I wandered across a wicked smaht explanation about why the Large Hadron Collider won't ZOMG make killer Black Holes n' stuff, over at Atomic Nerds (Yes, I know this post is 2 years old. Yes I know I'm slow. Work with me.)
Basically, Stingray's cipherin' leads to the conclusion that a proton is eleventy zillion times bigger than a LHC-created black hole could ever hope to be. Marko was disappointed, because that's WAY too small for Dragons to fly out of, and Marko said he was promised Dragons. But that's not my point.
Here's the physics nerd question: since any such black hole is wicked, wicked small, don't quantum effects come into play? Particularly the Uncertainty Principle, which means that the actual location of the event horizon would be unknowable?
IIRC, Steven Hawking gave a talk back in the '70s at Cal Tech where he said that because of these Quantum Effects, tiny black holes would radiate energy away. Basically, a quantum of energy would find itself immediately below the event horizon, and then POOF the event horizon moves (well, not really, but the math makes my head hurt; its location can only be approximately known, and it fluctuates around a mean). Since the energy quantum now finds itself above the event horizon, it can escape the black hole.
Hawking called these little Black Holes "quantum" Black Holes, and said that they "evaporate" because of the energy loss. So wouldn't any LHC created Black Hole evaporate? Isn't Stingray's argument even stronger?
All right, I'm done geeking out, but someone really needs to pay Stingray his $500 ...
That's what I've heard--basically the black holes will exist for a tiny fraction of a second before "collapsing," if that makes any sense. So the physicists will get to watch really cool things happen, but it won't destroy the universe. It seems to me that if it was that easy to destroy the universe, someone would have done it by now.
ReplyDeleteA pal with lots and lots of post doc stuff in astrophysics tried (and failled miserably) to explain the evaporation thing to me.
ReplyDeleteApparently all black holes emit Hawking radiation, which is greater in smaller balck holes than large. Since this emission has to result in a loss of mass/energy from the black hole, smaller ones should evaporate completely rather quickly.
ReplyDeleteThe Hawking radiation is probably best describd as a knd of "quantum heat", which sounds more like a late-night Skinemax movie than anything else. It's like a black hole is a perfect Black Body in quantum terms - even a normal Black Body (absorbing all energy and reflecting none) radiates heat energy with a particular pattern, so at a quantum level black hole emit Hawking Radiation with a partcular pattern. Or at least they are supposed to.
Such findings are a consequence of demanding that all physical laws are universal. All objects not at equilibrium radiate in at least a black body way, except black holes - nothing gets out. How could something get out? Maybe it gets out at the quantum level. That means black holes DO radiate something, somehow, eventuually, and universal physical law is appeased. If it's true.
Also, here's a neat factoid: the LHC energies are still much less than the most energetic cosmic ray impacts in the earth's atmosphere.
ReplyDeleteAnother neat factoid: solar flares on the sun are so energetic they make _kilograms_ of antimatter.
Makes the LHC look like a firecracker.
NMM1AFAN got what I was going to say, which is the most accessible argument in favour of not freaking out I've heard on the subject.
ReplyDeleteJim
You're right about the uncertainty principle--simplifying a bit, since the location of a particle is uncertain, the smaller the "box" you try to confine a particle in, the higher the probability that the particle will suddenly be outside of the box. Since the kind of black hole we're talking makes an exceedingly small box, the matter inside will leak out very quickly. The leakage is called Hawking radiation, and will deplete any black hole the LHC could make in a tiny fraction of a second. In effect, the black hole will explode into a shower of fundamental particles as quickly as it is created.
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