Is it really possible that the Large Hadron Collider is going to accidentally end the universe? CERN says no, but every organization has a tendency to believe its own press releases. Discuss.
Copyright © 2009 by The Atlantic Monthly Group. All rights reserved.
There isn't enough power on the planet Earth to cause a black hole large enough to collapse it, or take a big chunk of it. Where CERN is building the collider, worst case scenario the electromagnetic field completely collapses without taking any energy out of their minuscule black hole. The black hole destabilizes and explodes (implodes is more accurate). Damage to surrounding areas, not globe altering.
That, or something similar, is a common answer to the so-called Fermi Paradox.
Of course they'll say there is no risk. But it seems absurd to think that we know what will happen. If we knew, we wouldn't need the LHC, would we?
Even if the chance is one in a billion, the expected value is pretty bad.
LHC possibly could do it (it being the destruction of the Earth), but the probability is so low, you have a better chance of meeting Morgan Freeman in a renovated industrial building where he grants you supernatural powers.
Events like those in the LHC do happen quite often anyways, as the universe is filled with high-energy particles that impact our atmosphere (and every other object we know of) on a continuous basis. Given that we're still here, and we don't observe astronomical objects abruptly disappearing, chances are we're pretty safe.
There is a finite non-zero probability that the Earth will be destroyed by some unknown particle or something. According to quantum mechanics there is also a finite chance that I can walk through a wall without my particles running into the wall's particles. I'm not too worried about either actually happening.
I remember seeing one of those Discovery/History channel shows on the Tunguska event. Apparently a pair of physicists theorized that the thing was the result of a small black hole passing through the earth. Of course there were tons of problems with this theory (exit event, other things that might happen if a black hole passed through the earth), but I'd like to think, like Ben, the worst case scenario is that Geneva blows up (which is worse than it sounds, given the number of IGOs headquartered there).
One of these days the doomsdayers will get their end-of-the-world predictions right and you naysayers will feel really, really stupid. Exceptionally deceased, but foolish nonetheless...
According to quantum mechanics there is also a finite chance that I can walk through a wall without my particles running into the wall's particles
This is known in scientific parlance as the Ghost Dad principle.
The fact that we observe a huge number of black holes in the universe but no other intelligent life should give us some worry about the LHC.
The fact that we observe a huge number of black holes in the universe but no other intelligent life should give us some worry about the LHC.
One of these days the doomsdayers will get their end-of-the-world predictions right and you naysayers will feel really, really stupid.
Not for long.
*Sigh* Here's a pretty good write-up:
http://arstechnica.com/news.ars/post/20080623-safety-report-latest-collider-at-cern-wont-end-the-world.html
It's worth noting that the LHC scientists don't have a spare planet handy for themselves or their families, so they're not all that likely to be engaging in risky planet-destroying experiments.
One problem with the doomsayers is that they speculate that
a) quantum mechanics is right in that microscopic black holes exist
b) quantum mechanics is wrong in that they won't instantly evaporate.
I'm a little nervous, for all my fancy-pants education. But I'm still planning to make my mortgage payments on time.
"John McCain: More of the Same": The probability isn't 1 in a billion. In fact, the probability isn't calculable, because it's based on physics operating in a way different than we expect.
I think this CERN-provided answer is fairly persuasive:
The very short answer is that these particle interactions are very high-energy by our standards, but only moderately impressive on cosmic standards. Much more energetic interactions occur in a variety of astronomical contexts, and we don't see any particularly apocalyptic consequences there.
For that matter, there are plenty of high-energy particles (called cosmic rays) floating around the universe at any particular time. It's straightforward to calculate the number of interactions between two such particles that have happened to occur near the Earth over its lifetime. This turns out to be a reasonably large number, yet apparently the world hasn't ended yet because hey, look around.
Robin Hanson recently tackled some of the same questions from a historical perspective. A longish, but interesting post worth a read to find out why his conclusion is:
"The number one lesson I take from this whole issue is that where human-caused uncertain existential dangers are concerned, the only way to get a real, serious, rational, fair, evenhanded assessment of the risks, in our modern environment, is if the whole project is classified, the paper is written for scientists without translation, and the public won't get to see the report for another fifty years."
http://www.overcomingbias.com/2008/06/la-602-vs-rhic.html
They'll be fine, as long as they don't cross the streams.
