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Offline @/antic

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What is the temperature inside a Black Hole?
« on: 09/04/2012 08:12:02 »
Hi

Any ideas?



 

Offline yor_on

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Re: What is the temperature inside a Black Hole?
« Reply #1 on: 09/04/2012 10:11:26 »
You're thinking of that a compression of a mass should create a temperature in its interactions?

But when that black hole once can exist at all, all 'mass' is defined to a dimensionless point inside it as I understands it. So there are no more interactions from / in that mass, only a 'gravity'. And the spatial dimensions might become very large, as described from the inside of such a 'black hole', even 'infinite', well, depending on your mathematical definitions and what kind of black hole you envision.

If you assume that there still is some slight volume defining that mass though?
I don't know?

But if mass is a equivalence of 'energy'?
 

Offline @/antic

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Re: What is the temperature inside a Black Hole?
« Reply #2 on: 09/04/2012 20:07:06 »
Hey Yoron,

Yes, indeed, the compression of matter into a point must be accompanied by enormous amounts of friction and the kinetic energy of the matter would be transformed into heat.

I’m thinking mainly about the supermassive black holes at the centres of galaxies. Heat is dissipated through x-rays? And surely this must be correlated to the mass of the Black Hole? So, what would be the temperature of the Black Hole?

Do you think that matter is able to move into other spatial dimensions through Black Holes, and would this still be consistent with the Law of conservation of energy?

Cheers,

Atlantic
 

Offline Nizzle

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Re: What is the temperature inside a Black Hole?
« Reply #3 on: 10/04/2012 07:35:38 »
For me, a black hole is a QGP, so i'd say about tens of trillions Kelvin.
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #4 on: 10/04/2012 08:06:29 »
Realistically I believe we have very little idea of what goes on inside a black hole.  Personally I'm inclined to think that if matter is squashed out of existence but infinite gravity remains then the temperature at it's core will be essentially zero.
 

Offline syhprum

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Re: What is the temperature inside a Black Hole?
« Reply #5 on: 10/04/2012 09:18:30 »
It seems a rather meaningless question as the normal definition of temperature does not seem to apply to the insides of black holes but my guess would be the planck temperature of 1.416833 × 10^32°K
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #6 on: 10/04/2012 10:51:05 »
It seems a rather meaningless question as the normal definition of temperature does not seem to apply to the insides of black holes but my guess would be the planck temperature of 1.416833 × 10^32°K

"Current cosmological models postulate that the highest possible temperature is the Planck temperature, which has the value 1.416785(71)×1032 kelvin.[3] The Planck temperature is assumed to be the highest temperature in conventional physics because conventional physics breaks down at that temperature. Above ~1032K, particle energies become so large that there is no existing scientific theory for the behavior of matter at these energies. Gravitational forces between them would become as strong as other fundamental forces,"
http://en.wikipedia.org/wiki/Absolute_hot

Would that mean that gravity was infinite?  If so then time should stop which is what happens at absolute zero. 

So is absolute hot, the same as absolute cold?
(Imagine a line with cold at one end and hot at the other.  Now form it into a loop.)
Think I'm going to give up on this one!
 

Offline Nizzle

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Re: What is the temperature inside a Black Hole?
« Reply #7 on: 10/04/2012 11:02:59 »
It seems a rather meaningless question as the normal definition of temperature does not seem to apply to the insides of black holes but my guess would be the planck temperature of 1.416833 × 10^32°K

... which occurs at QGP :o
 

Offline yor_on

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Re: What is the temperature inside a Black Hole?
« Reply #8 on: 10/04/2012 11:33:44 »
Let us assume something falling into the event horizon, disappearing from our God like view :)

As soon as it has, assuming that the inside of a black hole have a 'space' too, it should follow a geodesic. Now, when following a 'accelerating gravitational' geodesic, does the object give of heat in a empty space?

Not that I know. So as long as the geodesics are unique for each object infalling and they don't intersect in time and space there should be no radiation, as I think of it now?

Any x-rays etc, we see are phenomena happening outside a event horizon, most of them due to black holes rotating incredibly close to lights speed in a vacuum. I don't think we cataloged any Black hole, yet, that's not rotating? Doesn't mean there can't be though.

