Exploring the Risks of the Large Hadron Collider

[humanino]

While discussing LHC one safety argument is, that mini black holes
would evaporate via Hawking radiation.

No. The safety argument is that BH should already be produced in the atmosphere from cosmic rays, but we are still here. This is different from "how to calculate what would happen if they don't evaporate".

 

[dmitrrr]

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]

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]

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]

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]

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]

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]

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]

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.com/2008/07/argonne-scientist-to-become-atlas.html
http://physicsandphysicists.blogspot.com/2008/07/argonne-scientist-to-become-atlas_21.html

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

Zz.

 

[Topher925]

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]

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]

Black Hole miscalculation?

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]

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:
$$\boxed{\tau_b = \frac{4 m_{Fe}}{3} \left(\frac{E_b}{\hbar c} \right)^2 \sqrt{\frac{r_e^7}{2 G m_e^3}}}$$

$$\tau_b = 12331.540 \; \text{s}$$ = 3.425 hrs.

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

$$\tau_b = 15.722 \; \text{s}$$

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?

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

$$t_e = 7.951 \cdot 10^{53} \; \text{s}$$ - 2.521*10^46 years

BH horizon radius as function of energy:
$$r_h(E_b) = \frac{\hbar c}{E_b}$$

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

$$t_e = 6.874 \cdot 10^{131} \; \text{s}$$ - 2.180*10^124 years

$$\boxed{t_a = \frac{c^4}{4 \pi} \sqrt{\frac{r_e}{2 G^5 m_e^3}}}$$

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

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

Reference:
https://www.physicsforums.com/showpost.php?p=1005179&postcount=75"
https://www.physicsforums.com/showpost.php?p=1007655&postcount=83"
https://www.physicsforums.com/showpost.php?p=1013784&postcount=90"
https://www.physicsforums.com/showpost.php?p=1044060&postcount=104"

 

[Rascalking]

New LHC article with theory on MBH's...

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/0808/0808.1415v1.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]

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]

If this machine is "so safe" why are all these distinguished scientists fighting so hard against it?

Which distinguished scientists?

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]

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]

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]

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.

 

[vanesch]

One shouldn't forget that the LHC is not such an exceptionally more powerful machine than are other colliders. Tevatron has ~ 2 TeV c.o.g. energy, LHC will have 14 TeV, just 7 times more. It is just because theorists have been idle for several decades that they came up with micro black holes at LHC.
The step from accelerators to colliders was a bigger step than from the Tevatron to the LHC.

 

[Cvan]

They speculated that they could ignite the atmosphere of the Earth ablaze when they dropped the first nuclear bomb.

They speculated Columbus would fall off the edge of the world on his trip.

And now they're speculating that there's a remote possibility of creating something that has never been directly observed, and would, in any case--basically evaporate in such a fashion that the only way to know it was ever there would be after years of testing the data. And people are worried about this.

What has the world become?

 

[humanino]

<mode=general discussion>

What has the world become?

Again : when did the world change ?
</mode>

 

[jms5631]

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.

Giddings and Mangano? Mangano was part of the group who studied the 2003 report and reaffirmed its safety. Then both went into even more depth in a second paper specifically exploring the question of the possibility of macroscopic, stable black holes, and here again validated the LHC as safe. I do not see how you can consider either of these scientists as people voicing their concerns about the safety of the LHC when they've specifically confirmed its safety. As for Rees, I don't know what numerous articles you're referring to...I've only heard him give the chances of anything unexpected happening at no more then 1 in 50,000,000(take note this is the upper limit of any supposed likihood, not necessarily the actual one). Even this seemingly remote possibility has been criticized as far too high by many physicists. As far as I can tell, out of the men you've listed, Plaga is the only one who legitimately supports this point of view.

 

[vanesch]

Remember Einstein's infamous but highly understandable concerns before the first nuclear tests in July 1945?

If you are referring to "igniting the atmosphere", then that's definitely not Einstein, but... Edward Teller ! And it was Hans Bethe who showed him wrong by several orders of magnitude. It's pretty ironic, because after that, Teller's obsession was... to make a hydrogen bomb!

