Hawking radiation

[brucep]

Bruce, was the use of the word fact an error above? If not could you provide a reference for the observation....

What constitutes a fact for you? It's a theoretical fact even though it's been detected in an analog experiment. I suspect that will be the only way we can actually detect Hawking radiation. William Unruh is the author of the paper revealing the success of an analog experiment. At least one of the authors. The summary gives a more realistic picture than me. Pretty cool esperiment.
http://arxiv.org/abs/1008.1911
Actually that is only one of several claims to have detected Hawking radiation in analog experiments. Always be lots of skepticism by those who think analog experiments are somehow fake.

 

[Q-reeus]

While as an amateur at this game there is much I don't understand, what I do understand is that talk and claims against what is generally accepted as mainstream is cheap, and even cheaper on forums such as this that open to any and every Tom , Dick, and Harry.

Which logically implies you must have an extremely low self-esteem. Obviously logic has nothing to do with your actual attitude which is unabashedly vain. And yes - YOUR talk is certainly cheap. Not an ounce of humility or honesty - for instance refusing to acknowledge basic errors pointed out in first part of #34.

My other good friend "the god" will probably give you a confidence boost later on today, as he is pretty apt at clinging to someone's apron strings, as he obviously is clinging to yours.

Such often repeated outrageous tactics, likely intended as some kind of 'divide and conquer' strategy, ought imo to have been grounds for a life ban. Just why that has not been enacted after so much underhanded false insinuations and other forms of baseless character assassination, is beyond me.

I reiterate my thoughts on Hawking Radiation and the reputable links and articles supporting it,
It is generally accepted as a viable quantum effect and remains so until evidence shows otherwise.
http://link.springer.com/article/10.1007/BF01219075#page-1

Particle Creation by a Black Hole as a Consequence of the Casimir Effect.
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http://arxiv.org/pdf/hep-th/0011198v2.pdf

Conclusion:
We have found the renormalized energy-momentum tensor for massless scalar field on background of 1+1 dimensional Schwarzschild black hole for two parallel plates with Dirichlet boundary conditions, by making use of general properties of stress tensor only. We propose that if we know the stress tensor for a given boundary in Minkowski space-time, the Casimir effect in gravitational background can be calculated. We have found direct relation between trace anomaly and total Casimir energy. In addition, by considering the Hawking radiation for observer far from black hole, who is the same as Minkowski observer, this radiation contributes to the Casimir effect. In this paper we have derived three renormalized energy-momentum tensors for our case of study. This is due to selecting three vacuum states for calculation. If we consider Boulware vacuum, stress tensor will have two parts: boundary part and gravitational part. But using Hartle-Hawking and Unruh vacuums will result in another term added to stress tensor, which respectively corresponds to a bath of thermal radiation and Hawking radiation. It seems that similar results can be obtain for four-dimensional Schwarzschild black hole

As is overwhelmingly the case, you quote that which you do not understand - being completely mathematically illiterate. Likely incapable of solving even a simple quadratic equation. Such purely theoretical articles are churned out regularly in accordance with 'publish or perish' needs. Zero observational support. You did notice for instance that this article is not even dealing with a supposed 'real' BH - just a higly idealized and simplified 1+1 D theoretical construct? But to call you out - having cut/pasted that piece - point to where it so much as acknowledges let alone answers the issues I have raised - particularly in #34.

 

[Q-reeus]

https://en.wikipedia.org/wiki/Black-body_radiation

4th paragraph down.

You actually believe that 'black body' = 'black hole'?!

 

[paddoboy]

Which logically implies you must have an extremely low self-esteem.

Not at all, I'm just man enough to face facts, and realise what ever you claim as logic or illogical is tainted somewhat with an agenda.

Such often repeated outrageous tactics, likely intended as some kind of 'divide and conquer' strategy, ought imo to have been grounds for a life ban. Just why that has not been enacted after so much underhanded false insinuations and other forms of baseless character assassination, is beyond me.

Such comical false indignation does nothing for your character...You are a real card...the joker!
The other joke of course is your divide and conquer nonsense, I mean just over the last week, the three or four alternative opinions we have had all greatly disagree...divide and conquer you say yeah sure!
But you go ahead and align yourself with the god......should be interesting to say the least

As is overwhelmingly the case, you quote that which you do not understand - being completely mathematically illiterate. Likely incapable of solving even a simple quadratic equation. Such purely theoretical articles are churned out regularly in accordance with 'publish or perish' needs. Zero observational support. You did notice for instance that this article is not even dealing with a supposed 'real' BH - just a higly idealized and simplified 1+1 D theoretical construct? But to call you out - having cut/pasted that piece - point to where it so much as acknowledges let alone answers the issues I have raised - particularly in #34.

