Colliding Particles Can Make Black Holes After All

cremeglace writes with this excerpt from ScienceNOW: "You've heard the controversy. Particle physicists predict the world's new highest-energy atom smasher, the Large Hadron Collider (LHC) near Geneva, Switzerland, might create tiny black holes, which they say would be a fantastic discovery. Some doomsayers fear those black holes might gobble up the Earth — physicists say that's impossible — and have petitioned the United Nations to stop the $5.5 billion LHC. Curiously, though, nobody had ever shown that the prevailing theory of gravity, Einstein's theory of general relativity, actually predicts that a black hole can be made this way. Now a computer model shows conclusively for the first time that a particle collision really can make a black hole." That said, they estimate the required energy for creating a black hole this way to be roughly "a quintillion times higher than the LHC's maximum"; though if one of the theories requiring compact extra dimensions is true, the energy could be lower.

Re:Yes

[jandoedel]

a) a black hole created in a particle accelarator would evaporate too quickly to be dangerous
b) the energies that LHC is producing are a LOT smaller than the energies that a lot of cosmic rays have when they hit earth. it's a lot of energy for man, but not for nature, actually quite common. While you were reading this comment, a couple of particles with this energy PASSED THROUGHT YOU

c) don't panic

Re:The black holes are not dangerous

[jandoedel]

The mass will be the rest mass of both colliding particles + the kinetic energy they both have (a couple of TeV).
It won't even have the energy of a grain of salt. It will have the energy of about 1 helium atom.

Re:Yes

[Anonymous Coward]

Are you aware that the particles in the LHC are moving at ~= the speed of light?

Ignorance, plain and simple

[Judinous]

The Luddites that believe the LHC is going to destroy the Earth are really starting to get on my nerves. It is obvious even with a simplistic high-school level of understanding that any black holes formed by the LHC (if such a thing is even possible) are completely harmless. If we were to collide two protons with enough energy to produce a black hole, you would end up with (very temporarily) a black hole that has the mass (and thus gravitational pull) of two protons, with an electric charge of +2.

Let's take a look at a Helium atom. Helium nuclei are (usually) composed of two protons and two neutrons, thus they have roughly twice as much mass (and gravitational pull) as our aforementioned black hole. This nucleus also carries an electric charge of +2. That means that Helium nuclei exert more attractive force on their surroundings than the worst-case scenario black hole that can be produced by the LHC.

In the most extreme case, the closest that one of these miniature black holes would get to sucking in the matter around them would be to capture an electron or two into orbit around them in the same way as a Helium nuclei would, before the black hole evaporates. That would be quite an exciting, interesting, and completely harmless development.

Re:Ignorance, plain and simple

[stevelinton]

If we were to collide two protons with enough energy to produce a black hole, you would end up with (very temporarily) a black hole that has the mass (and thus gravitational pull) of two protons, with an electric charge of +2.
 

Not true, or at least not the way you mean. Each of the protons going into the collision carries its rest mass, but also the extra mass due to the fact it's moving at almost light-speed. In the case of the LHC this is about 10000 times greater, so you end up with a black hole with the mass of roughly 20002 protons (and, indeed charge +2).

Re:the infinity irony

[meta-monkey]

This did not any sense.

Which is why he accidentally the entire nobel prize.

Re:Yes

[Anonymous Coward]

The ~ is the important part. The collision needs to not be head-on by less than one part in a billion for the '~' not to imply escape velocity for something with proton mass. And this doesn't even depend on how you can't really produce a single non-interacting object from a p-p collision. So it wouldn't be at rest.

Second, there are things bigger than Earth (say, the Sun, or any other stars) which are being hit by a vastly larger number of cosmic rays. They are also thicker and denser -- for the vast rate of these interactions over their billion year history and the high target density after production, the black holes would have to be basically non-interacting for the Sun to exist. In which case there is no problem. Or they would have to not be produced. In which case there is still no problem.

A lot more than one He Atom

[Roger W Moore]

A helium atom has a mass of roughly 4 GeV/c2. The current lower limit on Black Holes at colliders is 1 TeV, or about 250 times more energy so it will have far, far more energy than a Helium atom.

Re:Not a Discovery

[evanbd]

It is a mathematical discovery about the properties of the equations that we think describe the particle behavior. Assuming their math was correct, it is a mathematical discovery like any other, but in a highly limited area (this specific set of equations). Whether it is a mathematical discovery that is also a description of physical reality depends on whether those equations actually describe particle behavior at those energy levels, which we don't yet know.