Could the Large Hadron Collider Create a Black Hole That Threatens Earth?

[vanesch]

It occurs to me that a submicroscopic black hole passing through an atom would either swallow nothing at all, or the nucleus as a whole, or one of the electrons. It would thereby acquire a charge, which would quickly be neutralised by its attracting the rest of the mutilated atom. But its trail through the human body might be surrounded by several secondary ionisation events. Thousands of these trails might pass through an inhabitant of Geneva on any given day.

Guess what ? That's already happening: thousands of ionisation trails are crossing your body EVERY SECOND. It's natural radioactivity...

 

[Orion1]

pseudo-scientific...


Administrators, this thread is pseudo-scientific fiction ad nauseam and has devolved into off topic ad hominem, please lock this thread and move it to skepticism and debunking.

Thanks.
[/Color]

 

[humanino]

Administrators, this thread is pseudo-scientific fiction ad nauseam and has devolved into off topic ad hominem, please lock this thread and move it to skepticism and debunking.[/Color]

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".

 

[james77]

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".

Well, it's not just a case of the so-called Scientific Communities' respect for the general public. The CERN project must show a considerable degree of gratitude and respect to both the policy makers and the public across the EU who have given sizable sums (over the years) of money to this "affair", which is now being monitored extremely closely at such levels. If this project either goes wrong and doesn't deliver any significant or useful results, than there will be very little state or central support given to this type of scientific research in the future.

<It is very painful for the scientific community, but it is the only way we can say we "respect the public> It won't be as painful as getting your funding cut in the future.

Respect is the minimum that members of general public deserve.

 

[mal4mac]

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."

http://www.damtp.cam.ac.uk/user/apak/research.html

http://arxiv.org/abs/hep-ph/0009204 Risk Anal. 24 (2004) 157-168

Also check out:

http://news.bbc.co.uk/1/hi/sci/tech/7468966.stm

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...

 

[humanino]

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".

 

[humanino]

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 ?

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.

 

[chinatruth]

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...

 

[mal4mac]

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

 

[humanino]

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.

 

[mal4mac]

Qualified for quantum cryptography or for particle physics?

Qualified enough to get published in a top journal called "Risk Analysis"...

 

[vanesch]

"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.

 

[humanino]

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.

 

[mal4mac]

... 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?

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...

 

[humanino]

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.

 

[mal4mac]

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...

 

[humanino]

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 ?

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 More seriously, the attempt to sue CERN has been dismissed by Europe. What do you have to say about that ?

 

[vanesch]

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

 

[cristo]

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".)

 

[humanino]

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.

 

[cristo]

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.

 

[humanino]

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

 

[vanesch]

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

 

[tiny-tim]

extreme historical re-enactment …

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:

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.

 

[chinatruth]

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 ~!~

 

[jms5631]

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.

 

[chinatruth]

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.

 

[jms5631]

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

 

[OAQfirst]

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.

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

Ahem. But of course, this is according to Kressworks (NewScientist). For what that's worth, I dunno.

 

[vanesch]

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 !

 

[chinatruth]

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!

 

[tiny-tim]

no sucky-power …

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!

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.

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 ).

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.

 

[chinatruth]

Hi chinatruth!

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.

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 ).

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??

 

[Vanadium 50]

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.

 

[Vanadium 50]

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 (10^{-22}) 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 (10^{-12}), a full ten billion times larger than Kent would permit. According to his argument, we should ban bottles.

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?

 

[chinatruth]

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.

 

[cristo]

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!

 

[tiny-tim]

be a detective …

Hi chinatruth!

What about the first question?? About the temperature??

I dunno!

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 . Detecting particles is difficult .

Remember, most of the expertise and expense in the LHC was not in building the accelerators, but in building the detectors! ​

 

[lightarrow]

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.

 

[aquitaine]

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.

 

[vanesch]

Personally, I think the standard Kent sets for risk (10^{-22}) 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 (10^{-12}), a full ten billion times larger than Kent would permit. According to his argument, we should ban bottles.

I think this is an important point to make indeed. There are two kinds of risks associated with "doing new things". One risk is the objective probability that it will go wrong and do something evil, like eat up the earth. If the objective probability of such an event is stated to be p (say, 1 in 1 000 000 for instance) that means that if we were to repeat this experiment on, say, 100 million earth-like planets, that 100 of them on average would be eaten up/blown up whatever it was, and that 99 999 900 of them would be ok.

The other risk is the subjective risk (Bayesian "belief" risk) of weird things happening. This is not a probability in the frequentist sense, but a belief or not in the existence of a specific phenomenon, like evil genies popping out of bottles. Although certain theorists might feel insulted, posing the hypothesis of making tiny black holes at LHC energies which would not undergo Hawking radiation are, to me, not very far from genies popping out of a bottle. What "risk" is associated with such hypothetical phenomena ? If the phenomenon doesn't exist - that means, if it was just a quirk in the mind of a theorist or a story teller - then you can repeat the experiment on a gazillion earth-like planets, it will NEVER happen. If on the other hand, the phenomenon exists, it can occur at ANY rate, even "for sure". What do we do then ? It cannot be excluded that totally unexpected and weird things happen, and if we really do something totally new for the very first time in the universe, it is totally impossible to know. We might offend a deity which collapses the entire universe just by uttering a new phrase, we might get a genie out of a bottle, we might invoke the "coming of the great white handkerchief", or we might turn the Earth in a black hole.
Happily, most things (except for uttering phrases) we can do happen already somewhere in the universe, so by analyzing these things, we can sometimes obtain upper limits for the probability of the phenomenon happening under the hypothesis that the phenomenon is possible in the first place. But note that these estimates are not estimates of the probability that this will happen: they are conservative upper bounds.

