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Black Holes From the LHC Could Last For Minutes
Posted by
kdawson
on Fri Jan 23, 2009 11:05 AM
from the becoming-greyer dept.
from the becoming-greyer dept.
KentuckyFC writes "There is absolutely, positively, definitely no chance of the LHC destroying the planet (or this way either) when it eventually switches on some time later this year. And yet a few niggling doubts are persuading some scientists to run through their figures again. One potential method of destruction is that the LHC will create tiny black holes that could swallow everything in their path, including the planet. Various scientists have said this will not happen because the black holes would decay before they could do any damage. But physicists who have re-run the calculations now say that the mini black holes produced by the LHC could last for seconds, possibly minutes. Of course, the real question is whether they decay faster than they can grow. The new calculations suggest that the decay mechanism should win over and that the catastrophic growth of a black hole from the LHC 'does not seem possible' (abstract). But shouldn't we require better assurance than that?"
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News: Why the LHC Won't Destroy the World 508 comments
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."
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Another Way the LHC Could Self-Destruct 367 comments
KentuckyFC writes "Just when you thought it was safe to switch on the LHC (though it won't be for a while yet), another nightmare scenario has emerged that some critics worry could cause the particle accelerator to explode. The culprit this time is not an Earth-swallowing black hole but a 'Bose supernova' in the accelerator's superfluid helium bath. Physicists have been playing with Bose Einstein Condensate (BECs) for over 10 years now. But in 2001, one group discovered that placing them in a powerful magnetic field could cause the attractive forces between atoms to become repulsive. That caused their BEC to explode in a Bose supernova — which they called a 'Bosenova,' a name that fortunately did not catch on. This was little more than a curiosity when only a microscopic blob of cold matter was involved. But superfluid liquid helium is also BEC. And physicists have suddenly remembered that the LHC is swimming in 700,000 liters of the stuff while being zapped by some of the most powerful magnetic fields on the planet. So is the LHC a Bose supernova waiting to go off? Not according to the CERN theory division, which has published its calculations that show the LHC is safe (abstract). They also point out that no other superfluid helium handling facility has mysteriously blown itself to pieces."
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Miscalculation Invalidates LHC Safety Assurances 684 comments
KentuckyFC writes "In a truly frightening study, physicists at the University of Oxford have identified a massive miscalculation that makes the LHC safety assurances more or less invalid (abstract). The focus of their work is not the safety of particle accelerators per se but the chances of any particular scientific argument being wrong. 'If the probability estimate given by an argument is dwarfed by the chance that the argument itself is flawed, then the estimate is suspect,' say the team. That has serious implications for the LHC, which some people worry could generate black holes that will swallow the planet. Nobody at CERN has put a figure on the chances of the LHC destroying the planet. One study simply said: 'there is no risk of any significance whatsoever from such black holes.' The danger is that this thinking could be entirely flawed, but what are the chances of this? The Oxford team say that roughly one in a thousand scientific papers have to be withdrawn because of errors but generously suppose that in particle physics, the rate is one in 10,000."
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It's Crazy (Score:5, Funny)
Folks I don't want to hear say oops (Score:5, Funny)
1. My Barber
2. My urologist during my vasectomy.
3. The LHC scientists during the first collisions.
Re:Folks I don't want to hear say oops (Score:5, Informative)
Parent
Re:Folks I don't want to hear say oops (Score:5, Interesting)
I think that pretty much sums up the way that the scientists on these kind of projects really think about these things, and I find it reassuring. They are just as unenthusiastic about the prospect disappearing into nothingness as you are. They are smarter than me. They are also almost certainly smarter than you. If they are comfortable enough to joke/make bets then I'm not worried.
Parent
Re:Folks I don't want to hear say oops (Score:5, Funny)
Enrico Fermi, who won the Nobel Prize for Physics in 1938 for his work on nuclear fission, offered side odds on the bomb destroying all life on the planet.
Assuming he's betting on the "No" side, he probably should have got a prize for economics too. If you're right -- you win money. If you lose -- everyone's dead anyway so you don't have to pay! Its a win-win proposition.
(Ok maybe win-win isn't the right term here)
Parent
I say "go for it!" (Score:5, Funny)
If they're right the benefit to humanity could be enormous.
If they're wrong then it's the end of the economic crisis, unemployment, conflict in the Middle East and world hunger.
So, on balance ... I think they should do it.
