What is the Higgs boson & what does its discovery mean?

It's not often you meet someone who you can describe as "in the running for a Nobel prize". But I did this morning at the Methodist Central Hall opposite Westminster Abbey.

Someone with a sense of irony had chosen it as a venue for UK scientists to meet and watch, via the wonder of the internet, experimenters at CERN announcing that they had discovered a new sub-atomic particle which was probably the Higgs boson - an elusive particle that's evaded their knowledge for 50 years.

The man was Professor Tom Kibble, one of six scientists who predicted back in the 1960s that the Higgs boson should exist. He's now a slightly frail 79-year-old but obviously glowing inside with pleasure that his prediction was coming true. And he surely must be a candidate for the top scientific prize.

At CERN, they were announcing that their results in the past two years from two experiments driven by the Large Hadron Collider had uncovered a new particle. Physicists love to put numbers on things - and in this case they said their findings were "5 sigma".

That means there's only a one in three million chance that they're wrong. They're being a bit more cautious about calling their new particle the Higgs boson. They'll only say that its "consistent" with the Higgs boson.

But as one physicist from the rival Fermilab in the US said: "If it looks like a duck and walks like a duck, it is a duck"

So what's a Higgs boson? Let me take you back....Way back. The 'Big Bang' happens. Stuff is flying around at the speed of light - particles of all kinds with no time to get to know each other. A trillionth of a second after the Big Bang, the Higgs field is switched on - its a bit like putting ping-pong balls on a tray of sand. It slows the particles down. They get to cuddle up and form matter - the stuff we're made of. The Higgs particles give matter mass.

That's how the physicists see it. But for you and me, what does it all mean? Well, when they first discovered the electron in 1896, they didn't think it would be much use in practical life. I have a mobile phone in my pocket. I'm typing this on a computer. I've been watching what's happening at CERN on a TV monitor. All this depends on electrons. Who knows what might emerge from the discovery of the Higgs Boson?