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anonymous: on 2/9/10 at 17:14pm UTC, wrote Infinite curvature? how so, yet only a straight line has no end or...

Eckard Blumschein: on 11/4/09 at 23:07pm UTC, wrote Dear Thomas Sotiriou, Because I agree with Terry Padden, I am looking in...

NN: on 10/31/09 at 15:17pm UTC, wrote All the talk of quantum gravity explaining away the behavior of black holes...

B N Sreenath: on 10/26/09 at 17:31pm UTC, wrote Dear Ted & Thomas, You people seem to think that Black-Hole is a region of...

amrit: on 10/15/09 at 17:06pm UTC, wrote Dear Thomas I would say: In centre of black hole curvature of timeless...

Terry Padden: on 10/14/09 at 6:18am UTC, wrote NN Someone should tell you that Uncle Al is Alan Schwartz; and he has...

Anonymous: on 10/12/09 at 2:35am UTC, wrote ‘… It would actually be much more exciting if there were no...

NN: on 10/11/09 at 7:25am UTC, wrote i tend to agree with the initial comment of Uncle Al. He is a personality...


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Joe Fisher: "Dear Gary D. Simpson and John R. Cox, Please stop trivializing this site..." in Sounding the Drums to...

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Sounding the Drums to Listen for Gravity’s Effect on Quantum Phenomena
A bench-top experiment could test the notion that gravity breaks delicate quantum superpositions.

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Accounting for quantum fuzziness could help us measure space and time—and the cosmos—more accurately.

Bohemian Reality: Searching for a Quantum Connection to Consciousness
Is there are sweet spot where artificial intelligence systems could have the maximum amount of consciousness while retaining powerful quantum properties?

Quantum Replicants: Should future androids dream of quantum sheep?
To build the ultimate artificial mimics of real life systems, we may need to use quantum memory.

Painting a QBist Picture of Reality
A radical interpretation of physics makes quantum theory more personal.

September 19, 2017

CATEGORY: What's Ultimately Possible in Physics? Essay Contest (2009) [back]
TOPIC: Might black holes reveal their inner secrets? by Ted Jacobson and Thomas Sotiriou [refresh]
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Author Thomas Sotiriou wrote on Oct. 5, 2009 @ 16:22 GMT
Essay Abstract

Black holes harbor a spacetime singularity of infinite curvature, where classical spacetime physics breaks down, and current theory cannot predict what wil l happen. However, the singularity is invisible from the outside because strong gravity traps al l signals, even light, behind an event horizon. In this essay we discuss whether it might be possible to destroy the horizon, if a body is tossed into the black hole so as to make it spin faster and/or have more charge than a certain limit. It turns out that one could expose a “naked” singularity if effects of the body’s own gravity can be neglected. We suspect however that such neglect is unjustified.

Author Bio

Ted Jacobson earned his Ph.D. at the University of Texas at Austin in 1983. After post-doctoral positions at the Poincar{\'}e Institute, UC Santa Barbara, and Brandeis, he joined the faculty at the University of Maryland in 1988. He is a Fellow of the American Physical Society. Thomas Sotiriou did his graduate work at SISSA, Trieste and earned his PhD in 2007. He spent time as a research associate at the University of Maryland, College Park and he is currently a research associate at the University of Cambridge.

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Uncle Al wrote on Oct. 6, 2009 @ 01:15 GMT
Unbinding a body by spin is straighforeward. Calculating the trajectory of your spinup mass through severely distorted spacetime proximate to the event horizon is not a trivial task. Roche limit on approach! **Black holes are strongly bound** (millisecond pulsars with 11% lightspeed equtorial spin speed are unremarkable). I am not optimistic about your approach, even in principle.


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Robert L. Oldershaw wrote on Oct. 6, 2009 @ 02:24 GMT
I have often wondered whether the free electron might be a naked singularity, or more likely a thinly veiled [by a fairly compact envelope of lower scale particles] singularity.

Are there properties of the UNBOUND electron that conflict with this idea?


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Lawrence B Crowell wrote on Oct. 6, 2009 @ 19:30 GMT
I thought your paper was interesting. It appears that attempting to spin up a black hole by shooting spinning particles into it reduces the avenue of approach to zero as the black hole approaches extremal condition.

