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Why the LHC Won't Destroy the World
An anonymous reader writes "Most people are aware of the recent articles contending that the Large Hadron Collider at CERN might destroy the world. While most scientists have no such concerns, a recent preprint released to arxiv systematically dismantles the notion. The gist of the argument is this: Everything that will be created at the LHC is already being created by cosmic rays. If a black hole created by the LHC is interactive enough to destroy the world within the lifetime of the sun, similar black holes are already being created by cosmic rays. Such black holes would be stopped by dense cosmic objects (neutron stars and white dwarfs). A black hole stopped in one of these objects would eventually absorb it. We see sufficiently old neutron stars in the sky, thus any black hole that could be created at the LHC, even if it is stable, would have no effect on the earth on any meaningful timescale."
First particle?
rewriting history since 2109
Don't they see that there used to be MORE neutron stars?
According the the Farnsworth Theorem, which has been accepted by the scientific community, the LHC is almost certain to destroy the world. There are consequences to creating a black hole, you know.
Dr Farnsworth suggests that you collect your most prized possessions and carry them down to the lowest basement you can find. This way you will at lest be among the last survivors on our doomed planet.
Even if they did manage to destroy the world, we'd all die so quickly there wouldn't be time to dish out any blame.
I can imagine the last words in the lab just before we all disappear into a singularity:
"Oops"
Summation 2
This article doesn't take into account accidental resonance cascades that open up portals to bizarre alien.
Wasn't the actual "danger" in question the creation of stable negative strangelets (which would gobble up regular matter through electrostatic attraction, not through gravity like a black hole) ?
But still, if there was such a thing, cosmic rays would have created one "naturally" by now.
Logic is a feeble reed, friend. "Logic" proved that airplanes can't fly and that H-bombs won't work and that stones don't fall out of the sky. Logic is a way of saying that anything which didn't happen yesterday won't happen tomorrow. R. A. Heinlein Glory Road
I wouldn't worry really. If it does destroy the world (which this is saying it won't, because if it could, it would have already happened naturally), then too bad. There isn't anything we can do, and such is life. C'est la vie.
Oh yeah, and I really have been there, there was an open day a couple of months back, the thing is less then about 15 cm in most places (then you have the various vacuum thingys, etc.). Which is rather big, actually, considering the size of the particles...
I wank in the shower.
"Science is the work of the devil!"
I believe the saying goes, don't let the facts get in the way of a good story. "Safe" doesn't sell National Geographic, let alone Wired.
We will just sent sg1 in to take care of the aliens and then we just blame it on the homer simpson type people working there.
Let me be quite clear that I don't think the LHC is likely to destroy the Earth.
However, the argument that what the LHC does is equivalent to collisions of cosmic rays with the atmosphere is bogus. The LHC's collisions between two particle streams with equal and opposite momentum could create things that are more or less at rest with respect to the Earth; a cosmic ray hitting the atmosphere carries momentum that will cause any resultant particles to move away from us very quickly.
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
Interestingly Enrico Fermi did use the same argument while setting on the first nuclear reactor during the Manhattan project around 1940 (that some cosmic rays are anyway much more energetic and bombarding the Earth since ages). And later fission and fusion bomb makers did use the same argument while playing with increasingly powerful toys. Ditto particle physicists for each new and more powerful accelerator. Isn't it time that journalists and other dumb news makers understand?
"We have an unintended event horizon."
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
The world will not end when I flip this switch.
I shall prove this, by ...
What in the world could that be?!
*points over there*
*flips switch*
If you can read this, I forgot to post anonymously.
Now, now, if you follow standard insertion procedure, everything will be fine. ... Although I will admit that the possibility of a resonance cascade scenario is extremely unlikely.
Tie two birds together: although they have four wings, they cannot fly. (The blind man)
What does it mean that a black hole is "stopped"?
Swedish plasma phys. PhD student; MSc EE; knows maths, programming, electronics; finance interest; seeks opportunities
So when does it come online? Just in case something happens, I need the day off to do what I always wanted to do: Spend it with a beautiful woman in bed--who am I kidding? I'm posting on slashdot. I'll be playing GTA IV. :P
Well, there's spam egg sausage and spam, that's not got much spam in it.
So each being equally small in probability the two ways the LHC will get us is either by
1. Black Holes (like the article says)
or
2. Instantaneous conversion of all stuff on earth into exotic matter.
Personally #2 sounds more fun.
