Exploring the Risks of the Large Hadron Collider

In summary, the popular books on physics suggest that when the LHC goes on this summer we might accidentally create a black hole and destroy the planet. But physicists know what they are doing and the LHC will not destroy the Earth. Otherwise claims are simple displays of scientific misunderstandings.
  • #106


james77 said:
Respect is the minimum that members of general public deserve.
And on the public part, realization of what fundamental research has brought to society down to one's daily life is the minimum level of gratitude, even if one does not care about pure knowledge.

I personally do not worry the slightest bit about getting money for my research. It has been difficult, it is difficult, it will be difficult. But in any case, "we must know, we will know".
 
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  • #107
mal4mac said:
Dr Adrian Kent, a seriously qualified quantum theorist of DAMPT at Cambridge
Qualified for quantum cryptography or for particle physics ? How many cross-sections did this theorist predict ?

mal4mac said:
It reports that CERNs top theorists are suggesting we shouldn't worry. I'd be much happier if Moscow and CalTech had produced such a comment. Aren't CERN theorists just slightly :-) interested parties? There's a one in many millions chance of Dr CERN-Theorist being exterminated if CERN goes online, but zero chance of them getting a Nobel if it doesn't! So the odds look great to them...
At some level, anybody qualified to give his opinion is interested in LHC. Even people working at the Tevatron for instance. Pick up your phone and call a couple of Russian or Californian physicists if you trust them more than Swiss ones. And come here report on what they told you.
 
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  • #108


humanino said:
Please realize that this is an important topic. By locking the thread, you jeopardize the credibility of the scientific community as long as the public community is significantly worried. It is very painful for the scientific community, but it is the only way we can say we "respect the public".



yes you are right. Even in China here many people are worried about LHC. In this thread after reading some thoughts I feel a little better. I regret not being admitted by Physics major...
 
  • #109
Pick up a phone? How 20th century...

Here's some more information on worried *physicists*, who even the establishment think are not crackpots:

Michelangelo L. Mangano, a respected particle physicist who helped discover the top quark in 1995, now spends most days trying to convince people that his new machine won’t destroy the world.

“If it were just crackpots, we could wave them away,” the physicist said in an interview at the European Organization for Nuclear Research, known by its French acronym, CERN. “But some are real physicists.”

http://articles.latimes.com/2008/apr/13/science/sci-collider13
 
  • #110
mal4mac said:
Pick up a phone? How 20th century...
That will be more efficient than an email, which most likely would be ignored.
Here's some more information on worried *physicists*, who even the establishment think are not crackpots:
That's not the way I understand it. The worried person who needs to be answered are "competent physicists" from the public point of view, not from Mangano's point of view. In the US, as soon as you have a PhD (in any discipline) you are entitled to give your opinion on any matter whatsoever. Take a University professor who spent his entire career building detectors. If this professor claims the CERN is unsafe, journals will report that University professors think so, possibly without making it clear this is an isolated opinion.

Mangano, who we agree is competent, spents his time making it clear CERN is safe, because less competent people considered competent by the public claim it might not be safe.
 
  • #111
humanino said:
Qualified for quantum cryptography or for particle physics?

Qualified enough to get published in a top journal called "Risk Analysis"...
 
  • #112
mal4mac said:
"What's an Acceptable Risk for Destroying the Earth?

It's funny, but there's an entirely adequate answer to that, as far as we consider that the only valuable thing on Earth are the human lives that are right now living on it, and that we don't delve into ethical and philosophical debates about "Gaia" or "future generations" and so on. After all, if Earth is destroyed, those future generations will never exist, and hence will never have to be considered.

So we have to find out what is the acceptable risk of killing 6 billion people. Given that car accidents alone already kill 1.2 million people per year, and that this is considered an acceptable risk, visibly if the risk of killing 6 billion people is acceptable on the same level, it should be of the same magnitude, which means that the probability of it occurring should be about 5000 times smaller (because 5000 times more lives) than the probability of killing 1.2 million people, which is once every year. So the acceptable risk of destroying Earth must be about 1/5000 per year.