And a Black Hole is not supposed to be 'warmer' than the surrounding 'space' outside it, as I understands it, it is supposed to be colder actually :)
 

Offline yor_on

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Re: What is the temperature inside a Black Hole?
« Reply #9 on: 10/04/2012 11:45:34 »
As for if the Black hole somewhere else might become a white hole?
I don't know myself.

Take a look here, follow the links to 'wormholes', and then decide for yourself :)

"Einstein collaborated with others to produce a model of a wormhole. His motivation was to model elementary particles with charge as a solution of gravitational field equations, in line with the program outlined in the paper "Do Gravitational Fields play an Important Role in the Constitution of the Elementary Particles?". These solutions cut and pasted Schwarzschild black holes to make a bridge between two patches.

If one end of a wormhole was positively charged, the other end would be negatively charged. These properties led Einstein to believe that pairs of particles and antiparticles could be described in this way."


 

Offline Nizzle

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Re: What is the temperature inside a Black Hole?
« Reply #10 on: 10/04/2012 12:05:16 »
As soon as it has, assuming that the inside of a black hole have a 'space' too, it should follow a geodesic. Now, when following a 'accelerating gravitational' geodesic, does the object give of heat in a empty space?

I think there will be multiple geodesics to follow as the object will be under such a gravitational stress that it's ripped apart. Now, if a black hole would be a ball of GQP in the centre, the temperature would be at Planck scale, at which point gravity becomes as strong as the other 3 fundamental forces. If we then look at a single atom falling into the Event Horizon, the pull on the atomic nucleus will be much harder than on the electrons, so the atomic nucleus will be absorbed in the ball of GQP well before the electrons who will eventually follow. These separations of nuclei and their electrons might give off radiation, and the collision of the nucleus with the GQP might give off radiation and the subsequent collision of the electrons with the GQP might also give off radiation. Since we're dealing with such extreme conditions, we don't even know if all of these radiations are photon based, but that it could be gluon or W or Z boson based radiation as well. All these processes could generate heat as byproduct, keeping the temperature near or at planck temperature..
 

Offline yor_on

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Re: What is the temperature inside a Black Hole?
« Reply #11 on: 10/04/2012 13:04:56 »
Yes, you're right, I ignored tidal forces. And considering those?

I still don't know which will be true. Are there 'tidal forces' inside that possibly expanded 'space'? You might want to argue that we too could be seen as 'existing' inside a 'Black Hole', or spewed out from a 'White Hole', whatever tickles ones imagination :) and whatever makes one define what a 'space(time)' is.
==

Spaghettification.
=

As for making a Quark Gluon Plasma?

I don't think the gravity is strong enough at the event horizon. Try to calculate what force you would need to rip an atom into its constituents and then tell me :) Then you just need to calculate what the gravity's potential needs to be. Maybe if you were very close to a 'center' of a Black Hole though? But if being so close?

There we might get our 'radiation' in a Big Bang :)

Pure 'energy' that (somehow) must interact to 'fuse' into 'particles' of mass.
I like that idea, although it makes little sense, as it becomes a yo-yo effect presuming something always preexisting for it to be created from. A truly 'cyclic' universe.
« Last Edit: 10/04/2012 13:47:29 by yor_on »
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #12 on: 10/04/2012 15:34:53 »
yor_on

I think a black hole at the end of our universe cycle becomes a white hole (quasar) at the start of the next.
 

Offline syhprum

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Re: What is the temperature inside a Black Hole?
« Reply #13 on: 10/04/2012 16:25:49 »
I think some Idea of temperature could be obtained by applying the consevation of energy rule assuming the the originol star that collapsed had a mass of 10^32 Kg a density of 1 and and average tempurature of 10,000 °K when compressed to QGP density the temperature would go up in proprtion.
Perhaps some more mathematical competent correspondent could refine these figures.
 

Offline yor_on

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Re: What is the temperature inside a Black Hole?
« Reply #14 on: 10/04/2012 18:00:36 »
It goes back to a question of what a rest mass should be seen as it seems? A quark has a mass, the universe prefer the quarks that can't decay into lower a mass, so up and down quarks are the preferred quarks in our universe. But in that 'center' there are no quarks as I understands it? Gluon's, on the other hand, is defined as 'bosons' similar to our photon in that there is no 'mass' to be found, even thought they create a mass in particles as they are somehow bound to them.