Parent
Re:I say "go for it!" (Score:5, Funny)
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Re:Folks I don't want to hear say oops (Score:5, Funny)
I said it before: Lake Hadron. New shoreline real estate for sale, soon.
Don't mind the Schwarzchild radius, come on in!
Parent
Re:Folks I don't want to hear say oops (Score:5, Funny)
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Re:Folks I don't want to hear say oops (Score:4, Funny)
How can an LHC scientist say oops if their vocal cords have entered another dimension of space and time?
At the LHC's first collisions, a black hole forms....
scientist: Oops... OMFG! Call the President!
evil voice from inside the black hole: What good is a phone call if you are unable to speak?
Parent
Re:Folks I don't want to hear say oops (Score:5, Funny)
Yes. At some point in the future, I'm fine with the universe unfolding like so:
Mother: Tottle, do NOT do that!
Child: But mom, they are just small ones.
Mother: You remember what happened to the humans, don't you?
Child: They danced funny?
Mother: Besides that...... (hand on hip)
Child: (face frowning slowly) Yes mother, they blew up the southeast quarter of the galaxy experimenting with black holes.
Mother: that's right Tottle. It's all fun and games till chunks of the galaxy go missing. Your father will NOT be impressed if he can't find our house after he gets off work tonight.
Child: yes mother
Mother: now put your physics set away and make your bed.
Child: yes mother
Yes, I'd be happy to be a footnote in the history of the universe as an example of what you really shouldn't do with your Acme Physics set that you got for your birthday.
Parent
Re:Folks I don't want to hear say oops (Score:5, Funny)
Four minutes?! I'll be damned if they make black holes that last longer than I do!
Parent
Re:Folks I don't want to hear say oops (Score:5, Funny)
I'm hoping it'll suck more than my wife.
Yeah... me too.
Parent
Its all okay. Nothing to see here. (Score:5, Insightful)
Well its good to know that despite their uncertainty about the the data, they are absolutely certain of their conclusions.
Re:Its all okay. Nothing to see here. (Score:4, Informative)
Even if the black holes lasted indefinately, their cross sectional area is too small to pick up any significant amount of matter. The Earth would be swallowed up by the sun long before the black hole began to threaten Earth in any way.
Parent
Re:Its all okay. Nothing to see here. (Score:5, Informative)
These black holes aren't going to have appreciable gravitational pull, and they aren't going to have appreciable cross section to actually absorb matter.
The truth is, we already know darn well what is going to happen macroscopically. We know physics pretty darn well. Its the very fine details that we aren't sure about.
Parent
Well... (Score:5, Insightful)
Fire it up, boys!
Re:Not so fast there old chap! (Score:5, Funny)
In theory.
Parent
cosmic rays (Score:5, Insightful)
I thought that this entire line of doomerism had been dispensed with thanks to cosmic rays.
Since cosmic rays are striking the earth all the time, and a decent percentage of them have a much higher energy level than anything the LHC can produce, we should have already seen such a phenomena.
?
Re:cosmic rays (Score:5, Interesting)
If such stable black holes were creatable / existed, we should see rather remarkable things with old white dwarfs and neutron stars, which would be greatly affected by such energy sources.
Parent
Re:cosmic rays (Score:5, Interesting)
Parent
Couldn't agree more... (Score:5, Funny)
Small black holes are far less dangerous than made out to be.
A while back we had a family of small black holes living in our basement, and I found that if you didn't bother them, they wouldn't bother you.
The wife wanted rid of them, but I said no, they're not doing any harm to anyone - and anyway we never used that part of the basement.
Eventually they just moved on.
Parent
Re:cosmic rays (Score:5, Informative)
Jeez - read the abstract. Its a calculation based on a theoretical model using some very speculative physics for which there is NO EVIDENCE WHATSOEVER. Really. Ignore it.
The main thing to keep in mind is, cosmic rays have energies vastly higher than the LHC. If the LHC could produce black holes, then there would be black holes floating around everywhere.
Parent
Re:cosmic rays (Score:5, Insightful)
There is no need for comments on this article other than the parent. In fact, this article should just be put into idle.
As a physicist, this whole thing has been an embarrassing reminder of just how bad physicists are at public relations and the failure of many people to think logically. I'm not the biggest fan of LHC, but I'd like to see some intelligent criticism out there (Is this really where we should be putting our smartest scientists? Are particle accelerators the best way to do this measurement?), not this junk.