Of course, something is not right in this reasoning, and that is that the acceptability of a certain risk is a function of the advantage we get from taking that risk. We accept 1.2 million dead per year because it allows us to travel around. It is not clear that the LHC gives us the same kind of global benefit. But I guess a probability of 1/5000 per year probability of destroying the Earth is in the acceptable ballpark, give or take a few orders of magnitude.
 
  • #113
mal4mac said:
Qualified enough to get published in a top journal called "Risk Analysis"...
That is certainly not a top journal in the particle physics community. Not any more important than Time magazine for instance. If it were published in Phys Rev (something) maybe I would take your argument.
 
  • #114
vanesch said:
... the only valuable thing on Earth are the human lives that are right now living on it... After all, if Earth is destroyed, those future generations will never exist, and hence will never have to be considered.

I disagree. Future generations are, surely, likely to produce new artistic masterpieces, new physics and so on. And surely even a potential for such advances is worth saving, and must be taken into account. And what about the past? If the Earth is destroyed then all past human culture will be destroyed, all life, and the evolutionary record. Surely all these things are valuable? Or are historians and evolutionists just wasting their time?

vanesch said:
Given that car accidents alone already kill 1.2 million people per year, and that this is considered an acceptable risk...

I don't think it's acceptable. One of the reasons I don't have a car...
 
  • #115
mal4mac said:
I disagree. Future generations are, surely, likely to produce new artistic masterpieces, new physics and so on. And surely even a potential for such advances is worth saving, and must be taken into account. And what about the past? If the Earth is destroyed then all past human culture will be destroyed, all life, and the evolutionary record. Surely all these things are valuable? Or are historians and evolutionists just wasting their time?
You don't understand the logical argument. Vanesch's logical argument is perfectly valid. I would even add to it : "unless we keep on doing fundamental research, we are certain to never be able to leave this planet, hence ultimately disappear".
I don't think it's acceptable. One of the reasons I don't have a car...
But then your opinion is clearly irrelevant, in the mathematical sense since it is completely negligible, or to put in another way, the set of people who think humans should give up cars can be given (in more than one manner) a null measure in the set of all humans.
 
  • #116
humanino said:
That is certainly not a top journal in the particle physics community. Not any more important than Time magazine for instance. If it were published in Phys Rev (something) maybe I would take your argument.

This is an outrageous dismissal of another speciality.

By the way, this issue is exploding in the UK at the moment. It was a lead item on news radio this morning ("Today"), and the satire shows are really panning physicists (Mock the Week on BBC2 yesterday and Armando Iannucci's Charm Offensive on Radio 4 while I'm writing this!). CERN need to get their PR machine working...
 
  • #117
mal4mac said:
This is an outrageous dismissal of another speciality.
Sorry but I also don't care that Nature does not publish so much of fundamental physics. The only reason they don't is because we can't provide with beautiful color pictures.

This is outraging you but unfortunately it's true. You, yourself, can easily publish a paper claiming that LHC is dangerous. Just pick up a local newspaper. Why should the physics community at large care ? The paper you referred us to has no quotation. Strange for such an important paper don't you think ?

mal4mac said:
By the way, this issue is exploding in the UK at the moment. It was a lead item on news radio this morning ("Today"), and the satire shows are really panning physicists (Mock the Week on BBC2 yesterday and Armando Iannucci's Charm Offensive on Radio 4 while I'm writing this!). CERN need to get their PR machine working...
Yet another way to see it, there is no such thing as bad publicity.

Finally, it does not matter to me that the UK is mocking physicists : I'm french :tongue2: More seriously, the attempt to sue CERN has been dismissed by Europe. What do you have to say about that ?
 
  • #118
mal4mac said:
I disagree. Future generations are, surely, likely to produce new artistic masterpieces, new physics and so on. And surely even a potential for such advances is worth saving, and must be taken into account. And what about the past? If the Earth is destroyed then all past human culture will be destroyed, all life, and the evolutionary record. Surely all these things are valuable? Or are historians and evolutionists just wasting their time?



