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Author Topic: What is the temperature inside a Black Hole?  (Read 15939 times)

Offline yor_on

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Re: What is the temperature inside a Black Hole?
« Reply #25 on: 17/04/2012 12:53:48 »
Isn't that one only for one kind of solution Wulf?
For a Schwarzwild non rotating black hole if I remember right.

Or can you use it for rotating ones too?
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #26 on: 17/04/2012 14:01:20 »
Isn't that one only for one kind of solution Wulf?
For a Schwarzwild non rotating black hole if I remember right.

Or can you use it for rotating ones too?

Yes, you are right. The solutions which permit these conditions are calculated from the Schwarzchild metric.
 

Offline Soul Surfer

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Re: What is the temperature inside a Black Hole?
« Reply #27 on: 18/04/2012 00:04:41 »
mike and imfataal.  Maybe I am not expressing it well lets have another go. 

Consider the stuff at the instant the first event horizon forms.  THE EH is the point where the escape velocity becomes equal to the velocity of light and escape to "infinity" is not possible.  Now wait a bit and let the stuff collapse a little further. No more stuff is falling in so there is an empty space between the collapsing stuff and the EH.  Now this smaller blob has a higher gravitational field but escape for a short distance before falling back IS possible. Stuff then escape a bit but there will be a gap to the event horizon.  This is an inner collapsing "event horizon" of a type. Exactly the same quantum rules would apply it is possible for radiation to be emitted from that level but it would of course eventually fall back to the centre but it takes time doing this.  This inner horizon will shrink and become hotter as it gets smaller.  OK it will have to shrink to be pretty small before it gets hot enough.  The classic black hole anlaysis site   http://xaonon.dyndns.org/hawking/ says it will be  about 10^-9 the size of an atomic nucleus before it gets to radiate as much energy as the sun.  At the Planck length it is 10^21 times that of the sun.  (Mathematical singularities are still infinitely smaller than this and there is no limit to the energy in theory).  A quick estimate of the amount of energy in our universe is  around  10^10 galaxies with around 10^10 stars  plus about 10-100 times as much dark stuff  that makes around 10^21 give or take an order of magnitude or two.  So collapse to the Planck limit would produce an incredibly hot blob continually radiating and reabsorbing about as much energy as a whole universe.  Interesting!

Again I stress this is not a new theory and comes directly from applying the totally accepted rules.  the end result is not a mathematical singularity but a simple model that makes sense just by looking at what we know today.

Ęthelwulf  I agree and would go further to suggest that space and time actually DO change places and as the space contracts to a time line (Kerr black hole with ring singularity) that time expands to become multi dimensional space in a new universe seeded when the black hole collapsed (but that is a new theory and should not really be mentioned here.)  Penrose and his diagrams tends to assume that to get to a new universe via a black hole you have to do another reversal of space and time to restore the status quo but I do not think that this is really essential.
« Last Edit: 18/04/2012 08:49:55 by Soul Surfer »
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #28 on: 22/04/2012 08:36:22 »
Numerous event horizons at different gravitational potential? 

Differences in gravitational potential would normally imply different time dilation factors but at the event horizon time is already infinitely dilated (time stands still). 

Time can't go any slower inside the EH.  Maybe time reverses direction.  That would account for why something that is very hot from one reference point is actually very cold from another.  Maybe from a time reversed reference frame within the EH, black body radiation of the black hole is seen from the outside as black-body absorbtion. 

Obviously, this is pure speculation as we have little idea of the physics of black holes.

added
The above would seem to be in keeping with my reply #6 in this thread.
"So is absolute hot, the same as absolute cold?"
« Last Edit: 22/04/2012 08:44:06 by MikeS »
 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #29 on: 28/04/2012 08:35:14 »

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.

Is it possible that space and time switching coordinates is the same as the arrow of time reversing?

It would account for "space and time acting normally again".
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #30 on: 28/04/2012 09:24:53 »

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.