 

[james77]

The Hungarian physicist Leo Szilard spoke to Einstein about the consequence of a uranium based chain reaction occurring after denotation. Quote 'The possibility of a chain reaction in uranium hadn't occurred to him, but as soon as I began to tell him about it he saw what the consequences might be.' A letter, signed by Einstein, was then sent to the American president, Franklin Roosevelt. This meeting occurred in a few months in advance of the first test.

On the subject of safe stable MBHs, yes indeed they may be safe (theoretically) to a certain point, but beyond the initial thresholds set, I think that it's difficult to make a prediction with regard to their ultimate stability and durability. Maybe they will vaporise as quickly as they were created, then again perhaps not. To be truthful we don’t really know, yet I imagine any catastrophic outcome is really a remote possibility as the experiments are being done in carefully controlled, graduated manner.

 

[ZapperZ]

On the subject of safe stable MBHs, yes indeed they may be safe (theoretically) to a certain point, but beyond the initial thresholds set, I think that it's difficult to make a prediction with regard to their ultimate stability and durability. Maybe they will vaporise as quickly as they were created, then again perhaps not. To be truthful we don’t really know, yet I imagine any catastrophic outcome is really a remote possibility as the experiments are being done in carefully controlled, graduated manner.

Still, what Vanadium and jms5631 are countering is your point that "all these distinguished scientists..." are fighting against the LHC, when no such thing is occurring. We have to be careful when we make statements like that, especially when this is a public forum and Google spiders pick those up quickly.

The "uncertainty" in knowing what will happen, if that is your argument, works both ways. If you criticize the LHC safety report that "we don't really know" about the consequences of the collision, then you also have to be equally critical of arguments that claim that it isn't safe, because such arguments will also, at the very least, make use of the same uncertain physics.

As far as I can tell, so far, you've only argued this simply based on a matter of tastes, which you must admit, isn't really conducive to any kind of rational, scientific discussion. There are many of us who have accepted the LHC report. There are also a few of us who went through the same brouhaha when RHIC was about to go online and remembered the same type of discussion. Unless the middle of Long Island has disappeared without the rest of the world knowing it (it was there a few months ago when I last checked), nothing came of it and the analysis that was done back then was obviously valid. So there IS a track record of success in this and it showed that we are not completely clueless. Rather, those who actually were predicting doom and gloom for RHIC were the one shown to be clueless (how come those people never trumpeted their failures now?). The LHC safety review is significantly more extensive than RHIC's. And these were not done by some no-name individuals either.

At some point, you need to consider if you are just going out on a fishing expedition, or if you truly have some indication from physics that this isn't safe. Doing the former is highly irresponsible, because you could shut down every single scientific advances that you are enjoying right now (I can tell you the horror outcome of superconducting technology that can fill pages, all via a fishing expedition).

Zz.

 

[vanesch]

The Hungarian physicist Leo Szilard spoke to Einstein about the consequence of a uranium based chain reaction occurring after denotation. Quote 'The possibility of a chain reaction in uranium hadn't occurred to him, but as soon as I began to tell him about it he saw what the consequences might be.' A letter, signed by Einstein, was then sent to the American president, Franklin Roosevelt. This meeting occurred in a few months in advance of the first test.

The meeting between Szilard and Einstein was years before the first test and that letter was actually a plea to develop a nuclear weapon, because Einstein's main worry was that Nazi-Germany might be developing one.
The issue of the ignition of the atmosphere had been discussed with Oppenheimer, Bethe, Szilard and others, and they came to the conclusion that it wasn't possible (based upon Bethe's corrections of Teller's wrong estimations), and all of them were after that convinced that no such thing could happen, although *rumors* circled (call them urban legends) that this wasn't the case.

It is true that Szilard wasn't happy with the way the politicians had taken control of the atomic bomb project (which he considered "his" invention), and he wanted to air his disagreement about that to Roosevelt, but it had nothing to do with igniting the atmosphere.

You can read the 4 letters that Einstein wrote right here:
http://hypertextbook.com/eworld/einstein.shtml

 

[jms5631]

On the subject of safe stable MBHs, yes indeed they may be safe (theoretically) to a certain point, but beyond the initial thresholds set, I think that it's difficult to make a prediction with regard to their ultimate stability and durability. Maybe they will vaporise as quickly as they were created, then again perhaps not. To be truthful we don’t really know, yet I imagine any catastrophic outcome is really a remote possibility as the experiments are being done in carefully controlled, graduated manner.