This sort of doom-saying seems to crop up every time something new is tried. The most obvious example being the school of thought that held that the first atomic bomb test would ingite the crust of the earth. And thus the end of mankind. You will observe that the crust did not ignite and we are all still here.
As for those who say "someday the doom-sayers will be right" -- well consider their track record (on small things, as well as large). If the "someday" that they are right is a billion years from now, as seems entirely possible, how wise would we be to heed them today?
Some of the superscripts got eaten in the block quote there.
Obama will change quantum physics, and we will be saved!
As Mr. Tony would say, the odds are 50-50. Either is happens or it doesn't. If it happens, we'll all know real soon if there is an afterlife.
No, Higgins, I think we're screwed if it happens, the gravitational pull is so strong even souls cannot escape.
Hmm. Hadn't considered that, but I'd still roll the dice on this one. Nothing to lose.
I love the precationary principle.
There are far greater dangers that are theoretically possible. Some songs bore into your brain and refuse to leave. If one of those was bad enough and got a lot of exposure, we would see widespread psychological dysfunction, perhaps enough to bring down the industrial society. Some would live, but those years of mass starvation, along with that damn song still stuck in our heads, would be worse than anything physicists could do.
I'm willing to give odds on it right now. If the universe ends, I'll pay out five million to one.
Wake up, people!
Stop Big Physics!
It's for the children!
No Blood for Anti-Particles!
Bring our protons home NOW!
I question the timing.
Connect the dots.
Hey hey, ho ho, Geneva will be the first to go!
(Sorry, I spent too long in Berkeley.)
We need a secular version of this:
http://www.youvebeenleftbehind.com/index-2.html
So that we can notify any survivors of the black hole.
I think I saw a movie about that...."The Philadelphia Experiment"......and everything in the movies is true, right Al Gore?
There is something about LHC that has made my thumbs twitch whenever I read about it -- even when it was in the planning stages. Not so with other particle accelerators. Can't really say why.
I do think deliberately trying to create a black hole is rather stupid. Too many known unknowns without even considering the unknown unknowns.
Even if the odds of it going wrong are miniscule, it would be the ultimate low probability high consequent event. And for what purpose?
Seriously, no one's going to make a "Large Hadron Collider" joke? Maybe involving Larry Craig and David Vitter?
Nature has been conducting particle physics experiments on the planet that are a whole lot more impressive than anything we can manage and it's been doing it for the last four and a half billion years.
If the LHC could possibly make a world-destroying event, the Earth would have ceased to exist eons ago. The Earth is here, therefore the LHC can't, QED.
Ben, you're basically right about any nano-hole evaporating immediately, but it's not going to destroy the lab. The sum of the energy you can get out of a hole is equivilent to the mass of the black hole. Any black hole that was created would have the mass of the elementary particles that formed it. While E=MC2 gives an impressive ratio when converting mass to energy, that amount of mass turned into energy wouldn't destroy the lab or even be noticable without special equipment to detect it.
This means 104 years, times 350 days per year, times 1 billions shavings each day, giving a total of 3·1015 shaves. Since nothing has happened, empirically you can state that the probability of something wrong happening has to be less than 3·10-16.
This came from CERN? That worries me -- this doesn't make sense. If I flip a new coin four times and it comes up heads all four times, does that mean that empirically the probability of it coming up tails must be less than 1 in 4?
I asked a mathematician friend of mine that question, ken, with regards to a million coin flips that all came up heads.
I expected him to say that the odds for the next flip would be precisely 1:2 but he surprised me by saying that if a coin comes up heads a million times in a row, the odds are that the coin, itself, is not a fair coin (i.e., that it has an even chance of coming up heads or tails) and that we should, therefore, bet that the next flip will also be heads since it's much more probable that the coin is either rigged or defective.
I think that pertains to the shaving example. Even though we can't deductively confirm that shaving won't destroy the planet, the odds lend themselves well to the deductive conclusion that it's so vanishingly unlikely that we shouldn't concern ourselves with it.
a semi-relevant quote from Life, the Universe, and Everything by Douglas Adams.
(Arthur is about to cause the destruction of the universe.)
He hoped and prayed that there wasn't an afterlife. Then he realized there was a contradiction involved here and merely hoped that there wasn't an afterlife. He would feel very, very embarrassed meeting everybody.
Inductive. The odds lend themselve to the inductive conclusion is what I meant to say.
Oy.
Good News!
If they are wrong, we will never know it.
(Variation on the adage "If you hear the bang, you have nothing to worry about".