Of course, from a decision PoV, Bayesian "ignorance" probability is probably to be treated on the same level as "genuine frequentist probability".
The danger of fixing too low probability levels for weird things to happen, is that we will for ever be stiffled in attempting new things - even at first totally inoffensive things, like writing phrases (which might invoke magical powers).

 

[chinatruth]

I think this is an important point to make indeed. There are two kinds of risks associated with "doing new things". One risk is the objective probability that it will go wrong and do something evil, like eat up the earth. If the objective probability of such an event is stated to be p (say, 1 in 1 000 000 for instance) that means that if we were to repeat this experiment on, say, 100 million earth-like planets, that 100 of them on average would be eaten up/blown up whatever it was, and that 99 999 900 of them would be ok.

The other risk is the subjective risk (Bayesian "belief" risk) of weird things happening. This is not a probability in the frequentist sense, but a belief or not in the existence of a specific phenomenon, like evil genies popping out of bottles. Although certain theorists might feel insulted, posing the hypothesis of making tiny black holes at LHC energies which would not undergo Hawking radiation are, to me, not very far from genies popping out of a bottle. What "risk" is associated with such hypothetical phenomena ? If the phenomenon doesn't exist - that means, if it was just a quirk in the mind of a theorist or a story teller - then you can repeat the experiment on a gazillion earth-like planets, it will NEVER happen. If on the other hand, the phenomenon exists, it can occur at ANY rate, even "for sure". What do we do then ? It cannot be excluded that totally unexpected and weird things happen, and if we really do something totally new for the very first time in the universe, it is totally impossible to know. We might offend a deity which collapses the entire universe just by uttering a new phrase, we might get a genie out of a bottle, we might invoke the "coming of the great white handkerchief", or we might turn the Earth in a black hole.
Happily, most things (except for uttering phrases) we can do happen already somewhere in the universe, so by analyzing these things, we can sometimes obtain upper limits for the probability of the phenomenon happening under the hypothesis that the phenomenon is possible in the first place. But note that these estimates are not estimates of the probability that this will happen: they are conservative upper bounds.

Of course, from a decision PoV, Bayesian "ignorance" probability is probably to be treated on the same level as "genuine frequentist probability".
The danger of fixing too low probability levels for weird things to happen, is that we will for ever be stiffled in attempting new things - even at first totally inoffensive things, like writing phrases (which might invoke magical powers).

you mean, the LHC experiment is an objective risk?

 

[Vanadium 50]

Of course, from a decision PoV, Bayesian "ignorance" probability is probably to be treated on the same level as "genuine frequentist probability".
The danger of fixing too low probability levels for weird things to happen, is that we will for ever be stiffled in attempting new things - even at first totally inoffensive things, like writing phrases (which might invoke magical powers).

The problem with making decisions this way is how do you make an objective comparison about the risks of opening the bottle and releasing an angry genie versus not opening the bottle and risking the wrath of the god of bottle-opening? According to this line of reasoning, neither of the two mutually exclusive actions has acceptable risks.

 

[vanesch]

you mean, the LHC experiment is an objective risk?

No. It is rather a subjective risk: we will do "new" things, and an exotic phenomenon which might have an evil effect can hence, by ignorance, not be excluded (just as vanadium's genie from the bottle). If we were really doing something unique in the LHC, then there would be no way to tell whether or not this might actually happen, and anybody's guess would be as good as any other.

However, what is going to happen at the LHC is not unique in the universe. From that given, we can try to derive an upper limit to the eventual objective probability of some evil effect, under the hypothesis that it even exists. THESE are the numbers you find scattered around. They are *upper bounds* for an unknown objective probability, which might very well actually be 0 (said phenomenon doesn't exist).

Vanadium gave the perfect example: it is not unconceivable that there is a low objective probability that an evil genie that will destroy the Earth pops out of a bottle when we open it. But from the fact that we already opened 10^12 bottles, and that this didn't happen, we can deduce that IF ever such evil genies exist, the probability for them to pop out of a bottle cannot be larger than about 10^-12. That doesn't mean at all that we estimated the probability of evil genies to exist to be about equal to 10^-12 - honestly I don't believe they exist at all. But I have no scientific way to prove to you that this won't happen, and hence the best I can do is to say that opening a new bottle will represent a probability smaller than 10^-12 to destroy the earth. If you require (as Kent does) insanely low risk levels, well, then 10^-12 is not good enough, and hence from now on it is prohibited to open any bottle. Do you realize the burden such requirement for extremely low risk levels entails ?

