of?
Post by: jeffreyH on 14/10/2018 15:59:58
It may be that the material inside a black hole is opaque to light. In the same way that the early universe was . That way gravity would never be able to accelerate anything to light speed since all particles would be impeded and not just photons. This would mean the singularity would never be reached due to the state of matter beyond the horizon. All speculatice, of course.
Title: Re: What's a black hole made of?
Post by: guest45734 on 14/10/2018 18:13:46
It may be that the material inside a black hole is opaque to light. In the same way that the early universe was . That way gravity would never be able to accelerate anything to light speed since all particles would be impeded and not just photons.

In the early universe pre big bang, space time apparently did not exist as we know it. ie space time had not yet started to expand. Space time apparently breaks down inside a black hole ie it contracts everything including space time to nothing a notional singularity. Are you saying/speculating that dimensions of space time cease to exist inside a black hole. If this is the case what happens to matter inside a BH.

Can singularities occupying zero space hold all the mass of a BH? theoretical yes realistically matter would turn into plasma then radiation bosons at least can occupy the same space as other bosons ? . BUT inside the event horizon we don't know what is happening, multiple black holes could be orbiting each other etc etc

The laws of thermodynamics must still apply, if matter is compressed it gets hot, beyond a certain level it becomes a plasma, beyond this it is broken down to fundamental particles and radiation, then what. One theory is that the centre of a BH is supported by radiation, another is that the singularity leads to a wormhole like an ER bridge and another dimension connecting seperate locations in space. 
Title: Re: What's a black hole made of?
Post by: guest46746 on 14/10/2018 18:29:27
Ref Singularities and missing dimensions at the point of the big bang expansion of space and time. Could the inside of a BH be similar in that time ceases to exist or time stops ticking forward for an object at  the assumed singularity at the centre of a BH.
B 2D is Space/Time, with acceleration it possess time and distance. Being devoid of light, it lacks 3D volume. Hope this does not confuse some! lol


New theory posting expounds on this concept further!  lol
Title: Re: What's a black hole made of?
Post by: jeffreyH on 14/10/2018 18:47:17
It was speculation so I can't back it up. Especially since information can't get out of a black hole. The concept of a black hole sounds a lot like the conditions before the big bang are said to have been. So opacity appears to be a natural assumption for the conditions inside a black hole. Along with extreme time dilation.
Title: Re: What's a black hole made of?
Post by: guest45734 on 14/10/2018 21:36:55
It was speculation so I can't back it up. Especially since information can't get out of a black hole. The concept of a black hole sounds a lot like the conditions before the big bang are said to have been. So opacity appears to be a natural assumption for the conditions inside a black hole. Along with extreme time dilation.

I realize you were speculating. Basically no one knows for sure what resides inside a Black hole or what dimensions existed before the Big Bang. I think it comes down to what dimensions exist inside a BH, how big is the singularity. Ie Could the physical size of the singularity be defined by the event horizon or a pin hole some where in the middle of the BH, in either instance the observed effects would be the same. Basically if our sun collapsed into a BH today it would not affect the way the earth orbited it. Theoretical Hawking radiation allows information to escape from the BH to the event horizon and eventually for BH's to evaporate.
Title: Re: What's a black hole made of?
Post by: Colin2B on 14/10/2018 22:52:15
Is it possible all the mass of black holes exists in the event horizon, beyond which is a wormhole, where time and space do not exist as we know it.
From our distant frame will not see the mass going into the hole, we will see it frozen in time, but in the frame of the mass time is normal and so it can in theory pass over.

A link for numpties to get a clue at what I am driving at http://jila.colorado.edu/~ajsh/bh/schww.html
Excellent website, high on my list, I often recommend it to people.
However, numpties often don’t read the caveats Prof Hamilton places on wormholes etc, as he says they are unlikely to exist, or to be very unstable if they do.

Edit after some googling I came across gravitational geons, which might answer can gravitational energy be converted to matter question.
Wheeler and others did a lot of work on this but it was inconclusive, I remember Wheeler writing that he thought it was a dead end, others think there are stability problems. Until we have an accepted quantum gravity theory all this is still new theories territory.

Title: Re: What's a black hole made of?
Post by: evan_au on 15/10/2018 10:02:00
Some speculative theories have been moved out of this mainstream thread into "Do photons, neutrinos and dark matter have a structure?", see: https://www.thenakedscientists.com/forum/index.php?topic=75083.msg555106#msg555106
...moderator