Is it possible that space and time switching coordinates is the same as the arrow of time reversing?

It would account for "space and time acting normally again".

You do realize that I don't believe an arrow of time exists? I won't go into the reasons why, but I should state that time is not linear - and for this reason, the whole idea of the coordinate change might be a load of rubbish.

In some loose way of speaking about this coordinate transformation, Space becomes Timelike, but what does that mean?

Well, in the view of mathematics, time goes one way: it looks like an arrow to us, because everything has a forward directionality, we never see things going back in time. Because of this, we humans often project this phenomenon subjectively and believe that time has some ''linearity'' about it. Well, when we say that space has become timelike, we mean that we are now [moving in space] as if we were linearly moving through time. This means we cannot move to the sides, we cannot move backwards.

We can however begin to move through time very freely. We may in fact, oscillate in time. This would mean there is no preferred directionality and this is what we mean when time becomes spacelike.

So as for time being viewed linear, that is dubious and the greater collection of physicists today don't believe that time flows linearly like a river. However, even with that said, even in the view of time being spacelike, linearity is not preserved, you may oscillate in the time dimenion.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #31 on: 28/04/2012 22:26:41 »
Numerous event horizons at different gravitational potential? 

Differences in gravitational potential would normally imply different time dilation factors but at the event horizon time is already infinitely dilated (time stands still). 

Time can't go any slower inside the EH.  Maybe time reverses direction.  That would account for why something that is very hot from one reference point is actually very cold from another.  Maybe from a time reversed reference frame within the EH, black body radiation of the black hole is seen from the outside as black-body absorbtion. 

Obviously, this is pure speculation as we have little idea of the physics of black holes.

added
The above would seem to be in keeping with my reply #6 in this thread.
"So is absolute hot, the same as absolute cold?"
Take what I said above as true... but there was something else I realized just there.

Time-reversed scenario's of black holes also go by another name, called white holes, but these objects spit out energy  instead of sucking it in. They may not exist however because it is generally believed they violate the second law of thermodynamics.
 

Offline Geezer

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Re: What is the temperature inside a Black Hole?
« Reply #32 on: 29/04/2012 01:41:43 »

Take what I said above as true...


Mr Scientist AW,

You do not hold a monopoly on science, so please do not tell other members to take anything as true without providing scientific proof.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #33 on: 29/04/2012 02:36:55 »

Take what I said above as true...


Mr Scientist AW,

You do not hold a monopoly on science, so please do not tell other members to take anything as true without providing scientific proof.

Fine I will provide proof. I thought my time since being here has shown I know what I am talking about. Fine, if you want to have proof, I will write up the math and link sources.
 

Offline Pmb

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Re: What is the temperature inside a Black Hole?
« Reply #34 on: 29/04/2012 02:45:02 »

Take what I said above as true...


Mr Scientist AW,

You do not hold a monopoly on science, so please do not tell other members to take anything as true without providing scientific proof.
A scientist who knows their stuff knows enough to never use the term "true" in a sentance.
 

Offline Pmb

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Re: What is the temperature inside a Black Hole?
« Reply #35 on: 29/04/2012 02:49:03 »
I've been a physicist for over 20 years now and one term I never use is "true" or something similar to it.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #36 on: 29/04/2012 02:55:12 »
I hope the equations come out right, the latex is overly sensative at this site. If they don't, go to reply to my response, and check the latex yourself and rewrite the equations.

We begin with the Schwartzschild metric, which is

8754278539e316a8359df20c241e1475.gif

The 136083e3f63740f1eba64ffff4583501.gif is really just 6ce08fe904251320ab42feaf004f3c4f.gif

This describes the metric of a two dimensional sphere... and yes, I do mean two dimensional, because we are dealing with the surface or what is called, ''the local neighbourhood of a black hole.''