So that center may have a he* of a lot of bosons, but no particles of rest mass. And as the 'point' there is assumed to be dimensionless? Without a way to communicate with SpaceTime, how do they tell that there must be a 'gravity'?
« Last Edit: 10/04/2012 18:02:30 by yor_on »
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #15 on: 11/04/2012 00:55:10 »
Depends on where you look.

If you looked at the density of a black hole from inside, it would seem less inside than being an observer who was looking outside of it.
 

Offline @/antic

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Re: What is the temperature inside a Black Hole?
« Reply #16 on: 12/04/2012 11:22:55 »
Hi

Really interesting responses and lots of food for thought!!
Thanks. :)

Atlantic
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #17 on: 12/04/2012 23:49:47 »
Hi

Any ideas?

Depends on the size. Small black holes are very very hot. Large black holes are relatively cold.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #18 on: 12/04/2012 23:50:32 »
Hi

Any ideas?

Depends on the size. Small black holes are very very hot. Large black holes are relatively cold.

And from where you look, but that is very technical and I don't exactly know why I said that first.
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #19 on: 14/04/2012 06:47:09 »
"The Question

(Submitted November 11, 1997)
What is the temperature of a black hole?

The Answer

The temperature of a black hole is determined by the 'black body radiation temperature' of the radiation which comes from it. (e.g., If something is hot enough to give off bright blue light, it is hotter than something that is merely a dim red hot.)
For black holes the mass of our Sun, the radiation coming from it is so weak and so cool that the temperature is only one ten-millionth of a degree above absolute zero. This is colder than scientists could make things on Earth up until just a few years ago (and the invention of of a way to get things that cold won the Nobel prize this year). Some black holes are thought to weigh a billion times as much as the Sun, and they would be a billion times colder, far colder than what scientists have achieved on Earth.

However, even though these things are very cold, they can be surrounded by extremely hot material. As they pull gas and stars down into their gravity wells, the material rubs against itself at a good fraction of the speed of light. This heats it up to hundreds of millions of degrees. The radiation from this hot, infalling material is what high-energy astronomers study.

David Palmer
for Ask an Astrophysicist"

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971111e.html

The above refers to the temperature of the outside of a black hole. 
The information barrier stops us from knowing what is happening on the inside.

A black hole by definition is an area of space-time with a gravitational field so intense that its escape velocity is equal to or exceeds the speed of light.  A super-massive black hole can have a density less than the density of water.  http://en.wikipedia.org/wiki/Super-massive
The larger the radius of it's event horizon, the less dense it need be.  This does not imply that large black holes have to be hot.  The Universe fits the  definition of a black hole  as it is gravitationally bound.  It's temperature is only 2.75 degrees kelvin above absolute zero.  That's cold.
 

Offline @/antic

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Re: What is the temperature inside a Black Hole?
« Reply #20 on: 15/04/2012 19:35:34 »
Wow

Brilliant!

Thanks everyone
 

Offline Soul Surfer

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Re: What is the temperature inside a Black Hole?
« Reply #21 on: 16/04/2012 19:02:50 »
The original question was what is the temperature INSIDE a black hole.  Now we do not know this but assuming that the hole is quiet i.e. There isn't lots of stuff falling into it. It will also be very cold just inside the event horizon because as the stuff inside contracts towards, whatever it is (certainly NOT a mathematical singularity), the gravitational field will increase and photons from the centre of the contraction will not be able make it even to just inside the first event horizon. So there will in effect be whole series of event horizons inside each smaller and warmer than the last.

Taking this concept a little further.  As the succession of event horizons get smaller and the gravity gradient gets greater the Hawking radiation will get stronger until it is strong enough to soak up all the energy in the hole  that is the Hawking radiation from the horizon together with the time it takes to fall back into the hole represents all the energy in the hole.  This is a first bash at a serious proof of what is inside a simple scwartschild black hole.  It is not a "new theory" it is just based on what we currently agree upon and I challenge someone to prove it wrong!
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #22 on: 17/04/2012 08:48:52 »
clip
Taking this concept a little further.  As the succession of event horizons get smaller and the gravity gradient gets greater the Hawking radiation will get stronger until it is strong enough to soak up all the energy in the hole  that is the Hawking radiation from the horizon together with the time it takes to fall back into the hole represents all the energy in the hole.  This is a first bash at a serious proof of what is inside a simple scwartschild black hole.  It is not a "new theory" it is just based on what we currently agree upon and I challenge someone to prove it wrong!

