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Black hole in LHC?

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dmitrrr
#37
Aug6-08, 06:32 AM
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humanino:
BH should already be produced in the atmosphere from cosmic rays
I agree, that the energy of a single particle from cosmic ray can be much larger
than energy of a single particle in LHC, it calms.
But there remains a concern. Namely
intensity of cosmic rays is incomparably less than in LHC.
In LHC very many particles will hit the unit area of target in one second, and as result
much more energy will hit the unit area in unit of time.
So, there could be unknown non-linear effect, which will give a BH.
Vanadium 50
#38
Aug6-08, 06:44 AM
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Quote Quote by dmitrrr View Post
So, there could be unknown non-linear effect, which will give a BH.
Only if you call this unknown non-linear effect "magic".

First, there is no target at the LHC. There are colliding beams. That's why it's called the Large Hadron Collider. Next, there are a series of discrete interactions, occurring every 25 ns. Are you trying to tell us that somehow space "remembers" that previously there was a collision there?
ZapperZ
#39
Aug6-08, 07:33 AM
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Quote Quote by dmitrrr View Post
I agree, that the energy of a single particle from cosmic ray can be much larger
than energy of a single particle in LHC, it calms.
But there remains a concern. Namely
intensity of cosmic rays is incomparably less than in LHC.
In LHC very many particles will hit the unit area of target in one second, and as result
much more energy will hit the unit area in unit of time.
So, there could be unknown non-linear effect, which will give a BH.
I think that you need to give the committee that reviewed the LHC safety a lot more credit for intelligence than this. After all, the notion of "luminosity" is a very common parameter in particle colliders. You need to look at the safety report and show that the issue that you have brought up has been ignored. Till then, your complain is rather moot.

Zz.
Varnick
#40
Aug6-08, 02:34 PM
P: 77
Particle collisions like those in the LHC happen naturally, they just aren't observed by huge detectors. Thus, if the LHC were likely to produce dangerous black holes, we would have seen this naturally occurring, no?
jms5631
#41
Aug6-08, 03:36 PM
P: 55
The energy levels produced in the LHC are only going to be a fraction of those energies produced in nature everyday from events such as gamma ray bursts and cosmic ray collisions. In a very real sense, we already use the universe as a veritable collider whose vast size amplifies the effects of cosmic events, and observe the effects of extraordinarly high energy occurances, to which the LHC pales in comparison. The fact of our continued existence is a strong confirmation of LHC's safety. However, additional safety concerns have been probed and reviewed in the CERN safety report which is exceptionally comprehensive.
buffordboy23
#42
Aug6-08, 08:48 PM
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Quote Quote by humanino View Post
No. The safety argument is that BH should already be produced in the atmosphere from cosmic rays, but we are still here.
In this scenario, the colliding particles have vastly different momenta, so if a black hole forms, its velocity is likely always greater than the escape velocity of earth.

For the LHC I would imagine that the colliding protons have a greater probability of creating a black hole whose velocity is less than earth's escape velocity, since the colliding protons will have momenta of about the same magnitude and approach from nearly opposite directions in terms of the stationary LHC frame. I think the probabilities of such a result would be very small, but possible. Does this make sense?

If this is true, I am not too concerned since the black hole would be extremely tiny and will have little gravitational effect on its immediate surroundings; its essentially a black hole with total mass no more than two protons.
H0T_S0UP
#43
Aug6-08, 09:00 PM
P: 32
Well suppose many small black holes are created and collide. Could that pose a problem? Also couldn't it be beneficial if the LHC created microscopic black holes. That way they could be studied with very little risk.
ZapperZ
#44
Aug6-08, 09:07 PM
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Quote Quote by H0T_S0UP View Post
Well suppose many small black holes are created and collide. Could that pose a problem? Also couldn't it be beneficial if the LHC created microscopic black holes. That way they could be studied with very little risk.
Actually, it does. However, after chatting with a few people who worked on the Atlas detector, they all have concluded that it will be very difficult to distinguish signatures of the creation of "blackholes" versus other events. I had a Q&A session with Tom LeCompte, was recently appointed to be the science coordinator (assistant for the first year) of Atlas. You may read both parts of my session with him here.

http://physicsandphysicists.blogspot...ome-atlas.html
http://physicsandphysicists.blogspot...-atlas_21.html

In the second part, he addressed my question if such blackholes can be identified if created at Atlas.

Zz.
Topher925
#45
Aug7-08, 11:49 AM
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Are black holes really thought of actually existing? I always thought of them as still being theory, although a highly supported theory. After all do we really have any cognitive proof that black holes really do exist other than mathematics based on empirical assumptions?
Vanadium 50
#46
Aug7-08, 11:56 AM
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Do you mean micro-BHs? No, nobody knows if they exist. Odds are they don't.

If you mean astronomical BHs, there are a number of objects that are known to be too heavy to be neutron stars or too dense to be anything but a BH.
enisys
#47
Aug22-08, 01:06 PM
P: 1
Hello, I understand that our equations have demonstrated that the microscopic black holes capable of being created at the LHC would quickly evaporate, but I was curious as to whether or not those conclusions were strongly based on the assumption that black holes are infinitely dense. If black holes happen to NOT be infinitely dense, would the results be much different??
Orion1
#48
Aug22-08, 01:58 PM
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I have already calculated how much time is required for a classical 'stable' micro-singularity to consume one Iron nucleus in Terra's core at 1 Tev:
[tex]\boxed{\tau_b = \frac{4 m_{Fe}}{3} \left(\frac{E_b}{\hbar c} \right)^2 \sqrt{\frac{r_e^7}{2 G m_e^3}}}[/tex]

[tex]\tau_b = 12331.540 \; \text{s}[/tex] = 3.425 hrs.