I don't think it's acceptable. One of the reasons I don't have a car...

Ok, I think I'll start a thread in the philosophy forum on this thing:
https://www.physicsforums.com/showthread.php?p=1860805#post1860805
 
  • #119
mal4mac said:
By the way, this issue is exploding in the UK at the moment. It was a lead item on news radio this morning ("Today"), and the satire shows are really panning physicists (Mock the Week on BBC2 yesterday and Armando Iannucci's Charm Offensive on Radio 4 while I'm writing this!). CERN need to get their PR machine working...

Here's what everyone's favourite British newspaper has to say: http://www.dailymail.co.uk/sciencetech/article-1052354/Are-going-die-Wednesday.html

I wonder how difficult it is to get into scientific journalism? It's something I've always pondered doing.. it really hurts to see such terrible articles being written (and this is not the worst by a long way-- I was speaking to my mum the other day and she was asking me what I thought about CERN "creating new universes".)
 
  • #120
cristo said:
I wonder how difficult it is to get into scientific journalism? It's something I've always pondered doing.. it really hurts to see such terrible articles being written
I think, unfortunately, you would be a very unpopular journalist. Which means, they know very well what they are writing I'm afraid. I wish I'm wrong.
 
  • #121
humanino said:
I think, unfortunately, you would be a very unpopular journalist. Which means, they know very well what they are writing I'm afraid. I wish I'm wrong.
That may be true, but then again I've seen some very good scientific columns/sections of certain (free) papers. I'm fully of the opinion that it can be done: that is, one can sell a subject to the general public without having to sensationalise it: especially something like the LHC.
 
  • #122
cristo said:
That may be true, but then again I've seen some very good scientific columns/sections of certain (free) papers. I'm fully of the opinion that it can be done: that is, one can sell a subject to the general public without having to sensationalise it: especially something like the LHC.
You are completely right. I'm just being negative :smile:
 
  • #123
cristo said:
That may be true, but then again I've seen some very good scientific columns/sections of certain (free) papers. I'm fully of the opinion that it can be done: that is, one can sell a subject to the general public without having to sensationalise it: especially something like the LHC.

Humanino is right: you'd be a bad writer :tongue:
 
  • #124
extreme historical re-enactment …

mal4mac said:
By the way, this issue is exploding in the UK at the moment. It was a lead item on news radio this morning ("Today"), and the satire shows are really panning physicists (Mock the Week on BBC2 yesterday and Armando Iannucci's Charm Offensive on Radio 4 while I'm writing this!). CERN need to get their PR machine working...

From BBC radio (Armando Iannucci's Charm Offensive) this afternoon: :smile:
The Large Hadron Collider is recreating the first moments of our universe, which is actually the most extreme historical re-enactment society you can ever get.
 
  • #125
well um our science teacher told us that in LHC if the atoms didn't collide at the speed of light on wednesday, that the world will become a huge black hole and suck us in!!!!!!!!!!!!!!!


Is this true!?This scared the whole class!

Help me by analysing this ~~!Thanks ~!~
 
  • #126
In short, no. I don't understand the rationale, particles won't be accelerated to the speed of the light under any circumstance in the LHC. Very close to it, but not quite there. Particles collide at far less than the speed of light in other colliders, and everyday in the upper atmosphere and we are still here. I don't know if your teacher was joking or if you just misunderstood him, but I can't tell you where he's coming from here.
 
  • #127
jms5631 said:
In short, no. I don't understand the rationale, particles won't be accelerated to the speed of the light under any circumstance in the LHC. Very close to it, but not quite there. Particles collide at far less than the speed of light in other colliders, and everyday in the upper atmosphere and we are still here. I don't know if your teacher was joking or if you just misunderstood him, but I can't tell you where he's coming from here.


Thanks! I am just a freshman(not physics major).The controversies on LHC have disturbed me a lot for so many days. I feel much better now.
 