Parent
Re:cosmic rays (Score:5, Insightful)
> Is this really where we should be putting our smartest scientists?
What gives us the right to decide where to 'put' 'our' smartest scientists? They belong to themselves, right? It is their choice what to do with their brains (cure cancer or get drunk or work at the LHC).
If you insist on asking a question I guess you could ask 'Do we really want to fund the LHC?'.
Parent
Re:cosmic rays (Score:4, Informative)
Actually cosmic rays don't fully replicate the black hole problem. Keep in mind that a black hole in the LHC would be fed for some bit of time by the stream of high energy particles in the LHC before it leaves the beam path and that black holes apparently have a relatively large cross section compared to subatomic particles. In theory, if you can feed a black hole more mass than it loses, you'll eventually grow it large enough to cause a problem, if you drop it into the Earth.
Having said that, neutron stars are a better case study. They have densities far above that of Earth. For example, the average density of Earth is somewhere around 5.5*10^3 kg/m^3, presumably a little more in the core and around 2.5-3 kg/m^3 near the surface (I guess). The surface of a neutron star [wikipedia.org] can have densities around 10^9 kg/m^3. That's almost a million times as dense. The interior can be far higher, somewhere above 10^17 kg/m^3. That's a factor of 10^14 more. Glancing at wikipedia [wikipedia.org], the power output of a black hole is proportional to the inverse square of the mass. The cross-section area is proportional to the 2/3 power of the mass (mass is proportional to volume which is proportional to 3/2 the power of the cross-sectional area). That leads to the tricky observation that the ratio of mass sucked to mass lost is proportional to 8/3 power power of mass. So a black hole formed by such a cosmic ray immediately interacts with mass roughly 10^6 denser than the surface of the Earth. Neutron stars obviously have a massively greater acceleration (10^12 stronger roughly), so velocities will be a lot faster. Let's suppose that means that a black hole on a neutron star intercepts 10^18 (=10^12 * 10^6) times as much mass as it would on Earth. For a black hole on a neutron star to have the same ratio of mass in to out as one in Earth would have, it'd need a mass almost 10^7 times smaller.
Some natural cosmic rays are known to have energies above 10^20 eV. In comparison, the energy of lead ions (the highest energy particles mentioned in the wikipedia article) in the LHC will be somewhere around 10^15 eV. At a stab, that means black holes in neutron stars ought to form with initial masses of around 10^20 eV and dissipate, else the neutron star would rapidly go away. So to generate black holes with equivalent mass in/out ratios to those on a neutron star generated by the most powerful cosmic rays we've observed, we'd need around 10^12 lead ion particles crammed into the black hole to duplicate a black hole we know dissipates on the surface of a neutron star. While there's probably that many in the beam, it doesn't strike me that the black hole will intercept many of them before it is knocked out of the beam path. The black hole might even escape Earth's gravity altogether since it is likely to start with a velocity that is a significant fraction of the speed of light. I ignore the initial velocity in the above calculation because the speed has to slow to below escape velocity before there is a problem of black hole growth.
Parent
Re:cosmic rays (Score:5, Interesting)
> What happens if one of these black holes happens to intercept a spacecraft as it leaves
> or re-enters the atmosphere? Does it do significant damage?
No. Try to understand how small these holes would be. They are so tiny that in the unlikely event that they hit the nucleus of an atom they would almost certainly pass through with out interacting at all with any of the subatomic particles there. Your spacecraft is going to be hit by cosmic rays with far more energy and with a far higher probability of interacting.
Parent
What could possibly go wrong? (Score:5, Funny)
Re:What could possibly go wrong? (Score:5, Informative)
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Re:What could possibly go wrong? (Score:4, Informative)
Not as much fallout as what is created by burning coal to create electricity.
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Assurances (Score:5, Informative)
But shouldn't we require better assurance than that?
What better assurance can we get than mathematical formulas? Unfortunately the only other way to find out is to run an experiment, right? I just hope their formulas and the assumptions they are based on are correct.
Space Madness (Score:5, Funny)
And there's no possible way that Stimpy would be stupid enough to press the beautiful, shiny button - the jolly, candy-like button.
and nothing of value was lost?
