Still don’t get it. The LHC operates at energies below cosmic rays. Cosmic rays do not produce blackholes we can detect therefore the LHC is more dangerous than cosmic rays?
[QUOTE=Colophon]
Did you hear abut the dyslexic guy who turned up for work at the LHC?
Never mind… 
[/QUOTE]
I always suspected the LHC is just a frot for the Illuminati.
[QUOTE=Cervaise]
Hey, if you’re really looking for something to be scared of, consider the following: There is a non-zero chance that you will, suddenly, instantly, randomly, experience quantum tunneling to another location in the universe. You will disappear from wherever you are right now, and you will reappear somewhere else entirely. Given the distribution of matter in the cosmos, it is overwhelmingly likely that you will find yourself in the vacuum of deep, deep space, way, way out there, not just between stars but between galaxies. And there is nothing you or anyone else can do to prevent this from happening, or even to get any kind of warning about it.
[/QUOTE]
Yes, yes, - but will I be able to get a refund on my SDMB subscription?
Mini Black Holes have really tiny event horizons, right? So it’s not like the thing will go around sucking massive swaths of the earth into it as it floats around. The thing is tiny. I don’t know how to calculate the rate at which it will draw matter into it, but I’m betting it would take thousands, maybe millions of years to make a noticeable difference.
Who knows what else will happen in such a time frame?
-FrL-
[QUOTE=Frylock]
Mini Black Holes have really tiny event horizons, right? So it’s not like the thing will go around sucking massive swaths of the earth into it as it floats around. The thing is tiny. I don’t know how to calculate the rate at which it will draw matter into it, but I’m betting it would take thousands, maybe millions of years to make a noticeable difference.
Who knows what else will happen in such a time frame?
-FrL-
[/QUOTE]
Must resist. Must… resist. No, can’t, can’t resist…
Won’t somebody think of the children!
[QUOTE=Ludovic]
I always suspected the LHC is just a frot for the Illuminati.
[/QUOTE]
Never frot the Illuminati. Strange notions may rub off on you.
[QUOTE=Argent Towers]
So a small black hole could actually exist on Earth for a period of time without destroying the stuff around it? What’s the longest that it could exist before it destroyed everything?
[/QUOTE]
In the haste of everyone to show off how superior their science knowledge is, nobody has answered this question.
At what size does the hawking radiation of a black hole exactly match the incoming matter at a given density (assume density at the earth centre for simplicity sake)?
A couple of perhaps relevant points:
-
The collision products at the LHC will be moving at significant fractions of the speed of light – far from stationary. And since it is a proton-proton collider, the quarks are what do the colliding, and each quark will be carrying at any given moment some random fraction of the proton’s momentum, so the (interesting part of the) collisions aren’t zero momentum anyway.
-
Blindly applying the GR result: a 14 TeV/c[sup]2[/sup] black hole would evaporate away in something like 10[sup]-85[/sup] seconds.
[QUOTE=Pasta]
- Blindly applying the GR result: a 14 TeV/c[sup]2[/sup] black hole would evaporate away in something like 10[sup]-85[/sup] seconds.
[/QUOTE]
Damn. I blinked. Could we do it again?
[QUOTE=Frylock]
As you’ve probably heard before, virtual particle/antiparticle pairs spontaneously appear (and then almost immediately disappear) all the time, pretty much everywhere. … fact it’s called Hawking radiation.
Eventually, the hole loses all its energy this way. It evaporates…
[/QUOTE]
Here’s a sort of restatement of your post.
Virtual particles are not real particles. They exist on borrowed energy and must quickly annihilate and repay this energy. However, the extreme tidal gravitation of a BH can pull them apart with enough force that they gain enough energy to become real long lived particles, and at the same time pay back the energy debt to the nearby negative energy regions of space.
So when the hole captures one of these now real particles, it in effect radiates the other one. It has therefore supplied enough energy to create two particles, but only gets the energy of one back. Thus it loses mass.
When you talk of positive and negative energy you have to understand that this is not referring to the intrinsic energy of the particles itself, but instead to their potential energy with respect to the holes gravitational field. Negative energy does not enter the BH.