  • #128
I understand, there are a ton of misrepresentations and media sensationalism out there. As someone without a significant science background, you are in a position of vulnerability to these misunderstandings and manipulation of the fundamentals, like the majority of the people out there. Just know that the aim of science is to uncover objective truths about the world to deepen our understanding; surely that would diffcult to accomplish if it were oblitierated. Scientists have a very solid thoeretical and observational grasp of the physics involved in high energy collisions such as these. We see higher in the atmosphere on a regular basis. Even if you can't understand the substance of these papers, read the conclusions of the reports to put your mind at ease.

http://arxiv.org/PS_cache/arxiv/pdf/0808/0808.4087v1.pdf
http://arxiv.org/PS_cache/arxiv/pdf/0807/0807.3349v1.pdf
http://arxiv.org/ftp/arxiv/papers/0806/0806.3414.pdf
 
  • #129
mal4mac said:
Dr Adrian Kent, a seriously qualified quantum theorist of DAMPT at Cambridge, has worries:

"What's an Acceptable Risk for Destroying the Earth?

From time to time, people have raised the worry that a particular physics experiment just might destroy the Earth. The first time this was seriously considered seems to have been before the first A-bomb and H-bomb tests. More recently, the possibility was raised that, if unknown physics included some particularly unfortunate features, the RHIC experiments at Brookhaven, or the forthcoming ALICE collider experiments at CERN, could have disastrous consequences. When physicists address these worries at all, they've tended to argue that (a) something would have to be very wrong with our understanding of physics for the risk to be present at all, (b) even if it is, we can show on empirical grounds that any risk must be so small that the possibility just isn't worth worrying about. Which rather begs the question, of course: how small *is* an acceptable risk? On this point, the various analyses seem to have been extraordinarily cavalier. At various times physicists have argued for going ahead with experiments without further ado on the basis of risk bounds ranging from 1 in 5000 (!) (the first Brookhaven analysis of the RHIC experiments) through 1 in 300,000 (Compton's estimate of the probability of igniting the Earth's atmosphere in the first A-bomb test) to 1 in 50,000,000 (the CERN analysis of the RHIC experiments). It seems to me that a little thought suggests all these risk bounds are far, far too large for comfort."

From page two of "A critical look at risk assessments for global catastrophes" by Adrian Kent http://arxiv.org/PS_cache/hep-ph/pdf/0009/0009204v6.pdf:
II. HISTORICAL EXAMPLES
The first catastrophe mechanism seriously considered seems to have been the possibility, raised in the 1940s at Los Alamos before the first atomic bomb tests, that fission or fusion bombs might ignite the atmosphere or oceans in an unstoppable chain reaction. Investigation led to an analysis by Konopinski et al. [3] which fairly definitively refuted the possibility. Compton was later reported, in a published interview [4] with Pearl Buck, as saying that he had decided not to proceed with the bomb tests if it were proved that the chances of global catastrophe were greater than three in a million, but that in the event calculation proved the figures slightly less.
kressworks.com said:
A black hole ate my planet

...

Yet in November 1975, The Bulletin of the Atomic Scientists claimed that Arthur Compton, a leading member of the Manhattan Project, had said that there really was a risk of igniting the atmosphere. It turned out to be a case of Chinese whispers: Compton had mentioned the calculation during an interview with the American writer Pearl Buck, who had got the wrong end of the stick.
http://www.kressworks.com/Science/A_black_hole_ate_my_planet.htm [Broken]

Ahem. But of course, this is according to Kressworks (NewScientist). For what that's worth, I dunno.
 
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  • #130
OAQfirst said:
From page two of "A critical look at risk assessments for global catastrophes" by Adrian Kent http://arxiv.org/PS_cache/hep-ph/pdf/0009/0009204v6.pdf:

... At various times physicists have argued for going ahead with experiments without further ado on the basis of risk bounds ranging from 1 in 5000 (!) (the first Brookhaven analysis of the RHIC experiments) through 1 in 300,000 (Compton's estimate of the probability of igniting the Earth's atmosphere in the first A-bomb test) to 1 in 50,000,000 (the CERN analysis of the RHIC experiments). It seems to me that a little thought suggests all these risk bounds are far, far too large for comfort." ...

