posted
Pretty interesting article, although briefer than I'd like. I'll have to do some digging and see if I can't come up with something that goes into a little more detail.
Posts: 16059 | Registered: Aug 2000
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posted
smashing tiny particle would be unlikely to produce a blackhole massive enough to last dangerously long, or do much damage... I think. Gotta ask my dad...
Posts: 772 | Registered: Feb 2005
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posted
That is so freaking awesome! Now we just need to find a way to harness this power and use it against our enemies.
Posts: 9945 | Registered: Sep 2002
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posted
Well, it might explain why SETI hasn't turned up anything yet. Maybe most intelligent species get their worlds sucked into self-made black holes in the process of trying to move beyond rudimentary technologies. Posts: 6394 | Registered: Dec 1999
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Ok, it may indeed be a black hole. I don't know enough of the right kind of physics to have any idea, although I'll ask my dad about it after Shabbos.
But why is it, every time there is an experiment that shows a discrepancy from predicted values, the most fantastic and exotic notions are suggested by the researchers FIRST?
Too much energy produced. Wow, that must mean we did cold fusion!
Too many jets absorbed! Must be a black hole!
Could we, at the VERY least, please verify the reproducibility of our experiments before we publish these theories?
Sheesh, Newton waited 20 years to publish his theory of universal gravitation, because he wasn't sure.
Modern researchers would do well to take a page from his book.
posted
Reminds me of that Spiderman episode where a large blackhole formed above New York City and threatened to engulf the entire earth. I mean, don't scientists ever learn?
Posts: 722 | Registered: Jul 2004
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posted
As far as I can tell what they're saying is that though at these energy levels and mass levels, the electro-magnetic force is still pervasive, an unlocking of the pion-fields and/ nucleon bags is indicative of a black-hole gravity well.
posted
If this guy is right, it does seem that the explanation for the mini-black hole depends on string theory. That would be a huge discovery. But most string theory calculations are sloppy in one way or another, so it's hard to trust a result that hasn't yet been peer-reviewed. I can't judge any of the details myself -- I know nothing about strings or branes.
Posts: 4600 | Registered: Mar 2000
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posted
But, rivka - if they waited a decent interval before publishing, what would the rest of us have to freak out about? Posts: 5609 | Registered: Jan 2003
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posted
Apparently the energy scattering patterns fit a loose model of Heisenberg's prediction and the fireball formation would be consistent with the prediction of a pion analogue black hole, also the temperature readings were kind of consistent with Hawking's prediction (that resulted in the theoretical discovery of Hawking radiation). Finally, the existence of a consistent fireball (exponentially decaying yes, but without hard jet release) shows that either an extreme amount of energy was placated in a short time and distance (which they think is impossible) or a black hole was formed from the energy (pion black hole that is) and the released Hawking radiation is then the exponential release of energy in a smooth fashion.
However, they make more than a few assumptions specifically designed to give the possibility of a black hole. Inconsistencies with equations are written off because if the black-hole does exist the equations wouldn't be fully accurate as they approach the black-hole horizon space. Plus they changed how many dimensions they were working in. I hate when people do that!
posted
Hobbes, it's not clear to me from the paper what a 'pion black hole' is. This idea of 'duality' seems to be key here -- the author mentions that the creation of free pions is 'dual' to the black hole's radiating gravitons, but I have no idea what it means for some activity in one quantum field to be 'dual' to what's happening in another. Do you know what he means by this?
Posts: 4600 | Registered: Mar 2000
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posted
Yah, I can't figure out what the dual black-hole means, but I got the impression that a pion black hole meant that the interior of one atom collapsed in on itself to form a black hole, which I suppose is different than a normal black-hole at least because then it doesn't have to break the electron exclusion rule.
Maybe he just means that the release of pions is equivalent to the "graviton release" predicted for a normal black-hole?
quote:We noticed that the Heisenberg model can be mapped to the dual A-S shockwave scattering picture even before the saturation of the Froissart bound. All we have to do is relax Heisenberg’s assumption of exponentially decaying pion wavefunction around the hadrons, and have instead the wavefunction of the A-S shockwave which is mapped to a wavefunction of the lightest glueball field. In this case however, unlike for the maximal Froissart behaviour, the dual picture is not 4 dimensional anymore, it is 10 dimensional, and we have the usual holography. This Heisenberg description of the gauge theory scattering means that the black hole being formed in the dual scattering is still mapped to a nonlinear effective field soliton, but the effective field is the lightest glueball. Above ˆER ∼ 10GeV , this description is exact, below it could be modified due to string corrections.
This paper was obviously written for other high-energy physicists, not people who don't know anything about high-energy physics (*points to self*) so really I'm kind of just adrift in this whole thing.
quote:Yah, I can't figure out what the dual black-hole means, but I got the impression that a pion black hole meant that the interior of one atom collapsed in on itself to form a black hole, which I suppose is different than a normal black-hole at least because then it doesn't have to break the electron exclusion rule.
