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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.
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).