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No Earth-imploding black holes at LHC this decade. Probably.

While (some of) the world watched the Large Hadron Collider power up, fault, power up again and ultimately land its first 7 TeV collisions, others may have gripped their armchairs tightly, waiting for the planet-destroying black hole that some claim the LHC is capable of creating. As one might be inclined to notice, the Earth has made it through the ordeal just fine.

However, whether these doomsday black hole concerns are credible or not, a pair of scientists from Princeton University and the University of British Columbia at Vancouver have been delving into the relativistic physics calculations just to see what might really happen. Matthew Choptuik from UBCV and Frans Pretorius from Princeton have done the grunt work to solve field equations related to soliton collisions at specific energies.

"Our calculation produced results that most were expecting, but no one had done the calculation before. People were just sort of assuming that it would work out. Now that these simulations have been done, some scientists will have a better idea of what to look for in terms of trying to see if black holes are formed in LHC collisions," explained Choptuik.

Based on string theory and its extra dimensions, Choptuik and Pretorious concluded that high-energy collisions at the LHC could indeed form black holes -- but the chances of them destroying the world are pale even in comparison to the chance that they would actually be detected by LHC equipment while they exist.

Of the events, Choptuik says, "Some are already taking this very seriously. However, I don’t think that we are likely to actually see any black holes at the LHC, even if it is possible."

Rather than directly observing such a formation, he explains that to confirm the existence of the fleeting matter-energy magnet, LHC scientists will have to study the debris from the collision rather than the particles that instantaneously exist and then disappear. A typical collision would leave jets of debris while the short-lived black hole would produce a more spherical pattern.

The duo's findings have been published in the journal 
Physical Review Letters, titled "Ultrarelativistic Particle Collisions."



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RE: Black Holes
By Smilin on 4/7/2010 11:55:32 AM , Rating: 2
Going to take a shot at answering, please forgive my mauling of physics..

So black holes cause such a high energy disturbance near their event horizon that particle+antiparticle pairs are formed. In most cases these two immediately collide and annihilate each other. Every so often though they are *just* near the event horizon so that one falls in and the other remains without annihilation. In this way mass can actually "leak" out of a black hole and they'll eventually evaporate.

The rate of evaporation is related to size. Very large black holes (like center of galaxy ones) can take many times the age of the universe to evaporate so basically they don't. Very tiny ones evaporate almost immediately.

The ones at the LHC would likely evaporate before they hit the ground, let alone reached the core of the earth. The size of its event horizon means it's unlikely to collect any mass at all before it dies let alone enough to make it's event horizon grow enough to reach nearby atoms.

So there you have it. I know my rough understanding is correct by I've surely mauled the details since I learned this about a decade ago.


RE: Black Holes
By freeagle on 4/7/2010 4:09:40 PM , Rating: 2
This is one explanation of the process. There are other possibilities:

1. through quantum tuneling ( which I'm not very familiar with yet ), a particle can escape from the inside of the event horizon
2. due to Heisenbergs uncertainty principle, the virtual particle can have for a very short period of time speed higher than the speed of light, enabling it to escape from the inside of the event horizon

All 3 explanations describe the same process with same results


RE: Black Holes
By SPOOFE on 4/7/2010 5:02:19 PM , Rating: 2
quote:
1. through quantum tuneling ( which I'm not very familiar with yet ), a particle can escape from the inside of the event horizon

No, quantum tunneling does not indicate anything like that could happen.

quote:
2. due to Heisenbergs uncertainty principle, the virtual particle can have for a very short period of time speed higher than the speed of light, enabling it to escape from the inside of the event horizon

No, Heisenberg's principle does not indicate anything like that could happen. The only times we've witnessed particles exceed "the speed of light", it was locally, ie- situations in which light particles have beens slowed down dramatically. "The Speed Of Light", or the speed of light in a vacuum, or C, is a mathematically defined upper limit of velocities, supported by numerous experiments and observations and calculations; similarly, an event horizon is a mathematically defined region of intense attraction that matches C, resulting in the "light can't escape" descriptor.