I am not a physicist or anything close to it, but it seems like the scale of energies is such that the probabilities of one of the reactions to the gorebal warming thing will plunge us into the stone ages again are much higher, ant that outcome would be a lot worse.
I expect the collider to turn into a giant donut.
Andrew,
That's a bit different, and isn't really a special case. You go in with a probability that the coin is rigged or flawed (which could be high or low depending on the provenance of the coin). Then it's just a matter of comparing the probability of x successive Heads flips to the probability of the coin being defective. Doesn't really help CERN here AFAICT.
This came from CERN? That worries me -- this doesn't make sense. If I flip a new coin four times and it comes up heads all four times, does that mean that empirically the probability of it coming up tails must be less than 1 in 4?
If you can show me a shaver that has empirically known 50/50 odds of destroying the universe upon being activated, then the question is moot, because I'll show you a weapon that will allow us to take over the world. Supervillain style.
The CERN example only compares to a coin toss if we are considering the probability that the coin can land on a hard level surface and somehow sit on its edge at a 45-degree angle indefinitely. While it can't be disproven that a fundamentally unique confluence of physical phenomena might permit such an outcome at some time and place, there are potentially several hundred billion coin tosses against it already.
There was some long chain of back and forth about the chance of global destruction that I was reading that completely hinged on the formation of black holes. Keeping it short the conversation went like this.
A: This will destroy the Earth when it makes a black hole.
B: Black holes of the size the LHC will create already go through the Earth all the time.
A: Those black holes are going really really fast and can't destroy the Earth. The ones the LHC make will be going slow enough to destroy us.
B: Even if it's going slowly these black holes are so small they almost definitely won't interact with any matter since most space is empty.
A: But they could...and then we would be dead.
B: These black holes also hit neutron stars and neutron are ALL mass without any space for the black hole to escape from. We see a lot of neutron stars. If we see a lot of neutron stars then it is impossible for a black this small to turn into something scary when they can't even keep themselves going on what is basically a perfect fuel source in the form of a neutron star. If they destroyed neutron stars, we would never see a neutron star...they would all be dead. The amount of fuel the Earth provides definitely isn't enough to destroy us.
...and that's where it ended. I'm not an astronomer, but that seems like a pretty good "no, we won't all die" endorsement.
wasn't there an Arthur C. Clarke short story about this kind of thing?
If you can show me a shaver that has empirically known 50/50 odds
Not sure what this has to do with anything. The passage quoted above said that after X repetitions, result Y has not happened, so empirically the odds of Y happening must be less than 1/X. This is simply incorrect, as my little coin flip example shows.
If you're responding in part to my "That worries me" intro, that was just snark -- I'm not actually worried, regardless of this bit of innumeracy.
what Scott Aaronson said: http://www.scottaaronson.com/blog/?p=334
As the great philospher-poet said "I don't believe we are on the eve of destruction"
Not to worry lowly boggies, It is my destiny to die at the age of 80 by the hand of a jealous husband, decades from now, so you are all safe.
Ken B,
Your analogy with the coin does not really explain much. The problem is that you already have enough experience with coins to know that flipping them will give you 0.5 odds of either heads or tails, and if you get 4 heads in a row, you can dismiss that result as a fluke. But suppose you are an alien from space and have never seen a coin before, and have no idea how it will behave when flipped. If you flip it 4 times and get heads 4 times, it will be rational for you to conclude that the next time you flip it, more likely than not you will get another heads. It is what we call inductive reasoning.
It's basically already speculative to believe that the LHC will create micro-black holes. It's definitely not designed to create black holes, as one commenter above seems to think. It's supposed to create high energy collisions that make all sorts of "virtual particles" that flicker in and out of existence very briefly, leaving behind a bunch of high-energy subatomic particles that are less exotic than black holes and rapidly decay into even less exotic subatomic particles. Detecting these decay products tells us something about the physics at high energies.
The people behind this lawsuit (who made a previous lawsuit against RHIC, which didn't blow up the world, either) are not very far removed from the people who send you email spam about Free Energy and put crackpot videos about fusion power on Youtube. They don't have a good answer to the fact that high-energy cosmic rays already create these kind of subatomic interactions every day in the upper atmosphere. The LHC is designed to make more of them and in a place where the decay products can be detected more easily.
On the other hand, perhaps particle physicists could get more funding by persuading the Department of Homeland Security to bankroll a defense against cosmic rays.