Again, your opinion is worth jack...and Hawking Radiation stands as reasonably applicable, despite your objections.
But again, if those objections have any substance, then you know what to do, hey?

 

[The God]

The fact that black holes radiate a thermal spectrum became an important part of the path to quantum gravity.

But Unruh in the linked paper feels otherwise.

When the thermal emission was originally discovered by Hawking, it was believed to be a feature peculiar to black holes. Our experiments, and prior numerical work [6,12], demonstrate that this phenomenon seems to be ubiquitous, and not something that relies on quantum gravity or Planck-scale physics.

;

Actually that is only one of several claims to have detected Hawking radiation in analog experiments. Always be lots of skepticism by those who think analog experiments are somehow fake

Wrong again. No one says that analogue experiments are fake, what is raised is the the analogy type extension of results to unobeservable aspects in different domain. For example results of an experiment conducted on a dumb hole (sound equivalent of Black Hole) are analogically extended to Black Hole, this aspect is open to question, not the experiment.

 

[Q-reeus]

Again, your opinion is worth jack...and Hawking Radiation stands as reasonably applicable, despite your objects.
But again, if those objects have any substance, then you know what to do, hey?

When someone is genuinely rattled, it often shows up as, say, repeated spelling errors. Or did you really mean 'objects' rather than 'objections'?! Anyway, decoded bottom line there is paddoboy 'the great' was incapable of answering my challenge in last sentence of #42. And of course psychologically incapable of admitting that. Not a good score sheet - paddoboy.

 

[The God]

and as long as you keep ignoring requests for reputable links

You are a repeat-liar, you lied again.

I gave you that reputed link which would have taught you "How to find out th surface area and volume of a sphere when radius value is given".

If you have learnt that then please calculate the value of volume of a sphere with radius = 2.95 kms, and prove to yourself that a star core of solar mass shall have a volume of 107 cubic Kms when its core is just at its Schwarzschild radius; it will not have a volume of 5 Kms as claimed by you.

The type of links and references which you are requesting are supplied with comments to those, who have the ability to decipher and understand. You have yet to convince me that you have that ability. Popscience, yes, you are a maestro, you can teach the world a lot there.

 

[The God]

The below paper is a good read and has touched upon HR issue as well, the below extract is taken fom the paper which highlights.......

arXiv:gr-qc/9803049v2

How can one interpret Hawking radiation? The central point is that the notion of vacuum (and therefore also the notion of particles) loses its invariant meaning in the presence of a dynamical background. Incoming modes of the quantum field are redshifted while propagating through the collapsing geometry, which is why the quantum state of the outgoing modes is different. If the initial Towards a Full Quantum Theory of Black Holes 5 state is a vacuum state, the outgoing state contains “particles”. The redshift is especially high near the horizon, where the modes spend a long time before escaping to infinity. This is the reason why Hawking radiation is present very long after the collapse is finished for a comoving observer, contrary to what one would naively expect. The presence of the horizon is also responsible for the thermal nature of the radiation, since no particular information about the details of the collapse can enter. It turns out that the vacuum expectation value of the energy-momentum tensor of the quantum field is negative near the horizon, corresponding to a flux of negative energy into the hole (this is the basis for the pictorial interpretation of the Hawking effect, where one partner of a pair of virtual particles can fall into the hole, thus enabling the other partner to become real and escape to infinity, where it can be observed as Hawking radiation). For details of this scenario, I refer to e.g. Wipf (this volume), ’t Hooft (1996, and this volume), Birrell and Davies (1982), Wald (1994), and the references therein. The negativity of this expectation value is, like the Casimir effect, a genuine quantum feature. This negative energy flux leads to a decrease of the black hole mass and is equal to the positive flux of the Hawking radiation at infinity. From a simple application of Stefan-Boltzmann’s law

 

[Q-reeus]

If you have learnt that then please calculate the value of volume of a sphere with radius = 2.95 kms, and prove to yourself that a star core of solar mass shall have a volume of 107 cubic Kms when its core is just at its Schwarzschild radius; it will not have a volume of 5 Kms as claimed by you.

The God - I concur with you that paddoboy made a very basic blunder elsewhere in conflating a linear dimension quantity with volume. However it's also true that interior volume for an assumed stellar core on the verge of being a 'BH' is very 'Tardis like'. Meaning in highly curved non-Euclidean spacetime, the simple formula applicable in Euclidean flat spacetime breaks down badly. In fact, afaik no-one even attempts to specify 'interior volume' for a supposed BH.

