that might be true for protons but not for heavy ions, and like you said most (all?) cr consists of protons and not heavy ions so how valid is that comparision really?

Repeating, with emphasis: "No, the observed upper limit is not 2 TeV. It is about 320,000,000 TeV. Again, this was probably a proton, but we're dealing with energy density. It doesn't particularly matter whether we're smashing protons, antiprotons, heavy ions or strawberries. If you don't believe me, which if fair enough, then ask a physicist."

It isn't just a comparison; it's a fact that energies millions of times greater than those even producible by LHC have been observed in nature. Laymen keep getting up hung up on this heavy-ion vs. proton thing, but it isn't really all that relevant. As Astrogeek mentioned, lead in particular is employed because it is necessary to reach the target energy in the machine. I'm a layman, too, of course, which is why I say you should contact a particle physicist if what I'm telling you isn't good enough. Most university faculty members, including some who have worked with LHC, have contact information on their web pages. How accommodating they'll be, I can't say. Maybe try posting at PhysForum — they've got some smart folks over there who are more than qualified to answer particle questions. You can also contact CERN directly.

the moon argument would also be invalid if cr exlusively consists of protons, wouldn't it?

It is still valid, because we're dealing with energy density.

Edit: Energy density at Wikipedia.

are the conclusions in lsag-report based on purely empirical evidence when it comes to stuff like vacuum metastability or have they done calculations on upper bounds?

For the details on the LSAG safety report's experiments and findings, you'll have to consult the references at the end of the paper. There are several, and the information is still good, which is why there isn't more detail in the report itself.

is this realy needless worries?

Yes.

If we can't quell your fears, why not try to contact a legitimate physicist. If the majority of the physicists who have studied this process say "Don't worry folks."

But, yeah. I'm no physicist. Not going to claim to be one. We're not going to be able to calm you down if we haven't been able to do so at this point. Again, I suggest you try to contact a physicist, as difficult as that may be.

And, no. I do not mean go on one of those physicist forums and post there. Unless you can identify a legitimate, neutral-stanced physicist and ask them.

But, honestly, don't worry about this. There's nothing you can do, and experts say it's not dangerous at all. And if it gets us all killed, oh well. Enjoy life.

the moon argument would also be invalid if cr exlusively consists of protons, wouldn't it?

are the conclusions in lsag-report based on purely empirical evidence when it comes to stuff like vacuum metastability or have they done calculations on upper bounds?

again, sorry for my ramble but this has realy messed up my entire life. im so afraid that something bad is going to happen when they start colliding heavy ions (which will reach as high energies as 574tev/nuclei). is this realy needless worries?

Actually the vacuum metastability scenario seems like a quite effective way to end all prospects of both present and future life, wouldn't you say?

Effective, sure, if it was known to exist and we had the capacity to create such an event, but I don't think we do, and apparently neither do any of the scientists involved with LHC. Notice that I asked you for a "compelling reason," not an "effective" method. I could tell you that switching on your bathroom light 3.2988 seconds after completing a Zuni rain dance will rip the fabric of space and kill everyone, and that sounds like a pretty damn sure way to end us and our planet, but just asserting the possibility isn't the same as offering a compelling reason to accept that possibility.

all that would be needed is a high enough particle collision with a com that rips through our current vacuum, but why trust lord martin rees and piet hut?

If you believe Martin Rees, Walter Wagner (who isn't even a physicist), Piet Hut et al., then why don't you believe the hundreds if not thousands of other scientists who have disagreed with them? Seriously, these are the guys (Wagner and Hut, at least) who raised the same complaints about RHIC. We're still here.

Even accepting Martin Rees' figures, which is apparently a stretch for some, his conclusion was on the order of 1 in 500,000,000, yes?

what do they know about quantum mechanics eh?

Not everything, which is one reason why peer review matters.

because it is, simple as that. they even admit to it indirectly by admiting that they haven't done any further research post-rhic, which sets an upper limit of 2tev(fe)/com

Did you even read my whole post?

and the upper limit they give is 2tev so how do they know 2.8tev/com will be safe?

No, the observed upper limit is not 2 TeV. It is about 320,000,000 TeV. Again, this was probably a proton, but we're dealing with energy density. It doesn't particularly matter whether we're smashing protons, antiprotons, heavy ions or strawberries. If you don't believe me, which if fair enough, then ask a physicist.

i can admit that gorelik isn't the most reliable or credible source, but i would dare say that martin rees is.