The LHC does not perform collisions more energetic than those that occur regularly in nature; its value is that it performs high-energy collisions in a time and place where we can set up lots of scientific instruments to see what happens in the first few milliseconds.
So, if LHC-level collisions create black holes that don't decay, then there are uncountable numbers (orders of magnitude more than trillions) of such black holes in the galaxy.
Now, neutron starts are objects with the same density as an atom's nucleus. While a fast-moving black hole with a sub-atomic event horizon could pass through the Earth quickly without hitting (much) matter, and thus not growing very much, the same is not true in the case of a neutron star. A microscopic black hole hitting a neutron star would be slowed down significantly and consume significant mass, and would almost certainly consume the whole thing. The "almost" is low enough and the number of expected microscopic black hole large enough that the maximum number of neutron stars detectable in the sky at once would be usually zero and very occasionally one, for a very brief period.
So, the existence of neutron stars tells us that there are not more-than-trillions of non-decaying microscopic black holes in the galaxy. If there were, all the neutron stars would be gone. The lack of large numbers of non-decaying black holes tells us the LHC-level collisions don't create non-decaying black holes.
As far as blowing up Geneva, that isn't going to happen, either. Any evaporating microscopic black holes that are created will release no more energy through decay than the energy that was used to create them in the first place. Accordingly, the evaporation of an LHC-created black hole will release no more energy than the collisions the LHC is designed to produce.
So, the net is, you have far more important things to worry about, like a meteorite hitting you in the head as you read this.
(All of this is in my opinion and as far as I know, of course)
The worst that could happen is merely destroying the Earth. The LHC will be operating at energies that cosmic rays routinely exceed, and if cosmic rays haven't destroyed the universe yet, the LHC won't.
That said, destroying the Earth is quite unlikely. The fear is that these collisions will create extra-funky heavy-yet-stable particles which will then orbit around inside the Earth, screwing things up. Cosmic rays, again, do this all the time... but cosmic rays produce particles which are screaming through the Earth at way, way above escape velocity. The LHC particles (near as I know) will not make escape velocity, and if they are stable, will pass through the Earth over and over, not just once.
Worst case is LHC makes a stable black hole which then swallows up everything. I won't lose any sleep over that. It's just... so implausible. Black holes of that size don't last a nanosecond. They get torn apart instantly, before they have time to cause any trouble. Stephen Hawking has details. There are other, not so bad, possibilities in between. For example: strangelets might be as dangerous as a black hole, but are probably even less likely. Do strangelets decay in the same way as small black holes? Anyone?
I'm worried about global warming, cancer, and heart disease... but not about this. I see why people worry about black holes, but I respectfully disagree.
It's another neutron star problem. If high-energy events can create survivable strangelets and strangelets do catalyze conversion of normal matter into strange matter, then neutron stars shouldn't exist, only quark stars. After all, neutron stars get hit by cosmic rays all the time. Since neutron stars do exist, high-energy events on neutron stars either don't create strangelets, or the strangelets don't convert nucleons.
"Where is the 'Kaboom!'? There was supposed to be an Earth-shattering 'Kaboom!'".
No.
Well what are we going to do about it? Surely we don't want to expand the nanny state to cover such petty things as disallowing the destruction of the universe.
I mean in some philosophical sense, isn't human existence ultimately just a race to see who can destroy the universe (or at least make extinct the species homo sapien) first? If the folks at the LHC succeed, we'll have to give them their due credit right before we go.
It doesn't really matter. If we don't do it, then someone else will -- if not now, then pretty soon. It was the same with the A-bomb.
Let's assume that there is something significant and potentially deadly about the universe that threatens the Earth's existence. If the threat is not potentially controllable, then it is irrelevant. If the threat can be avoided, then the most important thing is to identify and analyze the threat as soon as possible. Science is a risk at some level, but, run by responsible people and nations, it is much more of a benefit. But once again, we have a tiger by the tail. If we don't do it, where do we get the authority to stop others from doing it.
Unless we have good evidence for the danger, it will be difficult to stop the next attempt. After sixty some years even the nuclear jinn is slipping out of the bottle despite our best efforts. And we know about those dangers.
Is there any conceivable scientific experiment that could be conducted in a relatively small space (smaller than Manhattan, say) that actually could have a credible chance of ending whatever it is exactly that the LHC supposedly might end?
As Lubos Motl (at The Reference Frame blog) pointed out, the universe has been generating much higher energy events for on the order of 14 Billion years and it still exists.
Mike M.