I'm a genius ! :biggrin:
 
  • #131
Here are two questions, thanks


Question.1.
I've read about the introduction about LHC and I know that the temperature produced in LHC would be 10,000 times higher than the center of the sun.
As the temperature is so high, what materials are used in LHC to prevent from being burned into ashes...?
Is there any possibility that such a scaring temperature causes a disaster?

Question.2.
If the LHC produces millions of black holes, would these mini black holes combine to a larger one which does not evaporate and has the ability to suck things in??


What's wrong with my thoughts above?? Please point it out to me ..Thanks!
 
  • #132
no sucky-power …

chinatruth said:
If the LHC produces millions of black holes, would these mini black holes combine to a larger one which does not evaporate and has the ability to suck things in??

Hi chinatruth! :smile:

A black hole has no sucky-power …

a black hole has exactly the same gravitational attraction as any star of the same mass.

It doesn't vacuum-up the things around it …

it's like one of those sea-creatures that just sits there open-mouthed and hopes other things swim into it. :smile:

Anything that goes past a black hole, however close, carries on past it, just like a comet "grazing" the sun.

Black holes in space only get larger because of collisions between other bodies, accidentally sending one of them in just the right direction.

And anything that accidentally falls into a black hole would have crashed into a star of the same mass in the same position long before.

If the sun or the moon were replaced by a black hole of the same mass, we wouldn't notice any difference (well, except for it being darker :wink:).

An uncharged mini-black hole would find it very difficult to hit anything!

Even a charged mini-black hole would probably just go into "orbit" round an ordinary particle (like an electron "orbiting" a nucleus) … and if it did manage to swallow anything of the opposite charge, it would become uncharged.
 
  • #133


tiny-tim said:
Hi chinatruth! :smile:

A black hole has no sucky-power …

a black hole has exactly the same gravitational attraction as any star of the same mass.

It doesn't vacuum-up the things around it …

it's like one of those sea-creatures that just sits there open-mouthed and hopes other things swim into it. :smile:

Anything that goes past a black hole, however close, carries on past it, just like a comet "grazing" the sun.

Black holes in space only get larger because of collisions between other bodies, accidentally sending one of them in just the right direction.

And anything that accidentally falls into a black hole would have crashed into a star of the same mass in the same position long before.

If the sun or the moon were replaced by a black hole of the same mass, we wouldn't notice any difference (well, except for it being darker :wink:).

An uncharged mini-black hole would find it very difficult to hit anything!

Even a charged mini-black hole would probably just go into "orbit" round an ordinary particle (like an electron "orbiting" a nucleus) … and if it did manage to swallow anything of the opposite charge, it would become uncharged.



Thank you very much for giving me such a specific answer!
What about the first question?? About the temperature??
 
  • #134
There is a difference between heat and temperature. You can stick your hand in an oven at 200C for a few seconds with no ill effect. If you tried that in a pot of boiling water at 100C, you would be very badly burned.
 
  • #135
mal4mac said:
At various times physicists have argued for going ahead with experiments without further ado on the basis of risk bounds ranging from 1 in 5000 (!) (the first Brookhaven analysis of the RHIC experiments)...

Kent is being more than a little disingenuous here. The 5000 number is actually 10000, it was in an other-than-final version of the paper, and most seriously, it is not what he claims it is. It's an intermediate step, and Busza et al. use this to explain why they prefer to use the astrophysical limits of Dar et al. instead of the astrophysical limits set by the moon surviving five billion years.