If you accept Martin Rees' figures and the claims of a handful of doomsayers over the conclusions of just about every other scientist who has weighed in on LHC, that's your prerogative. Also, what Martin Rees says bears no resemblance to anything that has been asserted by Ivan Gorelik.

no there haven't been.

Yes, there have been.

rhic is a pretty bad example since they collide au-au and cu-cu, and at far less energies (more like 200gev/com than 2.6tev

If you have read the LSAG safety report, then you should know why the lower-energy collision observations are important.

I think I'm with Moo on this one. It's pretty clear that you've already latched onto a conclusion and just want to fight about it now. Like I said above: If you've actually convinced yourself that a group of scientists would knowingly push forward with an experiment that could destroy the world or universe, then no amount of reassurance or counter-argumentation is likely to set your mind at ease anyway.

Pretty sure I gotta side with them on this one. Especially if Lord Martin Rees, as quoted, states the odds of doomsday are 1 in 500,000,000 - but don't quote me on that either. I don't know his odds nor do I want to know them 'cause they don't matter to me.

The thing is, when it comes down to your doomsday scenario, it's based off two theories.

1) The False Vacuum Theory being true.

2) Particle slamming being legitimately dangerous.

If both of these are not filled, then there's no risk. Considering "1" is highly disputed, I'm writing it off right away.

Considering "2" that more powerful events have happened and we still exist, I'm writing it off as well.

Ultimately, "WhyMe", what are you trying to obtain here? Your topic is not about 2012, but just another generic doomsday theory. And, okay, let's say that it was scheduled to launch in December 2012 (isn't it shutting down then?) and that both "1" and "2" are true… what the hell are you going to do about it?

You'd need to convince every scientist who's spent so much time on the LHC (and I guess as well the RHIC) that their studies and research are wrong, so I suggest you get to writing those letters. All you need to do convince them of is that two theories are correct. Shouldn't be terribly difficult?

Ultimately, I agree. The LHC isn't something that 'needs' to be operated. It doesn't have an aim of direct betterment of man kind, but it is being used for greater discovery of our origins, IIRC.

At the end of the day, however, I'm going to choose both "1" and "2" are wrong. Why? Because no amount of letter writing will convince CERN or anyone else that they're wrong and should sink millions of dollars on a project that's been going on for years.

Honestly dude, just weigh the odds. IIRC Lord Martin Rees has estimated the chances of doomsday as a result of the LHC are 1 in 500,000,000. I could be mis-quoted there and I honestly do not want to dig through LHC Conspiracy Theories while looking for legitimate information.

TL;DR - Stop worrying about the LHC. If a significant portion of the scientific community viewed it as a risk (As well as the RHIC), it would not have gone online. The only possible scenarios played out that would trigger doomsday are "1" and "2", both having to be true.

Conclusion: This is not 2012 related.

Can you come up with some compelling mechanism by which they have even the slightest chance of "killing us all?"

Actually the vacuum metastability scenario seems like a quite effective way to end all prospects of both present and future life, wouldn't you say? all that would be needed is a high enough particle collision with a com that rips through our current vacuum, but why trust lord martin rees and piet hut? what do they know about quantum mechanics eh?

Why do you say it is a lie?

because it is, simple as that. they even admit to it indirectly by admiting that they haven't done any further research post-rhic, which sets an upper limit of 2tev(fe)/com

This is why the LSAG doesn't go into detail about cosmic rays — they are covered in previous research, and the sort of specifics like energy density are already well known to particle physicists

and the upper limit they give is 2tev so how do they know 2.8tev/com will be safe?

i can admit that gorelik isn't the most reliable or credible source, but i would dare say that martin rees is.

There have been plenty of heavy ion observations, especially since RHIC went online, though I think that machine is relegated to energies at 2.6 TeV and below.

no there haven't been. rhic is a pretty bad example since they collide au-au and cu-cu, and at far less energies (more like 200gev/com than 2.6tev

(You did mean toenails, right JuJu?)

Indubitably.

By the way, here is the link to where Ivan Gorelick gets handed his toenails.

(You did mean toenails, right JuJu?)

I'm realy loosing all hope of getting some sleep thanx to this awful theory.

There are no theories about LHC doomsday, only claims which CERN scientists have more or less patiently addressed. The same people who spread fear and panic over RHIC are the ones now doing the same over LHC.

How can CERN be alowd to do this experiments when they could end up killing us all?

Can you come up with some compelling mechanism by which they have even the slightest chance of "killing us all?"

