Help me understand...
April 1, 2010 3:34 PM   Subscribe

Could the LHC cause earthquakes?

Please don't laugh. It will probably be a challenge for those whose forte is physics to explain it in a way a humanities major could understand, since I have very little physics background. To you this may seem like a dumb question, but it is an honest one.
It seemed there has been more earthquakes since the LHC began this year. Could there be a direct correlation?
Here is my reasoning: the LHC is underground and the collision is more than three times what has previously been accomplished. All my life I have heard of the "power of the atom." That simply splitting the atom was what caused the fission (?) of the A-bomb of Hiroshima. If splitting the atom caused such a reaction, what would be the power released from colliding them?
As a female, if I want to move a heavy sofa I give it a little push with my hip and get momentum going until it is moved.
Could the collision cause such a "little push" to the earth's plate tectonics that it "scoots" them over a little?
posted by srbrunson to Science & Nature (20 answers total)
 
The collisions that take place in the LHC have energies in the range of 10 TeV. This is enough energy to power a 100 W lightbulb for about a millisecond. It's not a lot of energy on a human scale, let alone a geological scale.
posted by mr_roboto at 3:43 PM on April 1, 2010 [1 favorite]


Additionally, cosmic rays impinge on the earth with this sort of energy all the time. (for those who want to quibble, no, not in the rest frame; but this is only really an issue for what sort of products such a collision might make, not for how their energy might affect things like earthquakes. As far as those products go, e.g. the black hole scenario, those being serious issues are ruled out by rays impinging on much denser objects like neutron stars all the time, and nothing horrible having happened).

What the LHC is doing is new, for humans, and new in a controllable fashion, but not new in a general sense.

A good place to find answers to questions about LHC is the FAQ page. I didn't find anything specifically about earthquakes, but maybe I didn't roam long enough.
posted by nat at 3:53 PM on April 1, 2010


When you push the sofa you don't accidentally move some total other sofa on the other side of the room. You move the one you're pushing against.

If the LHC released enough energy to move a tectonic plate it would release it locally, at the LHC. That would destroy the facility that the LHC is in.
posted by eeby at 3:54 PM on April 1, 2010


There is absolutely no connection. Mr roboto's explanation is really the big and small of it: the energy is huge compared to the masses involved, but on a grand scale, very small.

As far as the earthquakes, there are always earthquakes. But when they start hitting places that are less prepared to prevent related disasters (Haiti, for example), they're gonna get a lot more press.
posted by wooh at 3:55 PM on April 1, 2010


The A-bomb involves trillions and trillions of atoms splitting. The LHC splits one (or two maybe?).
posted by EndsOfInvention at 3:56 PM on April 1, 2010 [1 favorite]


All my life I have heard of the "power of the atom." That simply splitting the atom was what caused the fission (?) of the A-bomb of Hiroshima. If splitting the atom caused such a reaction, what would be the power released from colliding them?

The highest energy particle collision at CERN had an energy of 10 TeV. That is equal to about 1*10^-6 Joules. The atomic bomb that was dropped on Hiroshima had the destructive power of 13 kilotons of TNT or 5.4*10^13 J.

That means that the bomb over Hiroshima was 5.4*10^19 times more energetic than the LHC's collision.

Thats 54 followed by 18 zeros times more energetic.
posted by rancidchickn at 3:57 PM on April 1, 2010 [4 favorites]


The A-bomb involves trillions and trillions of atoms splitting. The LHC splits one (or two maybe?).

The LHC doesn't split any atoms. It collides protons, at collision energies on the order of 10 TeV. The collision rate is about 600 million/second. This gives a total power of about 100 J/s. That's 100 W: a light bulb.
posted by mr_roboto at 4:03 PM on April 1, 2010


That simply splitting the atom was what caused the fission (?) of the A-bomb of Hiroshima.

Actually, it was the splitting of something like 1015 atoms. (Actually, I think it was even more than that, but I don't have a handy reference. The Nagasaki bomb comtained about 10 kilograms of plutonium 239. If I did my math right, that's 2.5*1025 atoms, and a fair percentage of those split when the bomb went off.)