I never thought I'd see a resonance cascade, let alone create one.
You mad
"In theory", posting to Slashdot is safe.
"In theory" you can't accidentally summon the elder gods by not limiting your .signature to 120 characters.
"In theory" posting more than twice within a ten minute limit won't create an imbalance of left-handed and right-handed electrons within the local ethernet causing anything up to and including total protonic reversal. (I bet you'd be kicking yourself for not buying cables with signal directional markings which could have prevented this problem.)
So, yes, "in theory" the world is safe from being destroyed by you. Today.
And "in theory" that makes me feel better.
There's a big difference between people mouthing off in a "forum" and a carefully researched, scientific journal article. TFA is the latter (there are two actually) and weighs in at 88 pages! Further, they begin by rejecting the points in your post (which are assumptions that most reasonable people would begin with), to see what would happen, because the original claim by the folks in Hawaii did just that. Now hopefully some nutcase won't make us reject the assumption that dragons are not involved...
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
Yes, in theory. Just as the sun will rise tomorrow "in theory." And if I repeatedly shoot someone in the head, they will die, "in theory." And reality exists, "in theory."
Provability only exists in mathematics. For everything else, from decisions about what to buy at the supermarket, to designs of scientific experiments, we humans must use mental models that rely upon fundamental assumptions about how the universe operates (e.g. that past experiences allow us to make meaningful predictions). In other words, every action we take must be informed by some sort of "theory." The question then becomes "how robust is this model/theory?", "how much can I trust the predictions?", "what is the range of the possible outcomes?", "what are the consequences of errors in the assumptions/model/theory?", and so on.
If you have a specific problem with one of the assumptions, logic, modeling, mathematics, data acquisition, or analysis, then point it out in detail. But saying, "that's just a theory" is not useful. Everything we do is based on theories.
After all, the opposite is also a theory: Not turning on the LHC won't cause the destruction of the Earth... in theory.
See also the Review of the Safety of LHC Collisions which also appeared today, and is a more non-technical summary of the safety review.
1^2=1; (-1)^2=1; 1^2=(-1)^2; 1=-1; 1=0.
If you have a specific problem with one of the assumptions, logic, modeling, mathematics, data acquisition, or analysis, then point it out in detail. But saying, "that's just a theory" is not useful. Everything we do is based on theories.
Experiments are conducted based on our lack of confidence in those theories. Either this theory is trustworthy enough to make the whole experiment pointless, or it's not trustworthy and experiments are justified. You can't have it both ways, and anyone who attempts to defend the safety of an experiment with only the theories being tested as evidence is an idiot. There's uncertainty, and thus there's an experiment, and we don't really know what will happen. Period. Get over it already. One way or another, you're still going to die.
-1 Uncomfortable Truth
Slashdot doesn't need to hear all this, they're highly trained professionals. We've assured the administrator that *nothing will go wrong*.
Why is it that physicists on and in favor of this project (and those that are following this story) are even remotely surprised by the "Create a black hole, and destroy the world" rhetoric?
We've heard all the sensational "Black holes are the ultimate destructive force" commentary from Astronomers for decades seen all the cool Black hole animations, etceteras, ad nausium.
In my opinion, all the sensationalism surrounding the Black holes to start with was a ploy for funding. Now that same story line shows it's dark side, and people seemed surprised at the outcry and at overly dramatic fear of the LHC.
I'm not saying that sensationalizing science is a bad thing per se, just that people shouldn't be surprised when it bites them on the ass.
A positive attitude may not solve all your problems, but it will annoy enough people to make it worth the effort.
Way lower, here, can be as much as a factor of ten million.
Here's a nerdy but popular account of an extreme high energy cosmic ray detected at the Fly's Eye II. And that's just what we've detected in a few decades of running small detectors. What the planet has intercepted in the last few billion years must be even more staggering.
There are two opposing viewpoints on the matter.
On the one hand, we have particle physicists whose "theories" on the interaction of subatomic-scale matter is drawn from decades of research and experimentation.
On the other hand, we have people who know essentially no physics and seemingly assume that the people building the LHC must be as lost when it comes to science as they. They make the argument, "Well, we don't *really* know what's going to happen."
It's amazing that the latter are able to function, as crippled as they should be of the fear of uncertainty.
Or in even simpler terms: "We're doing this experiment because we want to find out what happens. We don't really know what will happen, but we assure you it will be perfectly safe."