A number of years ago I did a calculation with this in mind. I considered a black hole with a small angular momentum and assumed that J - -> J + δJ. In working this out I found that a part of the solution appeared to be a gravity wave. I figured that the gravity wave would remove some of the angular momentum imparted to the BH. I unfortunately did not pursue this, but I figured there is some sort of black hole thermodynamic result, similar to the third law. If you impart some angular momentum to a BH a portion of that is radiated away in gravity waves. I conjecture then that as you impart spinning particles into a BH and approach the extremal condition that a greater percentage of that angular momentum is removed by gravity waves. In the limit you approach the extremal condition that should approach unity --- all the angular momentum is radiated away so as to prevent the extremal condition.

Cheers LC

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Terry Padden wrote on Oct. 9, 2009 @ 06:25 GMT
Ted & Thomas

In the first sentence of your abstract you write "where classical spacetime physics breaks down, and current theory cannot predict what will happen". The first part of this is literally meaningless. There is not and cannot be, ever, a breakdown in physical spacetime. It would be, in the language of my essay, "Unreasonable". Where is the empirical measured evidence for such a breakdown ? The clause can only have meaning as a tautology for the second part - which is 100% true. High energy density (and other) Singularities are unavoidable (an example of my ultimate impossibility) with current formalisms - Rationally. SIngularities are Unreasonable but Rational. I did not have space to include this one and many others among my 10 points.

Quantum physicists often boast their theories are the most accurate predictive science ever developed. Penrose (in 2nd Para, page 61 "The Nature of Space and Time" co-author S Hawking) makes the same boast for GR. Both are right. QM applies in HEP (High Energy density physics) - hence all that expenditure in Geneva. GR applies in LEP (Low energy density physics). Somewhere (Buckyballs ?) there is a transition.

Abhay Ashtekar writes (in "Loop Quantum Gravity: an Overview" arXiv 0812.0177) " This is the regime where we can no longer trust general relativity. Thus, the big bang is a prediction of general relativity precisely in a domain WHERE IT IS INAPPLICABLE. Although in the framework of general relativity the universe did begin with a big-bang, there is NO REASON TO BELIEVE that the real, physical universe did. To know what really happened, one needs a quantum theory of gravity."

I understand why physicists are reluctant to promote Ashtekar's conclusion since they are the ones who foisted the reality of the Big-Bang on the public. Although it does seem to undermine all forms of creationism.

However in relation to your essay I think Ashtekar's conclusion about inapplicable formalism applies as a Limiting Principle in accordance with the instructions for the essays. The cosmic censorship hypothesis is unnecessary. It is redundant because of a NBH (No Black Holes) principle. Increasing energy density eventually produces quantum radiation (Hawking Radiation is an approximate version of the - theoretical only - limiting case). So a BH can never form - and the effective formalism must transform from GR to QM; or some as yet unknown combination.

For some reason you seem to think that the mathematical / logical problems of the rational formalism of GR can be fixed by physical means - spinning masses. It can't be done. Only a change of formalism can fix singularities, as Ashtekar has shown. I think you are being unreasonable and irrational to hypothesise such a physical solution to a mathematical problem.

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Steve Dufourny wrote on Oct. 9, 2009 @ 13:52 GMT
Hi all ,

It's interesting all your extrapolations .Always likeable to see the ideas of all .

Personally ,I have my opinion .All is complementary and has a rule ....

Without any doubt ,all is linked with these rotating spheres ,quantum and cosmological physical spheres .Without any doubt .The BH IS A SPHERE TOO ,and this system is coded since the beginning and has a rule of complemenatrity like all .

The BH is a equilibrium of evolution ,this system ,super attractif is balanced in an evolution point of vue .What I find relevant is the diameter and the volmume of this sphere and its properties .

The rotations there too explain all about the system ,thus the mass explains all ,the gravity thus explains all ,the rotating spheres thus explain all .

To encircle the rule of these BH ,centers ,a whole point of vue is essential .

The conscious too with the evolution of harmonisation .A BH isn't a door towards time or multiverses ,BH aren't there for nothing ,they diffuse the light in a closed system ,finite in evolution .

