Mini Black Holes

Captain Kremmen

Captain Kremmen

All aboard, me Hearties!
Valued Senior Member
Only a few weeks to go now before the CERN Large Hadron Collider is due to start bashing particles together.

It may produce mini black holes, which will give support to theories which suggest the existence of extra dimensions. There is virtually no chance of us getting sucked into them, as they will disappear quickly and violently, (for their size). Could be a renaissance for physics.

From Wiki
Six experiments (CMS, ATLAS, LHCb, TOTEM, LHC-forward and ALICE) are currently being built, and will be running on the collider; each of them will study particle collisions under a different point of view, and with different technologies.

Any thoughts on this.
 
Captain Kremmen said:
There is virtually no chance of us getting sucked into them ...
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Is that the same as saying there is a chance? "virtually no chance" means to me a chance. Do you know how to calculate that chance? If it is not zero, and if we can quite surely also say it is not 100% certainty, then how do you calculate that chance?
 
He means there is a very low chance. The chance coming from our understanding and calculations on black holes being incorrect. (I assume)
 
Walter L. Wagner said:
Is that the same as saying there is a chance? "virtually no chance" means to me a chance. Do you know how to calculate that chance? If it is not zero, and if we can quite surely also say it is not 100% certainty, then how do you calculate that chance?
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Thanks Walter.

Good question, but I hope it will start another thread.
You are just the kind of person I hoped would contribute to this thread.
I hope that in this thread conjecture will be allowed laxity, because we are at a juncture where marvellous discoveries may be made.
We are entering a period in theoretical physics which for both physics and astronomy is unprecedented. Possibly.:)

If the experiments do produce mini black holes, then the follow-on experiments using these phenomena will undoubtedly lead to a new understanding of our universe.

As regards arguing with people, I am afraid that my mathematics stretches to algebra and no further. I may interject if I feel that the argument requires explanation for the layman, but otherwise I'm going to have to leave the science to others.

I would like to see discussion on the individual experiments. I haven't looked them up to see what they are, but ALICE is an intriguing name.
What wonderland is this designed to explore?

As regards the possibilities of black holes whipping us into oblivion, I would like to request from the moderator that this is made the point of a different discussion.
 
I have a (now years old) SA issue which discusses the ATLAS and ALICE experiments in some detail, with those nice color diagrams they always have. And the others of course.

If I can dig it up from whatever corner it got stashed in, it's a good overview of the LHC and why it got built. But there's probably heaps of articles all over the web, too.

Unfortunately, although it's kind of aimed at the layman, it sure helps to know what a meson or a muon or pion is; the number of collisions will be so large that computers will "scan" for interesting events and discard everything else. I remember how the raw information from the detectors will be the highest density of information ever produced by an experiment (the LHC as a whole).

The way the detectors compute trajectories is one thing I recall about the ATLAS experiment, which uses strips of semiconducting material, laid end-to-end in staggered formation.
Apparently, they would need to disassemble the entire ATLAS detector to replace even one of these babies, so it took awhile to install and test them all. They really, really wanted to get it right.
 
"Digging it up"
Sounds like a chore. Old News.
I've only heard about it in the last week and I'm all fired up.
 
How does the evaporation escape the strong curvature produced by a black hole? Even photon are driven back by the strength of the sun, and when concerning black holes, evaporation might not excape at all.

Of course, this depends on whether Hawking Radiation exists. Even to say it didn't is enough to send a shiver down my spine.
 
I hope that in this thread conjecture will be allowed laxity, because we are at a juncture where marvellous discoveries may be made.
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We'll see how far it gets :) If people can separate solid science from pseudoscience, then it can stay here indefinitely.

What we know:
->Hawking radiation exists. It is a semi-classical computation, and no full theory of quantum gravity is needed. The metric at the horizon is smooth, and an infalling observer wouldn't even notice that he has crossed an horizon.
->The decay time for a black hole goes like its mass. This means that decay via Hawing radiation is very long for large black holes and very short for small ones.
->If we produce black holes at LHC, they will be very small, and decay very quickly.

I would also point out that, if we are able to produce black holes at LHC, we have probably produced at least one black hole at FermiLab, in the billions upon billions of collisions that have happened there since it opened. Because the probability for producing one is so low, there has been no ``discovery'' there, because we need a large number of events to do statistics on.

Further, since AUGER has been on (a couple of years), we have seen ~15-20 events in the atmosphere with energies FAR in excess of anything that will be available to us at LHC. The collision energy at LHC is on the order of 10^5 GeV. There have been events in the atmosphere whose collision energy is on the order of 10^12 GeV. So if we were able to produce black holes at LHC, AND they didn't decay via Hawking radiation, then we would have already been eaten by a trans-plankian black hole sometime in the past four billion years.

So unless someone can present an argument why these reasons aren't valid, then you shouldn't listen to them because they are a crackpot.
 
Captain Kremmen said:
Only a few weeks to go now before the CERN Large Hadron Collider is due to start bashing particles together.

It may produce mini black holes, which will give support to theories which suggest the existence of extra dimensions. There is virtually no chance of us getting sucked into them, as they will disappear quickly and violently, (for their size). Could be a renaissance for physics.

From Wiki
Six experiments (CMS, ATLAS, LHCb, TOTEM, LHC-forward and ALICE) are currently being built, and will be running on the collider; each of them will study particle collisions under a different point of view, and with different technologies.