Time required for a classical 'stable' micro-singularity to consume one proton in Sol's core at 1 Tev:
[tex]\boxed{\tau_b = \frac{4 m_p}{3} \left(\frac{E_b}{\hbar c} \right)^2 \sqrt{\frac{r_{\odot}^7}{2 G m_{\odot}^3}}}[/tex]

[tex]\tau_b = 15.722 \; \text{s}[/tex]

Based upon this particle rate, and presuming this rate is constant, how much time would be required for a single quantum black hole to consume Terra?

[tex]\boxed{t_e = \frac{4}{3} \left(\frac{E_b}{\hbar c} \right)^2 \sqrt{\frac{r_e^7}{2 G m_e}}}[/tex]

[tex]t_e = 7.951 \cdot 10^{53} \; \text{s}[/tex] - 2.521*10^46 years

BH horizon radius as function of energy:
[tex]r_h(E_b) = \frac{\hbar c}{E_b}[/tex]

Theoretical upper limit:
[tex]\boxed{t_e = \frac{4m_p}{3} \sqrt{\frac{(m_e c)^3 r_e^7}{2 \hbar^5}}}[/tex]

[tex]t_e = 6.874 \cdot 10^{131} \; \text{s}[/tex] - 2.180*10^124 years

[tex]\boxed{t_a = \frac{c^4}{4 \pi} \sqrt{\frac{r_e}{2 G^5 m_e^3}}}[/tex]

Time required to absorb 1 m^3 of Terra:
[tex]t_a = 6.844 \cdot 10^{16} \; \text{years}[/tex]

Note that if such an event were possible, the Universe would have generated trillions of such particles.

Reference:
classical stable micro-singularity absorption cross-section - Orion1 #75
classical stable micro-singularity absorption cross-section - Orion1 #83
classical stable micro-singularity absorption cross-section - Orion1 #90
classical stable micro-singularity absorption cross-section - Orion1 #104
Rascalking
#49
Aug26-08, 02:02 AM
P: 3
Hey everyone. Sorry if this topic has been played to death, but like many, I'm having pretty high anxiety about the start up of the LHC in a few weeks. Just got engaged, new job, life is really starting for me. I'm afraid it might be cut short cause of this thing. Theres so much speculation about what this machine can bring, and I'm actually seeing more doomsdayers on the internet then people with faith in the project. So, I decided to come to the most rational message board I could think of. A Physic board, since the whole machine is one giant physics experiment. I keep seeing article after article that offers a counterargument to the "its safe" theory. This one specifically caught my attention:

http://arxiv.org/PS_cache/arxiv/pdf/...808.1415v1.pdf

If this machine is "so safe" why are all these distinguished scientists fighting so hard against it? Some of these guys ARENT nutballs. So....is this really safe? Like I said, sorry if this has been discussed before but if I could get some reassurance from you guys, it'd be great cause I've definitely been losing lots of sleep over it.
Gear300
#50
Aug26-08, 02:30 AM
P: 1,133
don't worry...what happens will happen when it happens...life is only life...do not mourn over it...do not obsess over it
Vanadium 50
#51
Aug26-08, 05:23 AM
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Quote Quote by Rascalking View Post
If this machine is "so safe" why are all these distinguished scientists fighting so hard against it?
Which distinguished scientists?

Quote Quote by Rascalking View Post
Some of these guys ARENT nutballs.
Which ones? They all seem like nutballs to me. Particularly those who are advocating violence - see ZapperZ's blog for an interesting response.
arivero
#52
Aug26-08, 06:07 AM
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Quote Quote by Rascalking View Post
Hey everyone. Sorry if this topic has been played to death, but like many, I'm having pretty high anxiety about the start up of the LHC in a few weeks. Just got engaged, new job, life is really starting for me. I'm afraid it might be cut short cause of this thing.
As a joke it starts to wear. But still I like this one, with an hidden scent of irony about how the world works (not in the GUT/TOE sense, but in the sense of engaged + get a life + progress etc)
james77
#53
Aug27-08, 03:44 AM
P: 22
Quote Quote by Vanadium 50 View Post
Which distinguished scientists?



Which ones? They all seem like nutballs to me. Particularly those who are advocating violence - see ZapperZ's blog for an interesting response.
Which ones. Well see Giddings & Mangano for example and, Plaga as noted in his paper on the 10th August 2008 and again Martin Rees in numerous articles. These guys cannot be dismissed, arrogantly as "Nutjobs". To do so is not only ignorant and offensive but deeply stupid too, as any scientific theory evolves through a process of constant refinement between inherent possibilities, and some of these possibilities are initially identified as risks. Remember Einstein's infamous but highly understandable concerns before the first nuclear tests in July 1945?
Vanadium 50
#54
Aug27-08, 05:51 AM
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Quote Quote by james77 View Post
Which ones. Well see Giddings & Mangano for example
As examples of scientists "fighting hard against the LHC"? This is a total misrepresentation of their report.

As far as "arrogance", I marvel at the state of affairs where someone who criticizes a report that they don't understand isn't being arrogant, but where someone who points this out is.


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