Have you read the safety analysis done by Giddings and Mangano? If not you really should head over to arivX and check it out. All the concerns you've voiced, I believe have been reviewed and answered in great depth in that paper...they've taken practically every contingent scanerio in which mini black holes would form, and ruled out any likelihood worth noting of their evolution into a stable, macroscopic one. In all likelihood, we're not even going to get unstable mini-black holes out of this machine, and the chances of anything unexpected happening are small enough to disregard.

 

[james77]

<At some point, you need to consider if you are just going out on a fishing expedition, or if you truly have some indication from physics that this isn't safe. Doing the former is highly irresponsible, because you could shut down every single scientific advances that you are enjoying right now (I can tell you the horror outcome of superconducting technology that can fill pages, all via a fishing expedition)>

I agree with the general premise of what you say above and, the point you make about the arguments that were circulated in advance of the RHIC are indeed both valid and timely. However, the results of this experiment do have the capacity, as indeed the first test of the atomic bomb on the 16/07/1945 in San Antonio had, to change totally not just Physicists, but humanities and indeed every living organisms’ relationship (and relationship is a key term here) positively or negatively to what constitutes our environs upon this planet.

O.K, say now comes the point where you tell me that this is a Philosophical/Ethnical consideration and that it shouldn’t be a real consideration that which pertains to the scientific experiments that will be conducted shortly. However, without digressing too much on this ethnical topic, all I can say (and this has been discussed as noted, excessively over the years) is that the possible knowledge gained from this experiment should be ideally weighted against the thought of risks and possible risks that may only become apparent during the experiments at different, unique stages of progression. There’s the possible scenario for example that at a certain stage during the experiments, well into the process that the possible risks may increase exponentially after a critical phase, because of the knowledge gained.

With regard to the Physics in question. I think the question of whether an Eddingtion limit can be established is of paramount importance. If evidence of such a limit becomes discernible during the initial stages of the experiment at the Thomson cross-section, assuming the radiation is photons, it will naturally exert a force where-






At this point there is the possibility of an exponential growth with t, of a MBH, assuming the above can balance the force of gravity pulling m, assuming m is the average atomic mass per electron), inwards.

Again, at this stage such a scenario may seem to be remote, but later on-going experimental data could perhaps prove otherwise.

I largely agree with a later poster’s view (that a least theoretically at this stage) that the likelihood of getting an array of unstable MBHs being produced by this machine is remote yet I don’t think that the risk can be totally dismissed just because it’s small, after all small is a very relative term in this context.

My equation seems to be unable to be applied on this page? It was the Thomson-coross scetion

 

[ZapperZ]

<At some point, you need to consider if you are just going out on a fishing expedition, or if you truly have some indication from physics that this isn't safe. Doing the former is highly irresponsible, because you could shut down every single scientific advances that you are enjoying right now (I can tell you the horror outcome of superconducting technology that can fill pages, all via a fishing expedition)>

I agree with the general premise of what you say above and, the point you make about the arguments that were circulated in advance of the RHIC are indeed both valid and timely. However, the results of this experiment do have the capacity, as indeed the first test of the atomic bomb on the 16/07/1945 in San Antonio had, to change totally not just Physicists, but humanities and indeed every living organisms’ relationship (and relationship is a key term here) positively or negatively to what constitutes our environs upon this planet.

What exactly are these environmental concerns? If a black hole forms that can swallow the earth, the LAST thing we would want to care about is such environmental concerns.

Again, these are rather undefined issues that you have brought up. In fact, it is exactly the fishing expedition that I had just presented. In other words, you don't quite know what exactly will happen, but you're just throwing out a bunch of stuff, hoping something would stick, or something would seem remotely valid.

With regard to the Physics in question. I think the question of whether an Eddingtion limit can be established is of paramount importance. If evidence of such a limit becomes discernible during the initial stages of the experiment at the Thomson cross-section, assuming the radiation is photons, it will naturally exert a force where-

At this point there is the possibility of an exponential growth with t, of a MBH, assuming the above can balance the force of gravity pulling m, assuming m is the average atomic mass per electron), inwards.