Any thoughts on this.
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I guess if we can get answers we can always risk the existance of the entire planet... :shrug:



:D
 
BenTheMan said:
So unless someone can present an argument why these reasons aren't valid, then you shouldn't listen to them because they are a crackpot.
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The black holes are coming!!! Run for your lives!!!!!!
:runaway::runaway::runaway:
 
BenTheMan,
We'll see how far it gets If people can separate solid science from pseudoscience, then it can stay here indefinitely.
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OK. I'm sure Walter will want to weigh in when he has the time, but I will start it off.
What we know:
->Hawking radiation exists.
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That is a statement presented as a fact. Can you provide evidence? Which type of Hawking radiation do you know exists? I'll assume thermal radiation from the micro black holes theorized by quantum theory as that is what this thread is about.
It is a semi-classical computation, and no full theory of quantum gravity is needed.
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Yes, the computation is a thermodynamics computation in which gravity is essentially ignored.
The metric at the horizon is smooth, and an infalling observer wouldn't even notice that he has crossed an horizon.
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Whoops, you have gotten confused already. An observer falling into a macro-sized Schwarzschild black hole of GR wouldn't know when he passed the event horizon. The micro black hole of quantum theory (if they exist) is a different animal. Thermal radiation (Hawking radiation in the form of heat) escapes the micro black hole and a tiny observer approaching the horizon would definately feel the heat. The classical black holes of GR were assumed to have zero temperature as thermal radiation could not escape through the event horizon. See the difference?
 
I have to say, we do not know from any experimental evidence that Hawking Radiation exists Ben, so i would have to disagree. Since mathematics has been created to show special classes of black holes ''extremal black holes'' could exist that don't thermoradiate, then we have quite a lot of confusion don't we?

Can extremal black holes exist so that they gobble up matter but don't radiate? Of course they could. There is no reason we can say either way until we foolishly endeavour into creating our own to observe.
 
Reiku said:
I have to say, we do not know from any experimental evidence that Hawking Radiation exists Ben, so i would have to disagree. Since mathematics has been created to show special classes of black holes ''extremal black holes'' could exist that don't thermoradiate, then we have quite a lot of confusion don't we?

Can extremal black holes exist so that they gobble up matter but don't radiate? Of course they could. There is no reason we can say either way until we foolishly endeavour into creating our own to observe.
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There must be a limitation on the speed at which they grow.
How long would it theoretically take a micro black hole to double in mass if it lost no mass through radiation?
 
Yes, the computation is a thermodynamics computation in which gravity is essentially ignored.
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The gravity is ignored because it is weak and can be consistently ignored. Hawking radiation exists because it is a prediction of classical physics, so I don't understand why people are confused, unless they don't understand the calculation.
 
Whoops, you have gotten confused already. An observer falling into a macro-sized Schwarzschild black hole of GR wouldn't know when he passed the event horizon. The micro black hole of quantum theory (if they exist) is a different animal. Thermal radiation (Hawking radiation in the form of heat) escapes the micro black hole and a tiny observer approaching the horizon would definately feel the heat. The classical black holes of GR were assumed to have zero temperature as thermal radiation could not escape through the event horizon. See the difference?
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Thank you for the primer, but hopefully it was clear that I was talking about macroscopic black holes. And either way, if you're not convinced that the semi-classical computation should hold even for very small black holes, you should be convinced by the fact that there are a few events in the atmosphere with energies FAR in excess of what we'll be able to produce at LHC, so if the Planck scale is at a TeV, then we would have already been eaten by a black hole produced in our atmosphere by ultra high energy cosmic rays.

Please rebut the main points of the argument as opposed to the minor details. If you want to argue that the semi-classical computation shouldn't hold at small distances, then please show me where the calculation breaks down. Hawkings original calculation can be found here.
 
BenTheMan said:
The gravity is ignored because it is weak and can be consistently ignored. Hawking radiation exists because it is a prediction of classical physics, so I don't understand why people are confused, unless they don't understand the calculation.
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Are you stating an event horizon doesn't develope because gravity at the Schwarzchild radius is too weak to form an event horizon? Why are the 'micro black holes' called black holes if they don't have an event horizon? And Ben, there is a difference between 'a prediction' and 'it exists'. No, I can't do the calculations for Hawking radiation, can you? Are you even aware that the frequency of the radiation must go through an intermediate phase in which it must be much higher than plank frequency? I am speaking of the thermal radiation by which micro black holes are supposed to evaporate, of course. Micro black holes don't evaporate through the pair production mechanism proposed for large black holes.
 
''Micro black holes don't evaporate through the pair production mechanism proposed for large black holes.''

Is that true? I never knew that.
 
Are you stating an event horizon doesn't develope because gravity at the Schwarzchild radius is too weak to form an event horizon?
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No, I'm saying that the only way you would know you were passing an event horizon is to know something about the global causal structure of the space-time.

[Why are the 'micro black holes' called black holes if they don't have an event horizon?
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see previous. The horizon is only aparent if you know something about the causal structure of the space-time that you;re living in. Other than that, there's no way that you'd know if you fell past an horizon.

And Ben, there is a difference between 'a prediction' and 'it exists'.
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Sure there is. But the calculation of Hawking radiation is entirely classical, and can be done without evoking any quantum arguments. This is why it is so interesting.

No, I can't do the calculations for Hawking radiation, can you?
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Yes, or, at least I've done it before. I have the notes written down somewhere. Essentially you put a scalar field in a space-time that contains a black hole. You write down creation and destruction operators at asymptotic past and creation and destruction operators at asymptotic future for the scalar field. Then you find that the two sets of operators are not the same. Then you realize that there is a way to relate the two sets of operators, called a Bogolyubov transformation. The implication of this transformation is that there is a net particle production.

You can read about it in this set of lecture notes : http://arxiv.org/abs/0803.2030, which look te be very pedagogical.
 
Micro black holes don't evaporate through the pair production mechanism proposed for large black holes.
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Are you just saying this or do you have some proof?
 
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