Particle accelerator

You may have heard that it's about time to fire up the Large Hadron Collider (LHC). If you haven't I should explain that the LHC is the world's largest particle accelerator. It's purpose is to zing subatomic particles around in a huge underground circle until they reach nearly the speed of light and then smash them together. This causes them to break down into smaller particles that haven't existed outside of a laboratory since a few seconds after the Big Bang.

There's been some controversy about this. Some people with very litte idea what they're talking about have claimed that this machine could generate black hole matter and consume the Earth.

Let me explain to you what a Black Hole is.

You start with a star. A really BIG star. See that one outside your window? The one that blocks out all other stars? You might call it The Sun. It's huge. It would take more than 100 Earths strung together like pearls to reach from one side to the other. It's not nearly big enough. It's only a medium sized star.

So, once you have a truly massive star you have to sit around and wait for it to die. For a star that big it shouldn't take long. The big ones burn out and die faster than the smaller ones. A few hundred million years should do the trick. First it'll get bigger and then it'll collapse. Then it'll collapse some more. Then it'll keep collapsing until the individual atoms that make up this dying star get crushed under the weight. The whole thing gets pressed down to the size of a couple of pixels.

Anything with enough mass to crush itself that small is also massive [def. massive: containing lots of mass] enough to pull in light. Light and most anything else that gets too close. Earth would be just a tasty treat. That's a black hole. If it doesn't have enough pull to keep light from escaping then it's not a black hole and will fall apart.

To put it another way, if you took the entire Solar System and put it all together it wouldn't be enough mass to form a black hole.

So, back in the lab, by some highly improbable fluke the two particles slam into each other but don't break into pieces but form a super dense particle like might be expected in a black hole. It would evaporate immediately. On the off chance that it doesn't evaporate immediately - which is so unlikely as to be definite proof of the existance of God - it would be a black hole with the overwhelming gravitational pull of two whole electrons.

So just don't worry about it. The only thing to concern yourself with is the best way to mock the people who are worried about it should you meet them on the street.

see also:http://www.guardian.co.uk/science/2008/jun/30/cern.particle.physics2