RE: Black Holes
By freeagle on 4/7/2010 5:24:52 PM , Rating: 3
That's not true.

1. Quantum physics does not tell the exact position of a particle, it works only with probabilities. That means that particle that "is" just under the event horizon has non-zero probability of being outside of it.

2. Heisenbergs uncertainty principle states, that for a very short duration less than Planck's constant, the law of conservation of energy and momentum does not hold true. This allows the particle for this duration to obtain speed higher than the speed of light, allowing it to escape from the event horizon.

I can point you to the article and discussion I'm gathering the info from, but it's in czech language. I'm sure you can find something in english as well ( http://hp.ujf.cas.cz/~wagner/popclan/vakuum/vakuum... http://www.osel.cz/index.php?obsah=6&akce=showall&... )


RE: Black Holes
By camylarde on 4/8/2010 9:51:20 AM , Rating: 2
... and i believed that the particle-antiparticle pair is formed in a pure vacuum on regular basis, followed by their immediate annihilation.

I understood that Hawking's radiation is explained by this:

particle and antiparticle forms in vacuum just outside of the event horizont and as one of these two particles enters the black hole sooner than the other one manages to, the other one actually is being shot away from the black hole while the black hole loses the mass equivalent to the particle being "created".

Bottom line is this particle is in no way related to the contents of the black hole itself, and the only representation of it's creation is the mass loss to the black hole equivalent to the particle's mass.

I might be wrong though.


RE: Black Holes
By freeagle on 4/8/2010 10:14:50 AM , Rating: 2
Since mass is energy ( e=mc^2 ), the black hole looses energy with every such paticle it sucks in. When a virtual particle-antiparticle pair is created, it's done so out of thin air. You need to somehow pay back the energy that went into creating them. Under normal circumstances, this is paid by their imminent anihilation. But when one of them is sucked into the black hole, it's that black hole that has to pay for the energy deficit, so it looses part of it's total energy. And since it does not have an infinite amount of it, it will cease to exist over time.


RE: Black Holes
By kenthaman on 4/13/2010 2:04:10 PM , Rating: 2
Two thoughts on this.

First, if particle-antiparticle pairs are created at the event horizon and one-half of the pair, be it particle or antiparticle is consumed by the BH, wouldn't the counterpart likely be consumed shortly thereafter? Or is the resulting energy from unbalanced pair enough to allow the part/AP to escape?

Second, assuming that the creation of these pairs is a randomly occuring act wouldn't it be equally likely that the number of particles versus the number of antiparticles consumed by the BH would overall be equal?

Disclaimer: I am in no way, shape, or form claiming to be an expert on this subject matter. Just stating a couple of thoughts that crossed my mind based on my understanding of the Universe in a nutshell ;)


RE: Black Holes
By freeagle on 4/14/2010 12:30:46 PM , Rating: 2
quote:
First, if particle-antiparticle pairs are created at the event horizon and one-half of the pair, be it particle or antiparticle is consumed by the BH, wouldn't the counterpart likely be consumed shortly thereafter? Or is the resulting energy from unbalanced pair enough to allow the part/AP to escape?


Hmm. It's very probable that the other particle will be sucked in as well, but it's not going to be in 100% of cases. Which is enough for the BH to be loosing it's energy while not sucking in anything else.

quote:
Second, assuming that the creation of these pairs is a randomly occuring act wouldn't it be equally likely that the number of particles versus the number of antiparticles consumed by the BH would overall be equal?


I assume you think this would lead to zero net-loss of energy of the black hole. I think this should not be the case, since particles and their antiparticle counterparts have exactly the same weight and are made of the "same" energy ( there is no antienergy, or at least we think so ). This means, that it doesnt matter whether particle or antiparticle is sucked in, the black hole will always loose energy when it sucks in one of the virtual particles from pair.

quote:
Disclaimer: I am in no way, shape, or form claiming to be an expert on this subject matter. Just stating a couple of thoughts that crossed my mind based on my understanding of the Universe in a nutshell ;)


neither do I ;)


"If you mod me down, I will become more insightful than you can possibly imagine." -- Slashdot

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