What is CERN up to now?

Physicist Francesca Chadha-Day answers...

Chris - And didn't they have a weasel problem? They did, didn't they?

Fran - Yes, they did. CERN is the home of the Large Hadron Collider, which is a machine designed to smash protons and sometimes other things together very quickly so we can see what comes off. In 2012 they discovered the Higgs Boson, the particle that gives things mass. That was a very big deal. In 2016 they had a problem where a weasel got into their electrical equipment, which was quite amusing, but dealt with very quickly.

Chris - How did it get in and what did it do?

Fran - So CERN is a very, very large facility and for that reason it has to be in the countryside. So, wild animals just are a bit of a problem. So it was an external box of electrical stuff and it got in, it chewed through some wires, there was a short circuit. I don't think the weasel made it

Chris - It's quite funny that you've got something that's worth 3 billion Euros, that's running with its own power station running it, and a weasel got into the works and just brought the house down.

Fran - Yeah. They did get it up and running fairly quickly.

Chris - Have they got a weasel detector or something? How did they find out that that's what did it?

Fran - I think they probably found the body of the weasel.

Chris - Oh dear. So it didn't end well for the weasel. So what are CERN actually doing now then? You said they found the Higgs Boson and they've done confirmatory experiments to be reasonably sure, and then Peter Higgs was one of the co-winners of the Nobel prize to reflect that. What are they doing now?

Fran - So since then they've been searching for other new particles and haven't found any, but the knowledge that there aren't new particles in the range in which they've been searching is actually quite valuable, and actually rules out a lot of theories of new physics that we thought might be true.

Chris - So sometimes a negative is as valuable as a positive finding?

Fran - Yeah, it's obviously less exciting but it does mean that physicists are starting to rethink things like what we think dark matter could be, what new particles could be out there. I'd also like to mention that CERN isn't only the home of the Large Hadron Collider. That's perhaps the most famous experiment at CERN, but there's actually a lot of smaller experiments there. For example, a lot of experiments looking at nuclear physics and nuclear decays, other experiments searching for dark matter. So there's a lot going on.