ETA Sorry for all the energies there. I was in a hurry.
I have to say, I feel pretty reassured by the very intelligent responses I’ve gotten here. Thanks to all who posted.
[QUOTE=Exapno Mapcase]
Science disasters don’t. When was the last science disaster? They don’t happen for two good reasons. 1) Mostly they can’t happen. 2) Scientists are a zillion times more responsible about their work than any other class of workers.
[/QUOTE]
I don’t know, I can think of at least two disasters.
[QUOTE=WoodenTaco]
I don’t know, I can think of at least two disasters.
[/QUOTE]
Disasters? They worked didn’t they?
[QUOTE=Aioua]
Does anyone know if we had an earth-sized lump of neutronium (which is the densest thing I can think of other than a black hole)
[/QUOTE]
But then, you haven’t met my brother yet…
I’m sorry…
[QUOTE=Ring]
When you talk of positive and negative energy you have to understand that this is not referring to the intrinsic energy of the particles itself, but instead to their potential energy with respect to the holes gravitational field. Negative energy does not enter the BH.
[/QUOTE]
I require further clarification.
-FrL-
[QUOTE=WoodenTaco]
I don’t know, I can think of at least two disasters.
[/QUOTE]
A bomb, of whatever type, yield, or destructive ability, is a planned event.
Chernobyl was a disaster. Yet, Chernobyl occurred solely because the USSR, alone of all the nations in the world, chose to save money at its nuclear facilities by not including a containment shield.
This was criminally irresponsible. And fatally stupid. And any other adjectives you want to throw at it. However, it is hard to see how anyone can make a case that this was a science disaster. A bureaucratic idiocy, yes. Possibly an engineering failure. But nothing that science did caused this to happen. And despite the inherent idiocy, it only happened once in the entire lifetimes of all the reactors in the Soviet nuclear industry. (Three Mile Island, before anybody brings it up, is in no way comparable.)
As I said before, I can’t think of any actual science disasters that are large scale. Individual deaths in the laboratory, yes. Disasters, no. They are the stuff of movies and television, not the real world, except for the world of scary, misleading headlines.
I don’t know the exact answer to this question, but I am sure that the size of a sustaining black hole is many, many powers of ten larger than any black hole that the LHC is capable of making.
Again, the point is that a black hole has only its native gravity to work with. It has to absorb real particles to balance the loss of energy from the virtual particles. An LHC-size black hole is so much smaller than any individual real particle that no positive balance is possible. It’s like asking how large a mosquito sucking on your blood has to be before it winds up outweighing you.
Just wanted to let you know that someone got this pun. Vive l’France!
[QUOTE=Frylock]
I require further clarification.
-FrL-
[/QUOTE]
I’m really rushed but here’s a quick and dirty.
I’m going to use ridiculous numbers, and simplifications to make it easy to see what I’m trying to say.
Let’s say we have a couple of virtual particles pop into existence in the vicinity of a BH.
The hole’s immense tidal gravitation rips them apart in the radial direction, and imparts enough energy to satisfy both the local area energy deficit and to make the virtual particles real.
Let’s now say one particles position is 10m and the other’s position is 0m from the hole’s event horizon.
The average potential of the two particle system is the energy of the center of mass at 5m.
So we now have one particle with positive potential (10m-5m) with respect to the average energy of the system and one with negative energy (0m-5m).
Obviously the one with the negative energy will fall into the hole and the one with positive energy will escape.
But you have to keep in mind that the intrinsic mass energy of each particle remains equal and positive.
[QUOTE=WoodenTaco]
I don’t know, I can think of at least two disasters.
[/QUOTE]
You’ve not going to go after the chemists for Dresden? :rolleyes:
Well, apparently, not only are we dooming all life on Earth, but the entire universe as well.
:eek:
Yeah, well what has the universe done for US lately? Not a damn thing. I say we blow it up. Might be aliens er non-Republican Baptists er sumptin’ out there 'n the sooner we squash 'em the better. Jesus hates aliens.