I wouldn't think it would have too great an impact on tides and climates and such. Its gravity would only be as great as that of the sum of the mass it had absorbed, which by definition can't be more than the planet has now, so if it just sat there in the middle of the planet, it wouldn't change the gravity of the earth.
It's kind of like "Holy crap if the Sun collapsed into a black hole all the planets would be sucked in". If the Sun spontaneously collapsed and was a black hole, which theoretically can't happen because it doesn't have enough mass, the planets would orbit the black hole normally, just as they do the Sun now. The black hole would have the same mass as the sun, just be a lot smaller. We'd all die of course from things like "no heat", but the Earth would happily orbit its much smaller star.
Right? I'm not a physicist.
I like music
So, what is the worst case scenario, and, would I notice it?
Given that it's thought this can create weak stable black holes, couldn't they be used to generate power? I was tought in physics that when a big object 'enters' a black hole, it ejects a narrow stream of energy through the back of the black hole. If you couple this with Hawking radiation (or if what I'm talking about IS hawking radiation), couldn't you use black holes as a powersource? Something with the ability to convert 100% (eventually) of mass to energy must have huge power generation potential.
Please don't tell me what I'm thinking of is a ZPM, damn stargate Deus Ex machina devices...
"haven't accounted for 96% of the energy and mass of the universe in their current model."
They also haven't accounted for all possible group particle mergers and interactions in the LHC. Unlike nature, in a particle accelerator they have groups of high energy particles moving in close proximity. In nature, we have lone high energy particles. We don't know what we can create in group collision mergers of high energy particles and even though these are rare compared with single particle interactions, they can still occur. Even if a black hole like particle was briefly formed and then hit by another particle or two or twenty, then what?. The point is, we simply don't know whats possible, but its very likely to be a different situation than simply a lone particle able to break down. If a group collision merger occured in nature, it would most likely be very rarely occuring, but it could be enough to help account for some fraction of the mass of the universe. We simply don't know, but we do know that in a particle accelerator, its going to happen a lot more often than in nature and we don't know what kinds of reactions group high energy mergers could cause.
While its (mostly) safe to assume single high energy particles are not going to be a problem, as they happen relatively often in nature, we cannot say the same for multiple collsion mergers and all possible interactions of multiple particles, as we simply do not know for sure. The current various theories are not proof its safe and the fact we cannot account for so much energy and mass in the universe is a very good reason to suspect our theories are wrong.
Also the fact they are building the LHC is proof in itself that they build it to learn, so they don't currently know for sure. Also for all their planning, even that magnet failure showed their theories and multi-million dollar design plans about how the machine should function can still go wrong. Humans make mistakes. Thats fine, we all accept that, but making a mistake with the LHC could potentially be the most serious mistake in human history.
What concerns me is their intense desire to learn is going to bias their judgment. (I know my desire to learn has biased my judgment from time to time), but this is the most important experiment in human history, so its vital it doesn't go wrong in any way, or it could be the last experiment.
There are 10 kinds of people in the world... those who understand binary and those who don't.
- Energy of maximum LHC collision: 14 TeV
- Energy of "Oh My God Particle" cosmic ray that hit the sky over Utah in 1991: 300,000,000 TeV
Sources:All things told, I'd rather die by act of science than by act of war.
More Twoson than Cupertino
So, yes, "in theory" the world is safe from being destroyed by you. Today.
Is this a challenge?Well, exactly how small black holes _are_ we talking about? Because it seems to me that the whole scare is due to a few people's not really understanding physics.
Gravity is actually the weakest force at a particle level. But ok, let's imagine a really really small gravity well.
Arguably the interesting thing about one would be, basically, "up to what distance can it gobble things up." In other words, the the Schwarzschild radius.
I'll use simplified version, which is: 3km for something weighing as much as our Sun, and it varies linearly with mass from there. Literally. For Something the size of Earth it would be 9mm, btw, but they won't collide particles weighing the same as _Earth_ there. If they did, I'd worry about _recoil_ before I worry about black holes.
So how big a black hole will they create there? Say, about the weight of two neutrons? _Three_ neutrons? Heck, let's be generous and smash a whole five neutrons together. Each neutron weighs 1.67492729x10^27 kg. So 5 of them is very approximately 8x10^-27 kg. The Sun weighs 1.9891×10^30 kg, let's say 2x10^30 kg.