They just say that energies higher than that are observed all the time, and that is more or less an outright lie.

Why do you say it is a lie?

According to the Rhic-report heavy ion CR are extremely rare and has only been observed at energies below 2tev at com (for iron i think). So how can they claim that they have empirical evidence that these energies (up to 2.8tev this year) are safe when they havent observed collisions, especially not pb-pb, above 2tev?

Collisions involving every natural element have been detected in our planet's atmosphere. I've got a source for that claim somewhere on here, but I'm too lazy to find it right now. Mind you, these aren't all ion-ion collisions, and it was recently discovered that cosmic rays are composed of protons. While I have no doubt that this has doomsayers giggling and doomsayer-believers cowering behind closed doors, the "moon argument" is still nonetheless valid. If you've read the LSAG safety report, then you should know what this is. What is at issue is the energy density, not the specific particle or ion in question, and the energies involved are still well below those occurring routinely in our own atmosphere, let alone throughout the Solar System, galaxy and universe.

This is why the LSAG doesn't go into detail about cosmic rays — they are covered in previous research, and the sort of specifics like energy density are already well known to particle physicists. Still, I really wish CERN would release a study or a statement concerning this, because it's become almost as annoying as 2012 crap. However, to scientists, there's no compelling reason to be worried about these experiments.

In any event, we're talking about a very old universe that routinely produces amounts of energy that we puny humans have a hard time even fathoming. To think the measly energies we've harnessed in the LHC could spark a cataclysm of some sort, to the point of wiping out the universe itself, is just positively outrageous. If you've actually convinced yourself that a group of scientists would knowingly push forward with an experiment that could destroy the world or universe, then no amount of reassurance or counter-argumentation is likely to set your mind at easy anyway.

why does people like this Gorelik guy claim that there are no observations of high energy cr consisting of heavy ions like pb, and that it's only pure spevulation?

Ivan Gorelik is a bit of a fear-monger who has a less than favorable standing among real scientists. I don't even think he has an education in particle physics. He gets some portion of his lower body handed to him over at PhysForum, if you're interested.

There have been plenty of heavy ion observations, especially since RHIC went online, though I think that machine is relegated to energies at 2.6 TeV and below. Anyway, even if there have been no observations of Pb-Pb collisions at the energies in question, it is still anything but "speculation," as I've hopefully explained above. If not, well, my standard response to LHC inquiries has become, "Ask a physicist, cuz I ain't one."

and as i said before, the comparision with cr aren't realy all that valid anymore (since heavy ion cr havent been observed above 2tev) so how can they know its safe when we haven't observed heavy ion cr as energetic as those achieved in the ALICE-program? how can they know that we aren't going to trigger a phase transition when they start to collide pb208? no one has ever done that experiment so how can they now its safe???

You can't? Okay then, goodies.

Now, let's start with your real problem. You're taking the word of, at the very best an amateur in physics, random people posting on random forums and giving their take on how things work.

You're taking they're word over people who had many, many years of study and research in physics and whatever field the LHC covers. The people you're taking of have likely never even seen the LHC, let alone have researched it in up-close detail on how exactly it works.

Personally? I don't see a point in the LHC. I think it's a waste of time and money, but hey. Someone thought it was a good idea so it got funded. And, well honestly, so what if it ends up killing us all? Are you going to stop it by traveling to it's location and blowing it up? By all means then.

It is true, though, that there are much stronger forces constantly around us that haven't ripped us apart yet. I believe this is the basis for why the LHC is considered a Non-Threat.

But, at the end of the day, I'm going to take the world of the highly-trained scientists and such over the guys posting their theories, hoping to make a name for themselves, on some random forum.

Also I thought the LHC was suppose to kill us all the moment it was turned on. Are people dragging it out now? Geeze…

I have read all the safety reports (Review of speculative disasterscenario at RHIC and LSAG-reports 03/08) and they are less then reasuring to be honest. They just say that energies higher than that are observed all the time, and that is more or less an outright lie. According to the Rhic-report heavy ion CR are extremely rare and has only been observed at energies below 2tev at com (for iron i think). So how can they claim that they have empirical evidence that these energies (up to 2.8tev this year) are safe when they havent observed collisions, especially not pb-pb, above 2tev?

why does people like this Gorelik guy claim that there are no observations of high energy cr consisting of heavy ions like pb, and that it's only pure spevulation?

Please help me figure this things out, i'm realy realy scared of thiws