This evolution and the link with the polarisations is relevant .

In my model ,more a physical sphere is big ,less it turns ,thus our universal sphere can has the limit near 0 but not zero ....aboutthe BH thus ,its mass is important thus the rotations are linked in the ultim code of this center of the BH .Thus in logic the BH turns with a specific velocity ,all spheres turn with a specific velocity harmonized inside a beautiful sphere .All goes towards centers of mass with a specific dynamic which increases the mass in Time line evolution with very weak interactions.An important distinction is the galactical sphere volumes and the sphere of the BH ,an intersting ration exists .....

All spheres have a rule , a specific rotations system ,mass ,.....the central main codes are the key of all .Thus the center of our Universe which builds spheres inside a sphere with quantum spheres .It was so simple like that .

The BH has a specific rule ,they balance the evolmution towards the optimization.

Best Regards


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NN wrote on Oct. 11, 2009 @ 07:25 GMT
i tend to agree with the initial comment of Uncle Al. He is a personality behind the motivators and participators in this essay forum. My request for personality identification has remained fruitless thus far. He/She has the right to privaacy.

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Anonymous wrote on Oct. 12, 2009 @ 02:35 GMT
‘… It would actually be much more exciting if there were no horizon…’

The supposition that there is a horizon originates in the assumption that the mass of particles or cluster of particles is (at least partly) an intrinsic, interaction-independent property, in which case they could contract to black holes with horizons. If, however, as quantum field theory shows, a particle is as much the product of its interactions as its source, then so is its mass. If the hole’s mass is expressed as gravity, transmitted by a two-way traffic of gravitons which by a horizon is cut off to a one-way traffic, then the mass or whatever might be inside the horizon cannot be expressed outside of it, and wouldn’t exist to an outside observer so wouldn’t be part of his universe, so its horizon diameter would be zero. Though particle clusters certainly can contract to an infinite density, every cluster has a finite density, the wavelengths it expresses its mass in are of accordingly long wavelengths.

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Terry Padden wrote on Oct. 14, 2009 @ 06:18 GMT

Someone should tell you that Uncle Al is Alan Schwartz; and he has submitted an essay. Have a look at it. As you recognise, whatever/whoever else he is, he is a personality.

Please don't tell him it was me that let his secret out.

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amrit wrote on Oct. 15, 2009 @ 17:06 GMT
Dear Thomas

I would say: In centre of black hole curvature of timeless quantum space is infinitely big as space-time is a math model merely. In black hole mass transforms back into quanta of space. In AGN quantum space transforms into elementary particles. This flow is in a permanent equilibrium.

you can se more about he subject on

yours amrit

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B N Sreenath wrote on Oct. 26, 2009 @ 17:31 GMT
Dear Ted & Thomas,

You people seem to think that Black-Hole is a region of dull activities;but it is not so,for it is a region where unimaginably 'diabolical' events take place. In which,gravitation and electro-magnetism are unified and thereby both being inseperable part of the 'Quantum-Gravity' force. To cognize this ,please,go through my article on 'Quantum-Gravity'in " "".

Thanking you

Best regards

B N Sreenath

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NN wrote on Oct. 31, 2009 @ 15:17 GMT
All the talk of quantum gravity explaining away the behavior of black holes appear to me insufficient, as mysteries about black holes huge in size as also tiny liitle ones will become difficult to reconcile. I for one hold that there are some secrets left to be unrivalled yet about the facets of gravitational field that is the oldest field to emerge in the universe and it has still defied unification with the other 3 known fields. we need to understand the early universe of first billion years more through accurate and precise cosmic measurements, specially from outer space away from earth, before we may understand gravity's hidden facets. it is my hunch open to criticsm and scrutiny, as i am a mere novice to both cosmology & mathematical physics.

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Eckard Blumschein wrote on Nov. 4, 2009 @ 23:07 GMT
Dear Thomas Sotiriou,

Because I agree with Terry Padden, I am looking in vain for your reply.


Eckard Blumschein

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anonymous wrote on Feb. 9, 2010 @ 17:14 GMT
Infinite curvature? how so, yet only a straight line has no end or beginning (infinite) and curves comes around to a sure end (finite)?

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