So we get roughly 3km times 4x10^-57 km, or 4x10^-54 metres. That's the ridiculously infinitesimal size, up to which it could gobble matter. By comparison a helium atom has a radius of 31 picometres, or approx 3x10^-11 metres. Our black hole is about 10 to the 43'th power smaller than that. Write a zero, a dot, 42 more zeroes and a 1. That's how much smaller that black hole is than a helium atom.
To be absorbed by it, another particle would have to come that close to it, overcoming all other forces. Which become pretty damn strong when you try to get that close.
In effect, the _only_ way for that "black hole" to gobble any other particle, is for that other particle to be shot directly at it with an even bigger particle accelerator. With some incredible (and thanks to that guy Heisenberg, also pretty much impossible) accuracy. Otherwise, it will be bounced around by the other atoms, without ever getting close enough to one to actually absorb one and get bigger and meaner.
If that's the big threat to Earth, well, I've seen scarier kittens than that ;)
A polar bear is a cartesian bear after a coordinate transform.
Let's put it this way:
We KNOW enough about the math, even with all the estimations and incomplete theories, to be able to say that, on the extreme outside chance the LHC does make a mini black hole, the mini black hole will evaporate/destroy itself in a time frame measured in tiny fractions of a second. It cannot destroy the Earth, let alone the solar system or the galaxy.
On the other hand, know nothing of the possibilities of interdimensional travel. Therefore, we are safer considering, and maybe preparing for, the possibility of Hellboy landing in the lab. And he ain't such a bad guy, really.
I hope this comment is well received... I could have moderated instead!
Persecutors will be violated!
Right? I'm not a physicist.
In short, you are correct. If you were to magically replace our Sun with a black hole of 1 solar mass, the gravitational pull would not change. There would be a whole lot of other stuff going on, but black holes don't magically increase the gravitational pull of a mass.
If I made a blackhole out of the amount of mass that the LHC is accelerating, and put it suspended in a sealed jar on my desk, I would only feel the gravitational pull of the mass that actually is the black hole. So, unless people are having difficulty with the gravitational pull of things on their desk, I wouldn't be too worried about it.
Out of modpoints but really liked a post? 1BDkF6TtmmeZ3yqXbz9yhdYVqRYnwFoXDj
My favorite crazy LHC theory is explained in glorious detail in this video. The guy seems reasonable to start, but he manages to pull in more kook-memes than you'd think possible. Delicious!
so the area around it where the gravity would significantly bend the universe would also be quite small, making our painful (but swift) deaths rather unspectacular
I'm sorry, but you're completely forgetting about at least one mitigating factor. There's simply no way the earth can be destroyed, one side effect of which would be my untimely demise. Why? Because I've still got a balance on my Capital One visa card, and they will do anything, including changing the very fabric of space and time, in order to not miss out on that interest money. So, we're safe for a while yet.
Don't disappoint your bird dog. Go to the range.
A2: The experiments planned for the LHC and any high energy collider are supposed to simulate the very early universe. The only comparable high energy events are a few cosmic rays. The problem with cosmic rays is they interact somewhere in the atmosphere not in the middle of a giant array of detectors like they ought. Cosmic rays also don't happen all that often. So while the reaction is similar the collider gives better rate and controlled location.
A1: This is research. Foreseeable applications are only used to part venture capitalists with their money. There are many ways that people justify research for the sake of research, just like art for the sake of art, but you are being lied to if they tell you there is an application.
For my money this probably has about the same chance of developing cost-efficient solar as the average bay area start-up; 0.
Link should go find more rupees.
"Stop failing the Turing test!" -- Dilbert
You obviously haven't tasted CERN coffee - they have expresso machines and its generally very good. Much more likely is "This food is offal". I remember several times going to to the coop and the three dishes of the day were things like calf's head, tripe sausage and tongue...yummmm!
---I'm a physicist (working on my PhD), but I've had one nagging question about hawking radiation noone's been able to answer (satisfactorially)
I'm a lowly EE student :) I think I understand though.
---So, the process of hawking radiation can be thought of as a particle/anti-particle pair being created near the event horizon. Suppose that one of them is juusssttt close enough to the event horizon that it falls in and the other one remains outside. We assume that (to conserve total energy) the antiparticle falls in, annihilates a regular particle trapped within the black hole and the regular particle that was just far enough away escapes. From the outside, it appears the black hole is radiating mass.
