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Large Hadron Collider Question

INRM

Philosopher
Joined
Jul 24, 2002
Messages
5,505
At the penalty of sounding retarded... How do scientists know surely enough that Large Hadron Collider won't create a black-hole that will cause the whole earth to collapse into it?

I know they said the same thing with another particle accelerator... but this one is significantly more powerful and they even plan to see "micro-black" holes, I've heard...

INRM
 
At the penalty of sounding retarded... How do scientists know surely enough that Large Hadron Collider won't create a black-hole that will cause the whole earth to collapse into it?

Because the kind of collisions they'll be creating were quite common during the early stages of the universe. If creating stable black holes was a likely result, we'd have a whole lot more black holes and a whole lot less normal matter running around.
 
Because the kind of collisions they'll be creating were quite common during the early stages of the universe. If creating stable black holes was a likely result, we'd have a whole lot more black holes and a whole lot less normal matter running around.
Gee I was hoping for a more comforting answer!

As an extreme non-expert, how do we know there is not "a whole lot more" black holes? Aren't we looking for exactly what dark matter and dark energy are? Could not black holes account for the missing dark matter and energy?
 
Gee I was hoping for a more comforting answer!

As an extreme non-expert, how do we know there is not "a whole lot more" black holes?

Because black holes, even small black holes, aren't actually invisible. They scatter light that gets near them (gravitational lensing). So they aren't good candidates for dark matter (and they're massive so they can't be dark energy).
 
Thanks. I do remember reading a book (by Paul Davies? I can't remember) which nominated small black holes as the source of dark matter, but this was a few years ago.
 
Because black holes, even small black holes, aren't actually invisible. They scatter light that gets near them (gravitational lensing). So they aren't good candidates for dark matter (and they're massive so they can't be dark energy).


Well, not all black holes are (or have to be) massive. There well could be trillions and trillions of micro black holes that permeate the universe. We just don't know.


Cheers,
DrZ
 
Well, not all black holes are (or have to be) massive. There well could be trillions and trillions of micro black holes that permeate the universe. We just don't know.


Cheers,
DrZ

So thats where my socks go :p
 
Because the kind of collisions they'll be creating were quite common during the early stages of the universe. If creating stable black holes was a likely result, we'd have a whole lot more black holes and a whole lot less normal matter running around.

A better answer is that there are cosmic rays (protons with extremely high energy - higher than will be attainable at the LHC) bombarding the earth's atmosphere all the time. If high energy proton-proton collisions could create dangerous black holes it would have happened long ago from that.
 
Sol Invictus,

Weren't there some very massive black-holes that were created from the universe forming? And how much mass would the "micro singularities" created in the LHC be? And how much would be necessary to swallow up the whole earth... and how certain are we that mass is accurate?

I thought cosmic rays were energy, very low-wavelength, even lower than gamma-rays, not protons...


INRM
 
sol and zig are right on the money here. sol's point is probably a more convincing proof of the matter- INRM, the energies of some of the incoming cosmic ray protons are far higher than anything we're going to create with a particle accelerator on Earth. There are some of them that have been accelerated in the magnetic field of our galaxy- a "particle accelerator" 50,000 light years across, is probably the best way to put it without getting into too much detail. And others that emerge from some of the most energetic things we see out in the universe. I've stood and watched cosmic rays pass through 10 or 20 layers of 1-inch steel, at this exhibit at the Exploratorium in San Francisco.
 
Sol Invictus,

Weren't there some very massive black-holes that were created from the universe forming? And how much mass would the "micro singularities" created in the LHC be? And how much would be necessary to swallow up the whole earth... and how certain are we that mass is accurate?

I thought cosmic rays were energy, very low-wavelength, even lower than gamma-rays, not protons...


INRM

To start with, there is no such thing as lower wavelengths than gamma rays, gamma rays are the shortest wavelengths possible. Cosmic rays can be anything. Any particle coming to Earth from somewhere outside the Earth is a cosmic ray. Depending on your definition, particles from within the Solar System may not be counted, so the Solar wind won't count. Otherwise, everything is fair game. Photons from stars, hydrogen in the interstellar medium, electrons and protons from energetic reactions, even heavy elements from supernovae. They are all cosmic rays if they hit us.