I don't think that's it. He says that a pi soliton (which is a kind of solution to the pion field) is 'dual' to a black hole solution of the gravitational field (which I assume is a quantum field in string theory). I don't know what in particular the pi soliton would have to do with the collapse of an atom, and in fact it seems to me that in a RHIC collision you're not really dealing with 'atoms' or even nuclei any more because the energy is so much higher than the nuclear binding force (which is why you get quark-gluon plasma). Also, pions are mesons and don't obey the exclusion principle, so I'm not sure what relevance that could have.
Anyway, we're both talking out of our arses here to some degree or another. Who knows? Posts: 4600 | Registered: Mar 2000
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posted
Hobbes is right, they do make several assumptions that may be unwarranted.
quote:The solution a ≃ 1/8 is probably just due to our use of the formula (13),so we leave it a free parameter.Indeed, if a = 1, and we replace M1 by the pion mass m, by which we mean of course the average mass (m+ + m− + m0)/3, we get T =(4/π)*< m >= 175.76MeV remarkably close to the experimental value of the RHIC fireball “freeze-out” of 176MeV.[from top of pp6]
The horizon of the black hole is the limiting (“freeze-out”) surface of the pion field soliton, which emits radiation at a temperature given by (if the nonperturbative constant a=1) (20), very close to the experimental value of 176 MeV [14, 15]. Most likely there will be no singularity for this black hole.[from pp8, concluding paragraphs]
Bolds added. They calculate the temperature of the predicted/observed black hole 2 ways. One way gets T = a4M1/π (9), later they derive T ≃(M1)2/π (19) using Hawking’s original calculation of the temperature of 4d black holes of Kerr-Newman type (rotating). So a would be approx 1/8. Then they assume that a=1, and the numbers work out in their conclusion, 175.76MeV (calculated value assuming a=1) ≃ 176MeV (experimental value.)
But the a=1 assumption seems arbitrary, although they attempt to explain it:
quote:The solution a ≃ 1/8 is probably just due to our use of the formula (13), so we leave it a free parameter.
quote:I don't think that's it. He says that a pi soliton (which is a kind of solution to the pion field) is 'dual' to a black hole solution of the gravitational field (which I assume is a quantum field in string theory). I don't know what in particular the pi soliton would have to do with the collapse of an atom, and in fact it seems to me that in a RHIC collision you're not really dealing with 'atoms' or even nuclei any more because the energy is so much higher than the nuclear binding force (which is why you get quark-gluon plasma). Also, pions are mesons and don't obey the exclusion principle, so I'm not sure what relevance that could have.
You're probably right, at least about me being wrong. I mentioned the electron exclusion principle because that's a barrier a normal black-hole has to break to form, but since there's no electrons here, obviously the electron pressure is zero. ::shrug::
Yah, I may be talking out of my posterior but I still agree with Morbo, they made a lot of assumptions for the end goal of announcing a black hole.
On the other hand, who knows, maybe it really is. (Probably not though )
posted
[Before Morbo's edit, this was obviously referring to his singularities comment ]Me too! And check out this hum-dinger of a sentence:
quote:However, we should note now that we have done something not obviously right. We have extended the regime of validity of the Newtonian approximation to the interior of the black hole, where we have no justification for this approximation.
Wow-ho-ho! What are they doing sticking anything with Newton's name on it inside a black-hole anyways? That's like trying to predict what happened before the big bang using Einstein's theory of general relativity!
posted
Actually, now that I think about it, black-holes don't have to have singularities if they form fast enough, they just need a high enough mass concentration so that there's a region of space that has a high enough gravitational field to capture light. If it forms to fast I guess the mass might not have condensed down to a singularity at that point? I don't know, but it is true that infinite density isn't required for trapping light.
quote:Also note that usual black holes have singularities, but the black holes created in this collision most likely will not. Indeed, for one thing it would be hard to imagine the brane bending analog of the black hole singularity: it would be a pinch-like singularity that seems unphysical. Also, in the field theory, a pion field singularity seems very unlikely. It could also be the case that these black holes are created and decay quickly, and the singularity cannot form.
I have no idea what a pinch-like singularity is though, or what it is that makes a pion-singularity too unlikely to be counted but a pion-black hole so likely they wrote an article announcing one.
posted
I noticed that too, Hobbes. [edit: the questionable validity of the Newtonian approximation, even the authors thought it was fisht]
BTW, even if they are forming black holes, it's not clear if a minicule-mass black hole would ever absorb enough matter to even be noticable, much less devour the entire Earth. If Hawkings radiation theory is correct, energy will flow out as mass/energy flows in, so they will probably just "evaporate." Even if they don't evaporate, shock waves and turbulence at and near the event horizon will severely limit a small black hole's ability to devour large amounts of mass.
So, don't panic, go back to waiting for a comet strike. Morbo
posted
Yah, a black-hole has to have a much bigger event-horizon before it becomes a worry. Especially since the Hawking radiation evaporation rate is inversely proportional to the mass of the black hole, anything on such small scales will destroy itself orders of magnitude before the gravity waves even reach the center of the earth!
quote: Especially since the Hawking radiation evaporation rate is inversely proportional to the mass of the black hole
True. If it gets enough mass going before it evaporates, it could release significent gamma radiation though. I don't think that will happen though--most likely these will be mayfly black holes with lives of only tiny fractions of a second.