 

[The God]

But you go ahead and align yourself with the god......should be interesting to say the least

I am not here for people like him, he is an independent man, with sound ability to think, analyse and question. He has demonstrated that here. I am here for people like you, who have the brain, the same tissues, but absolutely rendered it useless by not at all thinking creatively.

People like you can acquire knowldege in due course, but they cannot contribute to the enhancement of knowledge. In early life the knowledge acquiring aspect is predominant but after certain age for interested human beings both these aspects (acquiring and enhancing) can go parallel. In your case it seems you have not even come to that stage. I will leave this forum the day, I see that you have rationally with sound argument, have questioned a prevalent hypothesis or theory. The day you start asking questions with authority...that why not -ve energy particle this side?...that day my job is done.

As of now, your stand is pathetically slavish...those guys have said it and it is peer reviewed...so it must be true.

See how Daecon, rushed to offer an explanation for Brucep....and got hurt.

 

[paddoboy]

The God - I concur with you that paddoboy made a very basic blunder elsewhere in conflating a linear dimension quantity with volume. .

No paddoboy did not make any basic error....Most realise to squeeze any volume to within 5km would relate to a diameter....But you please yourslef what you believe.
To the great annoyance of the god, the tutorial stands as correct and unchanged, because sensible people saw it that way...The only exception so far being three anti science trolls.

 

[The God]

The God - I concur with you that paddoboy made a very basic blunder elsewhere in conflating a linear dimension quantity with volume. However it's also true that interior volume for an assumed stellar core on the verge of being a 'BH' is very 'Tardis like'. Meaning in highly curved non-Euclidean spacetime, the simple formula applicable in Euclidean flat spacetime breaks down badly. In fact, afaik no-one even attempts to specify 'interior volume' for a supposed BH.

Agreed to the extent of vulgur nature of spacetime around BH of smaller masses.......The dispute was in bad taste and continued with his insistence of writing volume with kms and vacillating every now and then about what is 5 Kms.

 

[paddoboy]

I am not here for people like him, he is an independent man, with sound ability to think, analyse and question. He has demonstrated that here. I am here for people like you, who have the brain, the same tissues, but absolutely rendered it useless by not at all thinking creatively.

Grab hold of them apron strings my boy!
You are here for one reason....To preach your general non standard accepted view on cosmology which in most part has been proven to be pseudoscience.
Oh, and question whatever pedant nonsense you can find to try and show me in gross error...Keep trying, and while your at it, you still have many facts I have listed about BH's in the BH tutorial to correct...
You wont do that though because it will reveal who you are.

People like you can acquire knowldege in due course, but they cannot contribute to the enhancement of knowledge. In early life the knowledge acquiring aspect is predominant but after certain age for interested human beings both these aspects (acquiring and enhancing) can go parallel. In your case it seems you have not even come to that stage. I will leave this forum the day, I see that you have rationally with sound argument, have questioned a prevalent hypothesis or theory. The day you start asking questions with authority...that why not -ve energy particle this side?...that day my job is done.

As of now, your stand is pathetically slavish...those guys have said it and it is peer reviewed...so it must be true.

See how Daecon, rushed to offer an explanation for Brucep....and got hurt.

As of now you are a big sook. Go cry on someone else's shoulder about the demolishment that big bad paddoboy has given you...
I stand by everything I have said, despite your childish vindictive crap.
You have failed...big time.

 

[The God]

....Most realise to squeeze any volume to within 5km would relate to a diameter....

Two points: I never spoke of any Schwarzchild diameter and I don't believe the phrase is used in professional circles very much, still that is being pedantic

Both are self explanatory..errrrr.... Contradictory.

 

[paddoboy]

You are a repeat-liar, you lied again.

Am I? Says who? You?
Well my friend one of us certainly is a liar and a fraud to boot and it ain't me, despite your Bollywood style acting ability.
And as I said earlier, I'm comfortable with letting your's and mine peers decide that...
So there we have it....The ball's in your court.

 

[paddoboy]

Both are self explanatory..errrrr.... Contradictory.

No, as I said, most see it as I meant it, a diameter. I never said "schwarzchild diameter", a phrase very rarely used in physics. We always refer to the Schwarzchild radius not a Schwarzchild diameter....
And my dear friend, that's why the tutorial still stands correct and unchanged.

 

[paddoboy]

When someone is genuinely rattled, it often shows up as, say, repeated spelling errors. Or did you really mean 'objects' rather than 'objections'?! Anyway, decoded bottom line there is paddoboy 'the great' was incapable of answering my challenge in last sentence of #42. And of course psychologically incapable of admitting that. Not a good score sheet - paddoboy.