At the moment, the energy of particles reaching us from things like supernovae are far, far higher than the energies we can create ourselves. If anything at all dangerous were going to happen, it would have happened long ago. Also, it would have happened all over the place, not just here.

Black holes were not created at the start of the universe. Early on, everything was simply far too hot for even atoms to form, let alone anything larger. Once things had cooled down a bit, matter could settle down into clumps, eventually forming stars, galaxies and so on. At the moment, we're not really sure exactly what came first. It could have been massive black holes which attracted other matter to form galaxies, or galaxies could have formed and then produced black holes at their centre (personally, I prefer the latter theory). What is certain is that massive black holes were not present in the early universe. Very small ones could have been present, but since they evaporate very quickly it is difficult to tell.

Finally, I'm not really sure how big a black hole would have to be to eat the Earth, and I don't know if anything more than a back of the envelope calculation has ever been done, since it isn't really something that anyone worries about. Basically, black holes emit energy (although whether that energy contains information is a different question). The smaller they are, the faster they emit it, so large, star sized hole last for billions of years, but the tiny kind that could be produced by particle collisions last fractions of a nanosecond. In order to be a danger to Earth, a black hole would have to consume matter faster than it evaporated. Once this process started, it would accelerate since a larger hole would evaporate slower but consume mass faster. While I really don't know how big it would need to be for this to happen, I do know that it is much bigger than anything we can currently manage.

One thing worth bearing in mind is that the LHC will initially collide particles with a centre of mass energy of about 1TeV (1,000,000,000,000 electron-volts), although it will eventually reach 14TeV. The Tevatron has been running since 1983. It collides particles with CoM energy of 1.96TeV. As far as I can tell, the Earth is still here.
 
The mass of a black hole potentially produced at the LHC would be in the range 1-14 TeV/c^2 (physicists often drop the /c^2 and give mass in units of energy). That is about the mass of a few to a few dozen sugar molecules or 20-300 CO2 molecules (a proton or neutron is about 0.001 TeV).


There are several reasons why the creation of black holes at the LHC would not be a problem:

1) The various models that suggest black holes can be created at the LHC also typically allow black holes to decay or evaporate, disappearing in a very tiny explosion of particles. The speed at which such a small black hole evaporates is incredibly fast: less than 1/10^80 seconds. That is not enough time for any other particles (such as nearby atoms) to be absorbed by the black hole, making it grow.

2) Even if the black holes cannot decay (which is an unlikely scenario), the black holes will likely be travelling so fast that they escape from the Earth. Remember, the particles at the LHC are being collided at nearly the speed of light, or 300,000 km/s. The probability of a black hole being produced in the collision with a speed of less than 10 km/s (the speed necessary to remain bound to the Earth) is very low.

3) The mass and size of the black hole is still very tiny. The gravitational pull on any nearby atom is going to be negligibly small compared to all the electromagnetic interactions between those nearby atoms. Any collision of an atom with the black hole (which results in the atom being absorbed) would be simply due to random motion, not due to being "sucked" in by gravity. And since the black hole is tiny, random collisions are very unlikely.

4) If black holes can be made by colliding particles together at energies of 14 TeV, then they would be produced in massive quantities in the universe in such things as supernovae. As noted by sol invictus and others, cosmic rays would also be producing these things on Earth right now (but those would be travelling too fast to stay in Earth's gravitational well and would escape into space). If these black holes do not evaporate, then there would be many of these things passing through space, with several of them passing through you each second (just like neutrinos). If black holes are going to be produced at the LHC, do not evaporate, and will grow rapidly (eventually eating all of the Earth) such as the "doomsday" scenario some people imagine, then the Earth really should have turned into a black hole long ago.


I should really stress that classical theories do not predict black holes to be produced at the LHC. The only models that allow black holes to be created in this case are ones with extra dimensions, such as string theory, and even then only when certain conditions apply. Very few physicists expect black holes to actually be produced at the LHC.
 