Again, at this stage such a scenario may seem to be remote, but later on-going experimental data could perhaps prove otherwise.

I largely agree with a later poster’s view (that a least theoretically at this stage) that the likelihood of getting an array of unstable MBHs being produced by this machine is remote yet I don’t think that the risk can be totally dismissed just because it’s small, after all small is a very relative term in this context.

Well, do you stop going out of your house because you're concern that you might get struck my lightning? Or do you avoid living in all or any parts of the world because there is a risk of earthquake, tornadoes, hurricanes, etc.. etc? If you don't, then maybe consider those risks versus the assessed risk of such things forming at the LHC and decide for yourself how rational and inconsistent you are in your concerns.

Zz.

 

[james77]

<Again, these are rather undefined issues that you have brought up. In fact, it is exactly the fishing expedition that I had just presented. In other words, you don't quite know what exactly will happen, but you're just throwing out a bunch of stuff, hoping something would stick, or something would seem remotely valid>

Yes, indeed the issues may well be undefined or even "fuzzy", but some of the findings that may occur from this experiment may well have to accommodated into categories that are not exactly neat and cosy in any conventional sense.

<In other words, you don't quite know what exactly will happen> Do you know what's going to happen, EXACTLY!

<Well, do you stop going out of your house because you're concern that you might get struck my lightning? Or do you avoid living in all or any parts of the world because there is a risk of earthquake, tornadoes, hurricanes, etc. etc? > Of course not, these are local, definable risks that have a certain probability of occurring over a certain period time, in a certain place, usually in a certain proscribed way or manner that allows a degree of prediction to occur. In other words, one can know what to expect within a finite space of time. You cannot compare these examples to the CERN project.

<If you don't, then maybe consider those risks versus the assessed risk of such things forming at the LHC and decide for yourself how rational and inconsistent you are in your concerns> I don't think my views have been either inconsistent or irrational. I have simply just noted that there is a very low risk scenario that there could be a negative result (s) based upon different possible outcomes that have been quite widely discussed amongst Scientists for some time now. I don't believe stating this should mean that one automatically becomes assigned to the lunatic fringe! How odd and irrational that would be!

 

[ZapperZ]

<Again, these are rather undefined issues that you have brought up. In fact, it is exactly the fishing expedition that I had just presented. In other words, you don't quite know what exactly will happen, but you're just throwing out a bunch of stuff, hoping something would stick, or something would seem remotely valid>

Yes, indeed the issues may well be undefined or even "fuzzy", but some of the findings that may occur from this experiment may well have to accommodated into categories that are not exactly neat and cosy in any conventional sense.

I have no idea what you just said here. My argument of things that are rather undefined referred to what you described earlier. It has nothing to do with the experimental results of what we get out of the LHC.

<In other words, you don't quite know what exactly will happen> Do you know what's going to happen, EXACTLY!

No, but that is referring to the experimental results themselves. There's certainly MORE known about what will likely NOT to occur. And if I were to ask you if you think you know more about what will occur versus those physicists who wrote the LHC safety report, who do you think will win that?

<Well, do you stop going out of your house because you're concern that you might get struck my lightning? Or do you avoid living in all or any parts of the world because there is a risk of earthquake, tornadoes, hurricanes, etc. etc? > Of course not, these are local, definable risks that have a certain probability of occurring over a certain period time, in a certain place, usually in a certain proscribed way or manner that allows a degree of prediction to occur. In other words, one can know what to expect within a finite space of time. You cannot compare these examples to the CERN project.

<If you don't, then maybe consider those risks versus the assessed risk of such things forming at the LHC and decide for yourself how rational and inconsistent you are in your concerns> I don't think my views have been either inconsistent or irrational. I have simply just noted that there is a very low risk scenario that there could be a negative result (s) based upon different possible outcomes that have been quite widely discussed amongst Scientists for some time now. I don't believe stating this should mean that one automatically becomes assigned to the lunatic fringe! How odd and irrational that would be!