Personally, I think the standard Kent sets for risk ([tex]10^{-22}[/tex]) is absurd. Consider the risk that if we open a bottle, an angry genie will emerge from it and wipe out all life on earth. Since we've made maybe a trillion bottles to date, and this hasn't happened yet, we only know that the risk is less than around ([tex]10^{-12}[/tex]), a full ten billion times larger than Kent would permit. According to his argument, we should ban bottles.

mal4mac said:
It reports that CERNs top theorists are suggesting we shouldn't worry. I'd be much happier if Moscow and CalTech had produced such a comment. Aren't CERN theorists just slightly :-) interested parties? There's a one in many millions chance of Dr CERN-Theorist being exterminated if CERN goes online, but zero chance of them getting a Nobel if it doesn't! So the odds look great to them...

Once you've decided that physicists are murderous liars, willing to slaughter everyone on the planet (including their friends and families) in pursuit of a Nobel prize, there's really nothing left to say. Just out of curiosity, do you have any evidence for your claim?
 
  • #136
Then what are the differences between cosmic rays and the experiment in LHC??

CERN compared cosmic rays with LHC and got the conclusion that LHC would not produce any black holes because our Earth or other planets have been being bombarded by cosmic rays for billions of years but we are still safe.

From this logic, I can also get a prediction that we cannot find any "Higgs boson" because we didnot find that in any cosmic rays observed.(absolutely this is wrong)
I mean, the comparison between LHC and cosmic rays cannot hold water with me,


I want to know what's wrong with my thought.
 
  • #137
chinatruth said:
From this logic, I can also get a prediction that we cannot find any "Higgs boson" because we didnot find that in any cosmic rays observed.(absolutely this is wrong)

Cosmic rays are high energy particles from outer space that approach the earth, enter the atmosphere and scatter off particles in the atmosphere, resulting in showers of particles that fall to earth. The LHC is a setup in which two beams of protons are made to collide, and all the products are analysed such that all the energy of the system is conserved, and thus we can tell which particles are present. Such a thing is incredibly difficult to observe and tell what has happened, even when you've got a multi million pounds detector surrounding the event and calculating the energy given off by every single subatomic particle produced. It is impossible to perform such a calculation for cosmic rays.

The point is, though, that were black holes going to be produced at the energies of the LHC, then they would have been produced by cosmic rays. However, we're still here!
 
  • #138
be a detective …

Hi chinatruth! :smile:
chinatruth said:
What about the first question?? About the temperature??

I dunno! :redface:
chinatruth said:
Then what are the differences between cosmic rays and the experiment in LHC??

CERN compared cosmic rays with LHC and got the conclusion that LHC would not produce any black holes because our Earth or other planets have been being bombarded by cosmic rays for billions of years but we are still safe.

From this logic, I can also get a prediction that we cannot find any "Higgs boson" because we didnot find that in any cosmic rays observed.(absolutely this is wrong)

As cristo says, if the LHC produces Higgs bosons, then the cosmic rays will already have been producing them … but with no way for us to detect them.

Making particles go fast is easy :smile:. Detecting particles is difficult :cry: .

Remember, most of the expertise and expense in the LHC was not in building the accelerators, but in building the detectors! :wink:
 
  • #139
chinatruth said:
Question.1.
I've read about the introduction about LHC and I know that the temperature produced in LHC would be 10,000 times higher than the center of the sun.
As the temperature is so high, what materials are used in LHC to prevent from being burned into ashes...?
Is there any possibility that such a scaring temperature causes a disaster?
That temperature is produced in the void, at the centre of the "pipe", far from the container, and in a very small region of space, and for a very tiny fraction of second. Imagine a normal lamp: the tungsten filament reach more than 3000 °C, but the glass bulb doesn't melt.
 
  • #140
chinatruth said:
well um our science teacher told us that in LHC if the atoms didn't collide at the speed of light on wednesday, that the world will become a huge black hole and suck us in!!!!!!!!!!!!!!! Is this true!?This scared the whole class!

Help me by analysing this ~~!Thanks ~!~

On another note CERN is getting flooded with phone calls from panicky people either pleading to shut the machine down or giving them death threats.
 
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