Posts: 327 | Registered: Oct 2003
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posted
Yah, but all the energy that comes out had to have been put in, and when we're talking about black holes created in particle accelerators that mans only as much energy as is already used by the accelerator plus mc^2, and m is pretty much going to have to be only a few atoms.
posted
Assuming they don't absorb any significent quantities of mass after the collision that creates them but before they evaporate, any mass that goes in will come back out as energy via Hawking's radiation (Hr).
Also, I'm not sure Hawking's has been verified via astronomical observation. It may still be just a theory, though probably correct the Hr model could be off by a considerable amount or not exist at all.
Posts: 327 | Registered: Oct 2003
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posted
But if they are as short-lived as predicted, they wouldn't even have time to make it to the edge of the accelerator tube before disappearing.
Posts: 327 | Registered: Oct 2003
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posted
Yah, it's still untested theory, but then again the idea of existence of a black hole in the collider was based on that theory so if it's wrong there probably wasn't a black-hole to begin with.
posted
Just did some googling, found this: If the usual evaporation equations apply, 10^(-25) seconds is the lifetime of a one gram black hole. www.gyre.org has some good links about RHIC-created black holes and other doomsday scenarios. This guy seems to think Hawking is unproven, and he has a whole paper devoted to what we've been discussing:"The Potential for Danger in Particle Collider Experiments":
quote: Hawking evaporation has never been tested. In several surveys, physicists have estimated a non trivial probability that Hawking evaporation will not work. [Ref. 9] My estimate of its risk of Hawking evaporation failure is 20%, or perhaps as much as 30%.
http://www.risk-evaluation-forum.org/luisada1.htm Of course, this is physics, not sure how relevent survey are. [edit:...and the source given for the surveys is the risk-evaluation forum (not really a forum)]
quote:The math of Hawking radiation is the hardest in physics, but the issue is simple. Hawking has a neat model of the black hole event horizon that shows how energy can come out of a black hole. It relies on a quantum theory that is widely accepted, but widely regarded as strange. Einstein did not believe it.
He has a point but he could do without sentances like these. Hawking radiation is certainly not the hardest math in physics (just look at string theory!) and Einstein doesn't enter in here, after all, Newton didn't hold with the special theory of relativity either.
Really though, it should certainly be taken into consideration, if Hawking radiation does work then non-evaporating black holes could pose a real threat I guess.
posted
And other physicists agree with me on the bogus a=1 assumption
quote: Other physicists say there are flaws in the calculations. For example, Nastase assumes that the value of a constant that appears in his equations is exactly 1, rather than calculating the value himself. He admits that he is guessing and says, "In physics quite often these dimensionless constants turn out to be 1."
posted
Yeah, Hobbes, I wasn't very impressed with that paper from risk-evaluation. He used a ton of exclamation marks, for one thing, not good practice in a scientific paper, even one that's abstracted from a longer paper to put on a website.
Posts: 327 | Registered: Oct 2003
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posted
Thanks, Andy. [edit:you probably noticed it too, you mentioned bad assumptions before me.]
I missed the part where they changed dimensions until you pointed it out.
I also missed this:
quote: Shuryak also points out that while the fireball cools rapidly to around half its initial temperature, Nastase's calculations assume its temperature is fixed. Shuryak is now working on his own AdS calculations that will take this into account. "Any solution must explain how the temperature evolves as a function of time," he says
from my link above And it's unproven [edit: I think] that AdS (a type of string theory) is equivilent to quantum chromodynamics (QCD), though there is precedent. QCD, as the last linked article says, in fiendishly difficult to do calculations in, requiring massive amounts of computations on supercomputers, so Nastase switched to string theory to do simpler equations he hopes will be equivilant to the skipped QCD computations.
All in all, it's an very interesting paper but unconvincing. The follow-up papers should be great.
posted
I feel pretty worried for all of the very small, instantaneous people dwelling in the particle accelerator. Those guys are doomed.
Posts: 8504 | Registered: Aug 1999
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posted
cool! now we will have a better weapon for interstellar wars, anyone messes with earthlings we make a "small" black hole just big enough to swallow their ship, or planet, as the situation dictates.
Now we just regular intyerstellar travel, and some hostile aliens (and hopefully a few friendly one), and we will be all set.
Posts: 376 | Registered: Sep 2004
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posted
"Plus they changed how many dimensions they were working in. I hate when people do that! "
me too
The good news is that they coulda created a blackhole. Using the same general theory on slightly different premises for calculation, the bad news is... ...the blackhole could have only partially dissassociated itself. And it could even now be in a pendulum orbit through the Earth. Slowly eating up matter/energy on each pass through the Earth slowly growing larger each pendulum swing becoming increasingly faster-growing as it gets bigger... WE'RE DOOMED
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Yah, a black-hole has to have a much bigger event-horizon before it becomes a worry. Especially since the Hawking radiation evaporation rate is inversely proportional to the mass of the black hole, anything on such small scales will destroy itself orders of magnitude before the gravity waves even reach the center of the earth!![[Roll Eyes]](rolleyes.gif)
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me too 