I don't follow the logic of this.  Hawkin radiation only operates on the outside of the first (outermost) event horizon and is unaffected by anything inside the event horizon.  How can it 'soak up' what can't reach it?

On the other hand, if matter and antimatter should prove to be repulsive then a black hole could emit antimatter particles from inside the EH.
« Last Edit: 17/04/2012 09:15:26 by MikeS »
 

Offline imatfaal

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Re: What is the temperature inside a Black Hole?
« Reply #23 on: 17/04/2012 09:26:35 »
The original question was what is the temperature INSIDE a black hole.  Now we do not know this but assuming that the hole is quiet i.e. There isn't lots of stuff falling into it. It will also be very cold just inside the event horizon because as the stuff inside contracts towards, whatever it is (certainly NOT a mathematical singularity), the gravitational field will increase and photons from the centre of the contraction will not be able make it even to just inside the first event horizon. So there will in effect be whole series of event horizons inside each smaller and warmer than the last.
  Why is it quantised SSurfer?  Event horizons are cut-offs - I can see no reason for abrupt demarcations within the EH rather a gradual spectrum.  As this is GR based - to get a quantisation you need a form of quantum gravity, or do you intend that this would lead to QG? 

Quote
Taking this concept a little further.  As the succession of event horizons get smaller and the gravity gradient gets greater the Hawking radiation will get stronger until it is strong enough to soak up all the energy in the hole  that is the Hawking radiation from the horizon together with the time it takes to fall back into the hole represents all the energy in the hole.  This is a first bash at a serious proof of what is inside a simple scwartschild black hole.  It is not a "new theory" it is just based on what we currently agree upon and I challenge someone to prove it wrong!
  So you end up with a shell (or a sphere) of radiation at an interior EH corresponding with the total mass/energy of the BH?  The mass/energy of the BH is constantly and completely emitted via Hawking Radiation (the interior EHs acting as would a smaller BH - smaller=hotter) but this radiation would be entirely internal.

My problem is that I cannot see why you can postulate the interior EHs!  Once you have the interior EH then you can go onwards - but why are they there at all?
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #24 on: 17/04/2012 10:39:54 »
The original question was what is the temperature INSIDE a black hole.  Now we do not know this but assuming that the hole is quiet i.e. There isn't lots of stuff falling into it. It will also be very cold just inside the event horizon because as the stuff inside contracts towards, whatever it is (certainly NOT a mathematical singularity), the gravitational field will increase and photons from the centre of the contraction will not be able make it even to just inside the first event horizon. So there will in effect be whole series of event horizons inside each smaller and warmer than the last.
  Why is it quantised SSurfer?  Event horizons are cut-offs - I can see no reason for abrupt demarcations within the EH rather a gradual spectrum.  As this is GR based - to get a quantisation you need a form of quantum gravity, or do you intend that this would lead to QG? 

Quote
Taking this concept a little further.  As the succession of event horizons get smaller and the gravity gradient gets greater the Hawking radiation will get stronger until it is strong enough to soak up all the energy in the hole  that is the Hawking radiation from the horizon together with the time it takes to fall back into the hole represents all the energy in the hole.  This is a first bash at a serious proof of what is inside a simple scwartschild black hole.  It is not a "new theory" it is just based on what we currently agree upon and I challenge someone to prove it wrong!
  So you end up with a shell (or a sphere) of radiation at an interior EH corresponding with the total mass/energy of the BH?  The mass/energy of the BH is constantly and completely emitted via Hawking Radiation (the interior EHs acting as would a smaller BH - smaller=hotter) but this radiation would be entirely internal.

My problem is that I cannot see why you can postulate the interior EHs!  Once you have the interior EH then you can go onwards - but why are they there at all?

I can tell you why. The interior boundaries are created from space and time switching coordinates. I could show you math which explains how space and time switch roles... it doesn't really mean that space is really time and time is really space now, it's just a coordinate phenomena.

The gravitational effects of a black hole become so strong at the horizon, that space and time switch roles: space becomes timelike and time becomes spacelike. Then somewhere inside the black holes, these artefacts change back to normal and it will be here you find the inner boundary. With that said, Sean Carrol is dedicting a lot of his time to weild the idea that we are living inside a black hole, and I can only presume it would be inside the interior where space and time are acting normally again.
 

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Re: What is the temperature inside a Black Hole?
« Reply #24 on: 17/04/2012 10:39:54 »

 

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