Professor Dr. Otto E. Roessler is Concerned

CERNs web site states that we have not been destroyed by effects of cosmic rays and micro black holes will evaporate.

However, cosmic rays travel too fast to be captured by Earths gravity, and Hawking Radiation is disputed and contradicts Einsteins highly successful relativity theory. Collider particles smash head on like a car collision and can be captured by Earths gravity, and relativity predicts micro black holes will not decay (Hawking called Einstein doubly wrong, yet it is Einstein who is repeatedly found to have been correct in his theories). There is currently no reasonable proof of LHC safety, LSAG (LHC Safety Assessment Group) has been trying for months to prove safety without success. I hold the minority opinion that it may not be possible because it may in fact not be safe.

Cosmic Rays from the legal complaint.

any such novel particle created in nature by cosmic ray impacts would be left with a velocity at nearly the speed of light, relative to earth. At such speeds, . . . , is believed by most theorists to simply pass harmlessly through our planet with nary an impact, safely exiting on the other side. . . . Conversely, any such novel particle that might be created at the LHC would be at slow speed relative to earth, a goodly percentage would then be captured by earths gravity, and could possibly grow larger [accrete matter] with disastrous consequences of the earth turning into a large black hole.

Professor Dr. Otto E. Roessler estimates 50 months Earth accretion time from a single micro black hole captured by Earth's gravity (translation at from German at lhcconcerns.com)

If this thing is so safe, why arent CERN scientists allowed to express any personal fears they might have about this Collider?

Alleged in the legal action: Chief Scientific Officer, Mr. Engelen passed an internal memorandum to workers at CERN, asking them, regardless of personal opinion, to affirm in all interviews that there were no risks involved in the experiments, changing the previous assertion of minimal risk.

(Statisticians generally consider minimal risk as 1-10%).

JTankers
LHCConcerns.com
 
At the penalty of sounding retarded... How do scientists know surely enough that Large Hadron Collider won't create a black-hole that will cause the whole earth to collapse into it?

I know they said the same thing with another particle accelerator... but this one is significantly more powerful and they even plan to see "micro-black" holes, I've heard...

INRM


This is about the third or fourth thread on this topic where you've asked precisely the same question. And in each one of the other threads, knowledgeable physicists like Zig and Sol have addressed your questions repeatedly.

So here's my question: After having had your questions addressed many times already by experts on the subject, why do you continue to ask the "black-hole" question as if there's something to it? And why do you continue to ask the question as if nobody has addressed it?
 
This is about the third or fourth thread on this topic where you've asked precisely the same question. And in each one of the other threads, knowledgeable physicists like Zig and Sol have addressed your questions repeatedly.

So here's my question: After having had your questions addressed many times already by experts on the subject, why do you continue to ask the "black-hole" question as if there's something to it? And why do you continue to ask the question as if nobody has addressed it?

Seconded, you are starting to look like a troll INRM.
 
Well, in INRM's defence, the thread was started in Nov 2007, and bumped ('yesterday') by New Blood JTankers.
 
Well, in INRM's defence, the thread was started in Nov 2007, and bumped ('yesterday') by New Blood JTankers.

Good point, I had missed that, but despite ordering there have been quite a few INRM threads on what seems to be same topic.
 
I believe people keep asking because they don't really understand the question, let alone the problem. Sol Invictus gave the first concise real useful answer, so let's stick with that one. As far as black holes go, any size one would would absord any matter that was not traveling fast enough to avoid it. Meaning the Earth the Sun or anything else. The thing is that the two would have to be gravitationally bound, so that any black holes travelling quickly through the Earth would only just suck up as much mass as reached its event horizon. Last but definitely not least, there are no such things as mini black holes, nor will there ever likely be any.
 
Okay. The earth has been hit with cosmic-ray bursts that have exceeded the LHC's operating power-levels. As a result is unlikely to produce a black-hole.

BTW: The LHC of many things is going to be used studying micro-black-holes right? What will their research entail?
 

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