Now, opening bottles is a very common activity, and that's what allowed us in the first place to give the upper bound of 10^-12. But imagine that we said the same for, say, landing on the moon. Imagine that somebody fears that we might wake up a monster hidden in the moon, which will eat the earth. As we haven't done many moon landings, this time we don't have a 10^12 trials at our disposal. Only a few tens or at most hundred (if you include robotic landings and such). So "landing on the moon could have a 1% chance of destroying the earth!". Nobody made the argument, so we didn't worry. In the 60ies, there weren't many moonlandings and then "landing on the moon could have a 30% chance of destroying the earth". We didn't know. We took a huge risk waking up the monster in the moon. Turns out there wasn't such a monster... or actually, we still don't know - there's still a 1% upper bound on the risk of waking up the monster if ever we do a new moon landing. Should we risk the Earth ?

The thing with the LHC is similar. Normally, the LHC won't make black holes. It is only in very contrived theoretical speculations that spacetime is warped in such a way that the low LHC energies could do so, and even in that case, if they respect the second law of thermodynamics, they should evaporate immediately. This kind of theorist's invention is IMO not very far from evil genies, as it is based on not much more than a whole load of speculation.
But we don't know for sure, as this is new. So one looks at the number of natural collisions at LHC energies that would have had the potential to do so and tries to estimate an upper bound of the probability that an evil thing could have happened (from the fact that it didn't). This gives us then an upper bound of having anything seriously evil in the LHC. If no collisions ever happened in nature at LHC energies, we would not be able to find such an upper bound. We would be left with an upper bound of "100% chance that we destroy the earth".

 

[vanesch]

The problem with making decisions this way is how do you make an objective comparison about the risks of opening the bottle and releasing an angry genie versus not opening the bottle and risking the wrath of the god of bottle-opening? According to this line of reasoning, neither of the two mutually exclusive actions has acceptable risks.

Damn! We're doomed either way !

This is unbearable. Let us make a quick end to it and flip that switch on the LHC

 

[james77]

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".

Please do not tell me that the WWW is what we all should be grateful to CERN about. This does not in my mind rank as a significant scientific development, this would of occurred anyway, regardless of CERN. Significant reserach funding should be given to those areas of reserach that have a clear and measureable effect upon humanity as a whole. I think funding in the Biological sciences for example can yield much more useful and pratical benefits to the majority of Humanity. In the area of Physics for example more meaningful money could be spent upon the development of using new devices and technologies that could harness the power of other bodies, apart from our Sun, in order that we as a species might have some shared future. I simply don't believe that in the future we will be able to justify both the time and money that has been poured in projects like CERN.

 

[cristo]

Please do not tell me that the WWW is what we all should be grateful to CERN about. This does not in my mind rank as a significant scientific development, this would of occurred anyway, regardless of CERN. Significant reserach funding should be given to those areas of reserach that have a clear and measureable effect upon humanity as a whole. I think funding in the Biological sciences for example can yield much more useful and pratical benefits to the majority of Humanity. In the area of Physics for example more meaningful money could be spent upon the development of using new devices and technologies that could harness the power of other bodies, apart from our Sun, in order that we as a species might have some shared future. I simply don't believe that in the future we will be able to justify both the time and money that has been poured in projects like CERN.

But how can you guess what use something will be in the future if we don't understand it at present? Relativity, say, had no "use" when Einstein discovered it back in the 1900's, but I doubt you'd be able to live without it today!

 

[humanino]

But how can you guess what use something will be in the future if we don't understand it at present? Relativity, say, had no "use" when Einstein discovered it back in the 1900's, but I doubt you'd be able to live without it today!

Same story about electromagnetism.

 

[humanino]

I think funding in the Biological sciences for example can yield much more useful and pratical benefits to the majority of Humanity. In the area of Physics for example more meaningful money could be spent upon the development of using new devices and technologies that could harness the power of other bodies, apart from our Sun, in order that we as a species might have some shared future. I simply don't believe that in the future we will be able to justify both the time and money that has been poured in projects like CERN.

How do you get biology if we had not do physics in the first place ? Don't you think understanding atomic structures and having microscopes powerful enough to unveil the ADN (for instance) had any use to biology ? Do you hope to understand cell microbiology and chemical mechanisms without any use of physical concepts ? Are you aware that more and more biology teams hire physicists ? This is just a non-discussion on our part, we can not list you all that has been made possible though fundamental physics, neither can we tell you what future will be.

If you restrict physics to applied physics, it is only due to your lack of perspective. Are you aware that we will need to leave this planet at some point, due to limited ressources, if humanity is to survive ?

All right, check that out if you want another example :
http://www.eu-egee.org/

 

[peter0302]

Kudos to Vanesch and others for discussing intelligently the real risks - or lack thereof - involved with the LHC, rather than dismissing people's concerns as "baloney" as others have. Just because we are not - this week - going to destroy the Earth does not mean that we might not one day. A little humility really needs to enter into this community, more than ever when we start to play god by recreating the Big Bang.