What does the new collider do, and can it make black holes?

A scientist observed a screen last week showing traces of the first protons injected in the Large Hadron Collider. (Fabrice Coffrini/Associated Press)

The Large Hadron Collider, switched on last week in an underground tunnel in Switzerland, is actually two particle accelerators fastened together to make a collider. One of them accelerates protons clockwise, and the other counterclockwise - and when the protons have enough energy, magnets are used to steer them into each other and a particle collision occurs.

This is no big deal. Nature does this sort of thing all the time. The difference here is that the proton-proton collisions take place in the laboratory so physicists get a chance to see what happens.

Last week, only part of the collider was turned on. Protons were controlled and accelerated around the entire machine (17 miles around) but no attempt was made to have any proton-proton collisions. That final step will be accomplished sometime before the end of October.

So, when the device starts colliding protons next month, will it then make black holes?

Absolutely not!

Curiously, even though black holes are assumed to exist by everyone, including some of our best scientists, black holes have never been proven to exist. Indeed, they are predicted by theories that we know are wrong.

Black hole candidates have been discovered by astronomers, but they are all super-massive objects many times the mass of our sun and we really don't know what they are. Microscopic black holes do not exist, except in the imagination.

I have a theoretical physicist friend who, tongue in cheek, says that when the Large Hadron Collider is fully up and running, the colliding protons will produce a tiny woman and a tiny antiwoman. Certainly he can make his theoretical calculations, and show that the probability, while tiny, is not zero. But we know that his prediction won't come to be. It is the same with black holes.

Physics is an experimental subject and we should all stop taking theoretical calculations seriously until they are confirmed by experiment.

Dr. Knowledge is written by physicists Stephen Reucroft and John Swain, both of Northeastern University. E-mail questions to drknowledge@globe.com or write Dr. Knowledge, c/o The Boston Globe, PO Box 55819, Boston, MA 02205-5819.