Storm in a very, very tiny teacup (Score:5, Insightful)
Well, duh! (Score:5, Funny)
those mini black holes were up in the air, not next to the earth you ninny.
sheesh, next thing someone will make a video game with this scenario
Parent
Re:Well, duh! (Score:5, Interesting)
Parent
Advanced Alien Civilizations (Score:5, Funny)
Re:Advanced Alien Civilizations (Score:5, Interesting)
Parent
Bruce Campbell at the LHC (Score:5, Funny)
Yeah, I would really feel a lot better if the LHC deployed Bruce Campbell, with a shotgun during those Black Hole experiments:
Evil Witch/Black Hole: "I'll swallow your soul! I'll swallow your soul!"
Bruce points his shotgun at the Evil Witch/Black Hole:
Bruce: "Swallow this."
*Blam*
seconds and minutes (Score:5, Funny)
when they say seconds and minutes is that in normal earth time or according to the time inside the micro event horizon?
Absolutely, positively, (Score:5, Funny)
The Quantum Make a Wish Foundation (Score:5, Funny)
Everyone wins a free trip to France.
Gravity still applies (Score:5, Insightful)
A black hole is just the gravity well of a given mass compressed into a sufficiently small space. In this case, the given mass is miniscule, so very little (practically nothing, hence the "evaporation" issue) will be drawn to it.
You have more to worry about from the gravitational pull of your shoes.
Screw mini-black holes. (Score:5, Funny)
It's the ice-9 strangelets that have me worried.
Cite the original paper (Score:4, Informative)
If you bothered to go past the Slashdot summary of the arXiv blog summary of the paper's abstract summary, and actually RTFA by Casadio et al. [arxiv.org], you would find the following:
and also this:
Possibly, potentially, maybe, under certain conditions, they might be longer lived than expected. They still can't grow.
Go back to worrying about your 401Ks.
Even if it does so what? (Score:5, Informative)
If the LHC manages to create mini blck holes, let's be clear here, tese will be very very mini. A black hole weighing what? Same as a couple atoms of carbon?
Consider that even if matter collapses to a singularity, its gravitational effect is still just proportional to its mass. Given that the LHC is a vacuum where the collisions are occuring, the blackhole could only ever mass the sum total of the mass of the particles used in the collision. From a casual outside observer you wouldn't even notice, and the black hole would decay before it could acquire more mass.
Cosmic Rays anyone? (Score:4, Informative)
The most energetic particle that the LHC can create is 574 TeV/particle lead nuclei. Nature has been bombarding our solar system with a significant flux of particles as powerful as 100 million TeV for as long as it's been around. If it was possible to spawn a black hole capable of consuming a planet from a collision with a particle a mere thousand TeV in energy, then it is all but certain that we would have seen every large body in our solar system converted from billions of years of bombardment from cosmics ray 100,000 times more energetic (caveat: much more energy is available for consumption into a black hole should two particles collide "head-on" with opposing momenta versus a fast particle with a stationary target).
Though, the above reasoning does not exclude the possibility that black holes that may last minutes but yet not consume planets.
~Ben
"Answer first, experiment second" -- the FRAK? (Score:5, Funny)
I find it hilarious how people say, "Before we run an experiment, we need to know what will happen!" Hello, McFly! You run experiments to FIND OUT WHAT WILL HAPPEN. That's, uhm, the whole FRAKING DEFINITION OF THE SCIENTIFIC METHOD! You can do the math, you can form theories, you can hypothesize... but you never know FOR SURE until you flip the switch.
People like the OP were probably standing around in caveman days, saying, "Ugh. No make fire. What if fire is monster, kill everyone? Bad thing. Not make fire unless know not monster."
Bogus (Score:5, Informative)
Groups of high energy particles striking each other is not rare in nature. It happens all the time, right in our own atmosphere, on the surface of the moon.
This is all Chicken-Little nonsense.
Parent
Agreed, this is silly. (Score:5, Informative)
Since they will not have immense mass to apply to the particles, they will have to apply truly immense amounts of energy (E=mc^2). Should they actually achieve a 'black hole', it will have the same amount of gravitational attraction as it did before.
I think I will spend my time worrying about more likely problems, like cholesterol and cancer.
Parent
Re:Bogus (Score:5, Interesting)
Actually, cosmic rays, which regularly (read: constantly) enter our atmosphere, have energies up to 10^20 eV. The LHC uses 7 TeV protons and ~500 TeV lead nuclei. That's on the order of 10^12 to 10^14 eV.
So, you have it backwards. We don't produce particle at anywhere near the energy they're produced in nature.
Parent