The local neighbourhood is in fact just as good as a flat space approximation. b21cc641c1dfa8516916845e720d9821.gif is the Horizon, and any amount of ordinary time e358efa489f58062f10dd7316b65649e.gif actually amounts to no proper time a6f317b268ae825d94f832f970af607c.gif. Go back to the metric, when the coefficient of c0c09719ccc78915ee8c7fe511c56662.gif goes to zero a8b9496befe5fda9408c53e0acd40d6b.gif we imagine this has to do with clocks running slower. When 95a2e0d9651d40ae73cff3b209835ebc.gif, we have 6cd72a487fe35c2570f4c51877b20532.gif naturally then the coefficient of e317a271ae91ab09e9792bf050ae5220.gif on the 189512360cf6e57d7e07e5f93051c7c7.gif - term. When 2c3db681686c1b080e21688bf57b256a.gif for the 8c2d70f65b9efd0cc06b11d70d09447f.gif-term, then the 91bab4b8ff2f1410790a36f6fe04c2d5.gif. What is worse than this, is that it blows up to infinity with a negative sign, and thus 623c00a0d45d443875ef6b2ddb74f292.gif and 75378ea934d3857175c247f09f73704a.gif interchange signs, they effectively switch roles. This means you will begin to move through space linearly and without recourse.

Now, saying space has become timelike maybe slightly faulty, because it preassumes that time is linear. Time is not linear, in that it flows like a river from the past to the future. Next I will find references to show you this statement is what current science tells us.

« Last Edit: 29/04/2012 03:33:43 by Ęthelwulf »
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #37 on: 29/04/2012 02:57:53 »
http://arxiv.org/abs/0812.0240

I feel that confident with the famous George Ellis, this is all the references I need. Now, if time is not a river which extends from our past to future, then time cannot be linear. Besides, time is far from linear when you think about geometrical consequences of GR.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #38 on: 29/04/2012 02:58:36 »
I've been a physicist for over 20 years now and one term I never use is "true" or something similar to it.

It's as true as we know it today. Do we think the curvature of spacetime is true?

If you are scared to use the word, you are not really agreeing with science.
 

Offline Geezer

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Re: What is the temperature inside a Black Hole?
« Reply #39 on: 29/04/2012 05:30:03 »
AW,

You have been warned repeatedly that you may not patronize other members.

Please do not do that again. I think you are very familiar with what will happen if you do.

 

Offline MikeS

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Re: What is the temperature inside a Black Hole?
« Reply #40 on: 29/04/2012 05:50:26 »
http://arxiv.org/abs/0812.0240

I feel that confident with the famous George Ellis, this is all the references I need. Now, if time is not a river which extends from our past to future, then time cannot be linear. Besides, time is far from linear when you think about geometrical consequences of GR.

A river always flows downhill but not always at the same rate.
If by linear you mean as in a straight line with equal divisions then from a local time frame, time is always linear.  Observed from any other non-local frame then time is seldom linear unless that frame is co moving.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #41 on: 29/04/2012 05:56:03 »
AW,

You have been warned repeatedly that you may not patronize other members.

Please do not do that again. I think you are very familiar with what will happen if you do.

Where have I patronized anyone?

Sorry Mike, I will answer you soon. I would like to be shown how I have been patronizing.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #42 on: 29/04/2012 05:56:53 »
AW,

You have been warned repeatedly that you may not patronize other members.

Please do not do that again. I think you are very familiar with what will happen if you do.

Where have I patronized anyone?

Sorry Mike, I will answer you soon. I would like to be shown how I have been patronizing.

If you have picked me up wrong, I'd like an apology. Just like you read my last thread as a new theory here but was a question. mistakes have happened I guess.
 