More psychoanalysis on your part...is that the best you can do?
Oh and thanks for pointing out that error to me, my mistake, as I'm watching the RU football World Cup and not giving my full attention to the trolls.
Your challenge? I'm not interested in your challenge. As I have said, if you had anything of concrete nature to re-enforce whatever your views on HR and GR are, you would not be here.
That's my challenge to you.
Oh, and the god probably needs some support. He appears to be floundering as he was in the Black Neutron Star thread and the others under rajesh's name.

 

[paddoboy]

I will leave this forum the day, I see that you have rationally with sound argument, have questioned a prevalent hypothesis or theory. The day you start asking questions with authority...that why not -ve energy particle this side?...that day my job is done.

I find most prevalent accepted theories as reasonably on solid ground...afterall that's why they are the mainstream accepted theories isn't it?
But rest assured my dear fellow, I will certainly keep questioning the many anti science nuts, the would be's if they could be's with their over inflated egos and conspiracy theories, for as long as is necessary. And when needed I will supply reputable links to refute their rubbish and required references which I have always done.
That will continue.

See how Daecon, rushed to offer an explanation for Brucep....and got hurt.

Obviously you are unaware how childishly stupid saying something like that is. rajesh acted the same childish way with regards to myself...
Got hurt??? Are you for real?
Gee my friend, you may be obviously an anti science crank, but saying something like that is really just kindergarten talk and not worthy of someone like yourself.... an electrician, was it not?

 

[Q-reeus]

More psychoanalysis on your part...is that the best you can do?
Oh and thanks for pointing out that error to me, my mistake, as I'm watching the RU football World Cup and not giving my full attention to the trolls.

Huh? Seeing double while looking in a mirror? You were rattled! Honestly, why not just follow RU and quit pretending to be capable of evaluating non-trivial concepts in physics.

Your challenge? I'm not interested in your challenge.

You can't meet it. Be honest for a change.

As I have said, if you had anything of concrete nature to re-enforce whatever your views on HR and GR are, you would not be here.
That's my challenge to you.

Forgotten already? To repeat - this is a bloody FORUM - nitwit! Go check the dictionary definition.

Oh, and the god probably needs some support. He appears to be floundering as he was in the Black Neutron Star thread and the others under rajesh's name.

If I were The God, that piece would be the last straw. There are I assume still in place strict forum rules regarding making repeated false accusations. This may have an interesting finale.

 

[OnlyMe]

So, a mistaken use of the word?

My initial question was only because I thought you had worded that sentence badly. Not because I disagreed with what I thought you meant! That said...

What constitutes a fact for you?

It is important to use clear language in discussions like this. Words like fact, theory and even speculation, have very different implications on whatever subject they are associated with.., and none of them mean exactly the same thing.

Hawking radiation does not even rise to the level of a theory, since it does not describe anything that is or can be observed. At best it is speculation, about a possible solution to one of the problems that emerges from what is believed may happen at the event horizon of a black hole.

It's a theoretical fact ..,

theoretical fact....?

• Theories attempt to describe things we can observe.
• Facts are things we can observe, or direct conclusions based on observation.
• Speculation is even step further from what we do know to be, than a theory. It's more like exploring the implications of how we imagine, what we know as a fact or theory, may apply to conditions we are unable to observe or test.

What is a theoretical fact?

Hawking radiation is speculation about something that is imagined or believed to occur. Even the concept, of virtual particles (which are inherently untestable), is speculative.., emerging initially from within an unrelated theory.

... even though it's been detected in an analog experiment. I suspect that will be the only way we can actually detect Hawking radiation.

No one has detected Hawking radiation. An analogue is something that is similar to or comparable to something else. In this case a situation or system that is similar to what is speculated to occur in the case of Hawking radiation. But the conditions in any classical system that we can observe and test, are so far from what we believe the conditions existing at an event horizon would be, that the analogue system at best demonstrates a similarity, it can not prove anything about black holes or the factual existence of Hawking radiation.

William Unruh is the author of the paper revealing the success of an analog experiment. At least one of the authors. The summary gives a more realistic picture than me. Pretty cool esperiment.
http://arxiv.org/abs/1008.1911
Actually that is only one of several claims to have detected Hawking radiation in analog experiments. Always be lots of skepticism by those who think analog experiments are somehow fake.

Where in the paper you referenced is there a claim to have detected Hawking radiation? Again, no one has detected Hawking radiation, even where in an analogue system there are similarities. No one has even detected virtual particles, even while they remain a significant prediction of an otherwise successful quantum theory (that does describe things we can observe and test).