Atoms in your body "split" every day. You contain radioactive potassium 40 and radioactive carbon 14. Notice that their atomic events haven't cause your body to explode.
posted by Chocolate Pickle at 4:04 PM on April 1, 2010


You don't need to understand particle physics, fission, or nuclear reactors to know that the LHC can't move a tectonic plate, you just need Newton's 3rd Law of Motion. If you want to push your sofa, you have to push against the floor with your feet in the opposite direction (like a car), or attach yourself to the sofa and throw a bunch of matter in the opposite direction (like a rocket).

The LHC isn't spewing huge amounts of matter like a rocket, and it's not in a position to push against the plate by pushing against something else, thus cannot move that plate even if it had the energy to do so.

On the scale of energies involved, the Chilean earthquake released about 66.3 exajoules. You don't see the exa- prefix very much because it's so fucking huge - over 300 times more energy than the biggest atomic bomb ever detonated. Compared to the 1.12 microjoules at the LHC, there are 25 orders of magnitude in difference. This is literally like considering if spitting in the ocean would cause sea levels to rise.
posted by 0xFCAF at 4:22 PM on April 1, 2010 [4 favorites]


To add onto what others have said:

The LHC uses an incredible amount of energy to very precisely align and accelerate protons. BUT, that doesn't mean all that energy is present in the photons when they collide.

The problem with accelerating matter (such as protons) very very fast is that, the closer you get to the speed of light, the more energy you have to put into your matter to get it to go faster. In fact, the energy required approaches infinity as your matter approaches the speed of light. That's because the accelerated matter is constantly bleeding off energy in the form of photons. So most of the energy used by the LHC doesn't go into the collisions themselves. It ends up, more or less, as waste heat.

The other thing to keep in mind is that, while 10 TeV is not much on human scales, all that energy is being concentrated into an infinitesimally tiny space. It's causing some real unspeakable carnage on the atomic scale, but aside from the radiation produced, it's not affecting the surrounding matter much at all. I doubt it would even produce an audible noise or vibration.
posted by dephlogisticated at 4:38 PM on April 1, 2010


In fact, the energy required approaches infinity as your matter approaches the speed of light. That's because the accelerated matter is constantly bleeding off energy in the form of photons.

No, it's because the mass of the proton also increases and tries to limit at infinity.
posted by Chocolate Pickle at 5:07 PM on April 1, 2010


No, it's because the mass of the proton also increases and tries to limit at infinity.

I think I'm confusing two related things.

I was thinking of synchrotron radiation, which I believe is due to the interaction of the accelerated matter with the magnetic fields that are accelerating it.

What you're referring to is the increase in relativistic mass that occurs during acceleration due to the good 'ol E = mc2.

To make matters more confusing, I think the former effect is due to the latter. If the accelerated matter was moving in a straight line, it wouldn't need to interact with any external magnetic fields, and (I think) only the latter effect would be present. But because high-speed particle accelerators move matter around in a circle, there must be constant interactions of the accelerated particle with the magnetic fields deflecting it. Those interactions become more and more powerful as the relativistic mass of the particle increases, and is an increasingly-limiting energy drain as v approaches c. But I'm not really clear on how it compares, in scale, to the effects of the increase in relativistic mass alone.

I am not a physicist (IANAP).
posted by dephlogisticated at 6:17 PM on April 1, 2010


The large hadron collider spins lumps of matter in a giant five-mile circular underground tunnel at tremendous speed which would cause it to wobble like an unbalanced load in a washing machine on spin cycle, threatening to tear the earth apart. However they cleverly got around this by spinning two lumps of matter in opposite directions to balance things out. Actually, I just made all that up.

Seriously though, the descriptions above of the small amount of energy in an individual proton neglects the fact that there are hundreds of trillions of protons circulating at one time. The combined energy is said to be the equivalent of a train moving at 200 kilometers per hour (about 350 megajoules). This energy is confined to a beam about the width of a human hair. That concentration of energy could do some serious damage.

It turns out that shutting down the beam is a big problem. How do you stop a speeding train in just a few feet and dissipate all of that energy? The energy in the beam would be enough to melt a 500 kg block of copper. They do it with a beam dump. The beam dump is a block of solid graphite 8 meters long and weighing about 10 tons, surrounded by 1000 tons of concrete shielding. Why use graphite instead of something denser like lead? Because it is just like the crash cage of a car which is designed to crumple in a controlled manner to slowly dissipate energy. A lead block would stop the beam too quickly, in less than a meter, causing the lead to melt. The graphite block stops the beam over a longer distance, spreading out the energy. Even so, there are other steps necessary to protect the graphite. Before hitting the beam dump, dilution magnets spread out the beam from its diameter of a hair to about 1.5 mm. Then when it hits the graphite target, the beam is steered in a spiral on the face of the target so that all of the energy doesn't bore into a single spot, sort of like avoiding burn in on a plasma TV. Even so, areas of the graphite get up to 750 degrees centigrade.