Offline Pmb

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Re: What is the temperature inside a Black Hole?
« Reply #43 on: 29/04/2012 06:16:23 »
Do we think the curvature of spacetime is true?
As I said above, "true" is a word I never use. In this case it is not okay to think of curvature of spacetime is true. To be precise, this is not even a poorly phrased question. In the absense of matter the spacetime will expected not to be curved. If Einstein's equations are valid and region S of spacetime is calculated to have spacetime curvature then the value of spacetime is calculated to be non-zero then the appropriate to say that the spacetime region is curved.

Now it's my turn to ask you a question. When I go out of the way to say that never is a word I use then why do you go out of your way to ask me the same question again?
If you are scared to use the word, you are not really agreeing with science.
Please show me in this thread or any other thread where I said that I was scared to use? Also, please post a proof whose conclusion is that I'm not really agreeing with science.

There are only a few instances wherein it is okay to say that it is okay to conclude that something is true/false.

Correction: There actually are instances where it is okay to say something is true or false, or right or wrong. I made a mistake in saying otherwise. I've been off my game lately. This is not a result of being right or wrong. It is a result of having SSRI disorder syndrom. It's one of the reasons I haven't been posting as much as I used to.

Let me give you an example:

Correct example of when it's okay to say that something is true; Saying that the invariance of the speed of light is true is an example of when it is not okay to say that the speed of light is being invariance is true. We cannot say this as true because it is concievable that the speed of light might one day be measured to be different that c.

There are, of course, othertimes where I use the term "true" in error which I say when I simply make a mistake in saying so (being human I will of course, make an error at times).

It is also "true" to say that the number of golf balls in a bucket is three when the sum is two and I add one. It is true that the sum after adding one to make it three.

I might have made an error above because it can be quite easy to make a mistake in terminology. Be careful in making assertions like the one you ended your post with, i.e. be cautious when you claim that I am not really agreeing with science.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #44 on: 29/04/2012 06:22:02 »
Do we think the curvature of spacetime is true?
As I said above, "true" is a word I never use. In this case it is not okay to think of curvature of spacetime is true. To be precise, this is not even a poorly phrased question. In the absense of matter the spacetime will expected not to be curved. If Einstein's equations are valid and region S of spacetime is calculated to have spacetime curvature then the value of spacetime is calculated to be non-zero then the appropriate to say that the spacetime region is curved.

Now it's my turn to ask you a question. When I go out of the way to say that never is a word I use then why do you go out of your way to ask me the same question again?
If you are scared to use the word, you are not really agreeing with science.
Please show me in this thread or any other thread where I said that I was scared to use? Also, please post a proof whose conclusion is that I'm not really agreeing with science.

There are only a few instances wherein it is okay to say that it is okay to conclude that something is true/false.

Correction: There actually are instances where it is okay to say something is true or false, or right or wrong. I made a mistake in saying otherwise. I've been off my game lately. This is not a result of being right or wrong. It is a result of having SSRI disorder syndrom. It's one of the reasons I haven't been posting as much as I used to.

Let me give you an example:

Correct example of when it's okay to say that something is true; Saying that the invariance of the speed of light is true is an example of when it is not okay to say that the speed of light is being invariance is true. We cannot say this as true because it is concievable that the speed of light might one day be measured to be different that c.

There are, of course, othertimes where I use the term "true" in error which I say when I simply make a mistake in saying so (being human I will of course, make an error at times).

It is also "true" to say that the number of golf balls in a bucket is three when the sum is two and I add one. It is true that the sum after adding one to make it three.

I might have made an error above because it can be quite easy to make a mistake in terminology. Be careful in making assertions like the one you ended your post with, i.e. be cautious when you claim that I am not really agreeing with science.

Actually it was a poor question, because even in the absence of matter spacetime can be curved due to Einsteins equations, such as gravitational waves. They are not trivial...

I can't post a proof. I am generalizing here. Sure there are things in science we can be sure about and say is true. An apple falls because of gravity is true to current belief. What is also true is that electrons are spin 1/2 particles and that photons travel at the speed of light.

What you implied to me, was that you never use the word ''true'' in physics. What word do you use then with subjects which are well-written and experimentally-varified upon?