The examples I gave was in response to you stating that "small" is a "relative" term. So I asked you to compare the various aspect of several things that had "small" risks. If you live your life by assuming that such small risks are insignificant to affect your day-to-day decisions, then you need to look at the risk assessment of the LHC. Unless you have some valid reason to say that such risk assessment is not valid and that it is actually significantly higher than the group of "small risk" items that I've listed, then this whole issue is moot.

Zz.

 

[jms5631]

Look, the advent of quantum mechanics led to a radical new era in science: the end of certainty. We can only look at things probalistically, and thus must utilize proper risk assessment in all our endeavors. Concerns about safety, especially with some of the highly hypothetical situations presented are justified; the onus is on the scientists to demonstrate that this machine is "safe." No risk can be lowered to exactly zero, but what has been proven is that the risk is so incredibly remote, that in practical terms it can be disregarded. The day to day situations that Zapper Z brought up, which are far-fetched scanerios you likely don't give a second thought to, are statistically several orders of magnitude more likely then anything happening at the LHC. So if you consider walking down the street safe, then the LHC should be no problem. I agree with you that if a risk of any substance of something happening that could alter the lifetime of the Earth in comparison with the life expectancy of the solar system could be demonstrated, then it must be take seriously. However, that is not the case, and the best scientists in the world have comprehensively certified this machine as safe. The lower energy limits in the LHC have already been probed in the Tevatron, and its capibilities are only a few orders of magnitude higher then the Tevatron, as Vanesch pointed out. There really is no cause for concern.

 

[james77]

<Look, the advent of quantum mechanics led to a radical new era in science: the end of certainty> This is of course true up to a point, yet the everyday Euclidean world of casual objects is still mostly determined by the Laws of classical Physics, Newton's Laws of motion for example, which allow one to make certain accurate, repeatable predictions about physical objects under various conditions in the world, still hold as good today as they did before the 20th century. Yes, it is certainly true that quantum mechanics has introduced a relative degree of uncertainty into our conceptual understanding and consequential mathematical modelling of the world at this microscopically tiny level. However, sometimes people make the mistake of describing quantum mechanics as a theory that seems to operate or be only applicable in a universe that gives the appearance of being totally apart from the classical, Euclidean everyday world of Newtonian Physics. While in essence quantum mechanics does indeed contain the uncertainty you mentioned, up until now it has being difficult to describe the effects of this theory in the classical everyday Newtonian world.

< We can only look at things probalistically> In the quantum world this is very true, I think some of the possibly huge beneficial side-effects of the CERN project may relate to our mathematical understanding with regard probability and how it can be modeled in the real world.

< No risk can be lowered to exactly zero, but what has been proven is that the risk is so incredibly remote, that in practical terms it can be disregarded> I do and have largely concurred with this belief, despite what others may of thought on my early posts.


<I agree with you that if a risk of any substance of something happening that could alter the lifetime of the Earth in comparison with the life expectancy of the solar system could be demonstrated, then it must be take seriously> I just think (as mentioned earlier) that any potential “real” risk or risks will only become apparent during the evolution of this process (if indeed they ever materialize)

< The lower energy limits in the LHC have already been probed in the Tevatron, and its capibilities are only a few orders of magnitude higher then the Tevatron> Yes, but I think these few orders of magnitude are critical.

Regards

 

[humanino]

Since serious papers have been posted, and do not seem to convince some people, I'll post an opinion, just for fun :
(I have not seen it posted earlier, at least not in this thread)
What Will the LHC Find? (Sean Carroll)

• [...]
• Black Holes: 0.1%. One of the intriguing aspect of brane-world models is that gravity can become strong well below the Planck scale — even at LHC energies. Which means that if you collide particles together in just the right way, you could make a black hole! Sadly, “just the right way” seems to be asking for a lot — it seems unlikely that black holes will be produced, even if gravity does become strong. (And if you do produce them, they will quickly evaporate away.) Fortunately, the relevant models make plenty of other predictions; the black-hole business was always an amusing sidelight, never the best way to test any particular theory.
• Stable Black Holes That Eat Up the Earth, Destroying All Living Organisms in the Process: 10^-25%. So you’re saying there’s a chance?
• [...]
• God: 10^-20%. More likely than stable black holes, but still a long shot.
• [...]