Not quite. The particle/anti-particle is actually created from the vacuum. Quantum physics allows for virtual particles to exist as a form of catalyst, however that energy debt must be paid no matter what.
Lets say one has a controlled black hole. If one was to watch the event horizon, you would see virtual particles swarming in and around the black hole. If the pair falls in, the net energy is 0. This is the case we dont care about because energy/mass is conserved. The other case is where 1 falls in and the other is ejected into space. In that case, the black hole did "eject" mass, but the energy debt must be paid. Because of that, the black hole must pay to create the pair via its own energy.
We call this effect where the black hole pays energy to create "real" virtual particles Hawking Radiation.
---A) I would think that there would be an equal probability distribution of which particle is closer to the event horizon. However, if that were the case then there would be an equal probability that normal/anti particles would fall in, and that would cause the black holes to not evaporate. We know they do, so I don't know how to rectify that. What makes the antiparticle more likely to be closer to the event horizon?
That's where you are mistaken. Overall energy is lowered when 1/2 of the pair is absorbed by the black hole. Once the black holes lose enough energy (some critical value), they explode violently. What we dont know is what exactly happens in a black hole, nor do we know what form of matter/energy is in there, but we do know that the energy debt must be paid.
---B) Suppose you were able to accrete enough antimatter that you could produce a black hole with it. Virtual particles are created on the outside. In this instance, the normal particles must fall in and the anti-particles must escape to conserve total energy. How does that happen? How can the particles see beyond the event horizon to know that's what's within?
I think you're getting hung up on matter and antimatter. They're all quarks. They all combine somehow with U, D, U-bar and D-bar, and even if they did annihilate and release energy, the energy is still trapped. And since the event horizon seems to be a sort of heisenberg shield, I dont think they need ever "collide".
That's why we're studying them cause traveling 100+ Ly is impossible for us now.
The LHC collides protons, not electrons.
Repulsion by solid matter isn't enough to stop it.
This depends on whether or not it is a charged black hole. In all likelihood it will be since it would have been produced by colliding two protons. Since EM interactions are many, many orders of magnitude above gravitational ones (calculate the difference in the gravitational vs. electric forces in an atom for an excellent illustration) I would expect a charged black hole to interact via EM far more strongly than by gravity.
"we don't really know what will happen. Period."
Bull. We don't know exactly what will happen, but that's not the same as having no idea at all. We know very well that certain things will not happen; like destroying the earth. The experiment to be performed is performed regularly by random cosmic rays in the atmosphere. We don't know what will happen in terms of the data collected by the sophisticated instruments in place at the LHC, because these instruments are not in place for those naturally occurring experiments. But for those naturally occurring experiments, certain very crude instruments are in place. Including a crude, but actually perfect detector for earth-destroying effects, which we call the earth. It's still here.
Why are we finding no extraterrestrial civilizations?
They all get to this step in technological advancement and "Black Hole" themselves?
Maybe a significant portion of existing black holes are not the results of collapsed stars, but rather previous Hadron-like mistakes of monumental proportions?
I agree, as far as "science doesn't deal with deduction, as opposed to induction."
This proof, however, lacking any experimental results or direct observation of the phenomena in question, is unquestionably a deductive proof. It's quite a simple one actually:
"If cosmic rays spawn world devouring strings/black holes, then we'd see a marked absence of quasars and neutron stars"
"We don't see a marked absence of quasars and neutron stars"
"Therefore cosmic rays don't spawn world devouring strings/black holes"
This is fricking modus tolens; it's one of the most basic deductive constructs. Saying therefore, that his proof is fallacious is perfectly legitimate.
ad logicam Claiming a proposition is false because it was presented as the conclusion of a fallacious argument.
We know very well that certain things will not happen; like destroying the earth. The experiment to be performed is performed regularly by random cosmic rays in the atmosphere.
Not quite. From what I've read, the LHC would create more-or-less stationary black holes, which if they don't evaporate, would bounce back and forth through the earth, eventually settling in the core. The cosmic ray collisions would create micro black holes traveling at high velocities, which would could go straight through the earth and out the other side, without being much affected by the planet's gravitational pull and not getting the chance to do any real damage. The article states that if this happened, then surely there'd be no old neutron stars in the universe (since, unlike the Earth, a neutron star would have enough mass to capture a high-velocity micro black hole.) I don't find that reasoning too comfortable.