I don't, for instance, go around saying ''yes, possibly'' to anything which is at the core of physical understanding. If someone asked me, ''is an electron a Fermion?'' I wouldn't reply to this, ''yes maybe''. I'd say, ''yes, that is true.''

Why is that wrong?
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #45 on: 29/04/2012 06:22:54 »
In this case, I said according to the mathematics, coordinate changes will occur. I said, take what I said it true.

Nothing is wrong with this statement.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #46 on: 29/04/2012 06:41:13 »
AW,

You have been warned repeatedly that you may not patronize other members.

Please do not do that again. I think you are very familiar with what will happen if you do.

Can I just say for the record in case Geezer does find a reason to banish me, is that the the partonization was supposed to be in this line:

''If you are scared to use the word, you are not really agreeing with science.''

I did not however imply he was. I said ''if''. I know plenty of people in science who would say the same thing about anyone. I wouldn't dodge a question by saying ''maybe'' to a simple question like what is the spin of a fermion, is it a 1/2 spin? I wouldn't go, ''maybe''... I would say ''true''. If I said ''maybe'' it would mean to be taken that I have reservations on my answer, that I perhaps don't entirely agree with what science has to say.
 

Offline Ęthelwulf

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Re: What is the temperature inside a Black Hole?
« Reply #47 on: 29/04/2012 06:48:35 »
http://arxiv.org/abs/0812.0240

I feel that confident with the famous George Ellis, this is all the references I need. Now, if time is not a river which extends from our past to future, then time cannot be linear. Besides, time is far from linear when you think about geometrical consequences of GR.

A river always flows downhill but not always at the same rate.
If by linear you mean as in a straight line with equal divisions then from a local time frame, time is always linear.  Observed from any other non-local frame then time is seldom linear unless that frame is co moving.

A river is just an example... the old saying ''the river of time'' .... means it flows linearly from point to another, which as George Ellis clearly points out, it doesn't.

For locality we surely mean observer. And I'd agree, take the human observer who is aware of their surroundings. Their perception is strictly local with time and their experience of it --- but our experience of time arises because of a gene regulation inside our heads, the so-called, suprachiasmatic nucleus.

Beleiving for a moment that time exists objectively (outside the human perception) time is then part of the understanding of the manifold which requires a non-linear geometry. That would be most important, not the perception of it.
 

Offline Geezer

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Re: What is the temperature inside a Black Hole?
« Reply #48 on: 29/04/2012 06:52:52 »
AW,

You have been warned repeatedly that you may not patronize other members.

Please do not do that again. I think you are very familiar with what will happen if you do.

Can I just say for the record in case Geezer does find a reason to banish me, is that the the partonization was supposed to be in this line:

''If you are scared to use the word, you are not really agreeing with science.''

I did not however imply he was. I said ''if''. I know plenty of people in science who would say the same thing about anyone. I wouldn't dodge a question by saying ''maybe'' to a simple question like what is the spin of a fermion, is it a 1/2 spin? I wouldn't go, ''maybe''... I would say ''true''. If I said ''maybe'' it would mean to be taken that I have reservations on my answer, that I perhaps don't entirely agree with what science has to say.

Nice try, but if you had said you were sorry to the other members, you might have been saved. Instead you have earned a one week vacation to think about it.
 

Offline Pmb

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Re: What is the temperature inside a Black Hole?
« Reply #49 on: 29/04/2012 07:40:09 »
Ęthelwulf - Above I asked you several questions which you have not yet answered. When you answer those I will respond to the rest of your comments. And I'm referring to all my questions, not just one of them.

Also the question you referred to above is not a poor question. So if you answer the question already posed and if you can figure out why the question I just referred to was not a poor one then I'll finish responding to your comments.
 

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Re: What is the temperature inside a Black Hole?
« Reply #49 on: 29/04/2012 07:40:09 »

 

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