Why would the LHC create a black hole?

[jajrussel]

Big things and little things don't work the same. From what I understand this has always been the problem. Black holes seem to require a lot of mass focused on a central point under a lot of preasure. How does the LHC put these three things together?

[insane_alien]

blackholes require a certain density for the mass(or even just energy.) this density must be sufficient that the escape velocity exceeds the speed of light. the LHC should be capable of creating those conditions by putting many many particles and a lot of energy in the one spot at the same time.

 

big things and small things don't work the same, but we kno ho both big things and small things work. so its cool.

[jajrussel]

I don't know that I ever introduced myself. My name is Joe. I live in Delaware. Theoretical Physics is not a new interest to me, however I tend to be a slow learner due more to an attention deficit than anything else. Well, at least that is what I choose to believe. I don't have to admit to being ignorant. I tend to make the fact obvious, often. Yet, I am admitting it anyway simply because I don't want anyone to think that I am under some allusion that I am, what I am not. I am just a thinker. I can't seem to think any faster than I can talk, and I tend to talk slow enough to annoy people. So, I needed a little time to think about your reply to my question.

 

I am not fully aware of how the LHC works. My understanding is that there is acceleration, then a collision. I would expect obliteration, ( I am not imagining the world coming apart here, only a couple of small pieces of it ), and a large amount of energy in a small space for a very short period of time. I can imagine this energy feeding an existing black hole, but I'm having difficulty imagining conditions being created for the formation of a black hole. None of the mass is moving in the right direction before, or after impact. During impact, well the spread of impact seems too wide. So I am assuming the assumption is a collapse of enough mass to form the black hole.

This, almost, seems imaginable, except that most of the energy is due to acceleration. The sudden collision should result in enough force to break the particles. Inertia is impossible to maintain, directions are going to change. At this point it seems, for a reason I haven't pinned down yet, that I should hope that most of the energy gained through acceleration is used affecting the direction changes. What is left is initial mass, somewhat spread out, and possibly still changing shapes and directions. I can imagine hot and cold spots, vortexes forming, swirling bits of matter, that break down as they run out of energy, but still spread to far to form a black hole. Well, this is the way I imagine it.

Personally, I am leaning toward the thought that they have a better chance of turning lead ions into gold, but my mind can be changed.

[Severian]

Our theories of physics tell us that the strength of forces change with energy. For example, the strong force gets stronger at lower energies, which is why quarks are confined within particles like the proton.

 

Given what we know about gravity, at low energies it is very weak (much weaker than the other forces), but we expect it to become strong at around 10¹⁹ GeV (called the Planck scale). If we collide particles at this energy, then the force of gravity would be so great that we might rip space-time and create a black hole.

 

Now, the LHC will hopefully collide protons of 7 TeV each, giving a total energy of 14 TeV (14,000 GeV). However, protons are composite objects, and it is really the gluons inside that will collide, which typically have about 600 GeV energy each, though some can be much more energetic. So the highest energy collisions at the LHC will be a few thousand GeV.

 

This is about 16 orders of magnitude too low to make a black hole, according to our expectations.

 

However, there is another theory which suggests that gravity might not be so weak at low energies after all. It might just appear weak because the force is 'leaking' away into extra dimensions. Normal particles are forced to live in our usual 4 dimensions, but gravitons can travel in more. A gravitational mass is therefore radiating its gravitons out into these extra dimensions, so gravity doesn't effect us as much and may appear weak.

 

If this is true, the real Planck energy, where gravity becomes strong, could be substantially lower than we thought. If it happens to be as low as 1 TeV, we could then potentially create black holes at the LHC.

 

This would require something of a conspiracy since the extra dimensions would have to be just right to make the Planck energy 1 TeV. Also, if we had had this theory of extra dimensions years ago, we could have made the same claim of any collider ever built (since you could potentially engineer the extra dimensions to give you any Planck energy you like).