So for the original question what this means is that in the worst case, the energy in the beam amounts to a high speed train crash, not something that is going to effect the earth in any significant way.
posted by JackFlash at 6:26 PM on April 1, 2010 [5 favorites]


Congratulations- you did it! You all explained what was happening in a simple enough way to put my mind at ease and encourage further study. Will probably read through the answers a few more times as well. Thank you!
posted by srbrunson at 8:34 PM on April 1, 2010


All my life I have heard of the "power of the atom."

The thing that makes a nuclear bomb so devastating is that it initiates a chain reaction: the act of splitting (or fusing, depending on the design) two particles spits out one or more energetic particles that each then fly off and cause the same thing to happen again. The classic metaphor is a big box completely lined with mousetraps, each with a ping-pong ball resting on the spring-loaded arm. Dropping one ping-pong ball into this box sets off one mousetrap which sends two ping pong balls flying which each set off one more mousetrap and in very short order the whole thing is flying ping-pong balls. In a nuclear bomb the goal is to get this runaway condition to happen by concentrating and confining forces in a small area, so that just a little bit of trigger energy sets off this avalanche of activity that consumes the entire fuel, which can be on the order of kilograms of mass.

In a particle accelerator you're just shooting a handful of particles together and observing the fireworks when they collide. There are no "several kilograms of fuel" to fission or fusion and the conditions to reach criticality are not present.
posted by Rhomboid at 12:27 AM on April 2, 2010 [1 favorite]


0xFCAF is basically right, but exaggerates slightly: The Wikipedia page's operational challenges section has correct stored energy data, helpfully giving TNT equivalents. Note that the greatest danger in a seismic respect really comes from operating a huge number of superconducting magnets underground, the beam energy is below 10% of that.

If you intentionally blew up the entire thing (probably doable if you're determined and understand the machine better than even the people operating it currently do) while in nominal operation, you would get a rather impressive underground explosion, and I assume you could detect that with a seismometer a fair distance away. However, this is a contrived example and won't happen.
posted by themel at 1:44 AM on April 2, 2010


Actually, it [Hiroshima] was the splitting of something like 1015 atoms.

I did a back-of-the-envelope calculation and got about 2*1024 atoms. (1015 atoms of 235U is only about 390 nanograms.)
posted by DevilsAdvocate at 9:06 AM on April 2, 2010


Continuing to read and process all the impressive answers you all have written.
Although pushing a sofa on one side of the room won't cause a sofa on the other side of the room to move, the vibrations can knock a picture off the wall.
Have not read the linked Q&A page yet. After multiple readings uncertainty is creeping in...
Do not want to be overly concerned re: large underground magnets and the differing answers on the power contained in the LHC, but it would also be stupid to not learn more to clear things up in my mind. Any further help is welcome.
posted by srbrunson at 3:20 PM on April 3, 2010


I'll echo what others have said, in that the LHC has nowhere near enough power to cause an earthquake, even assuming a maximally catastrophic malfunction. But for the sake of argument, let's look at this from a different angle. The LHC could only cause an earthquake by creating vibrations that radiate through the Earth's crust. We'll put aside the issue that any such vibrations would be powerfully obvious to those working at the LHC. Earthquakes generally only occur at points between the tectonic plates. The LHC is in the Eurasian plate, and a good 900 miles from the nearest edge (which is somewhere near the heel of the Italy boot). If it was causing earthquakes, they would be expected to occur along the edge of the Eurasian plate. But the two recent earthquakes happened along the edges of the Carribbean and South American plates, which are nowhere near the Eurasian plate. In short, there's absolutely no reason to think that the LHC has anything to do with those quakes.
posted by dephlogisticated at 8:35 PM on April 3, 2010


Appreciate the patience and kindness extended through the time taken to answer these questions. A virtual hug to you all. Thank you.
posted by srbrunson at 2:32 PM on April 4, 2010


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