Question: What is your machine you work with used for?

Kristian Harder answered on 14 Nov 2013:

Right now I work with the Large Hadron Collider at CERN in Switzerland and France. (It’s quite big and actually crossing the border between the two countries.) The purpose of that machine is fundamental research, or “blue skies research”, as some people call it. This means we use it without any specific application in mind, not to develop a product, not to solve a particular problem. Just to find out how things work. And in the case of the LHC, how the universe itself works. We use two beams of protons (basically hydrogen atoms without the electron), accelerate them to almost the speed of light and then make them hit each other head-on. This releases an enormous amount of energy, which then turns itself into new particles. Kind of like a miniature version of the Big Bang that our universe started with. And by looking at what happens in our mini-Big Bangs, we understand a lot more about the universe we live in. What matter is, what different types of matter there are (the elementary particles), what forces exist (such as electromagnetic interaction, gravity and so on) and how they work. Eventually, this knowledge will be applied for something useful, but that’s our job. We just get the knowledge that other people can use.

Oh, but it’s worth mentioning that some of the beams we create for our accelerators (LHC and others) are used for other purposes: cancer treatment, material analysis, extremely powerful x-ray applications and so on. So, even though we particle physicists are not involved in practical use of our machinery, other people do use our machinery for other areas of science and medicine. And the technology that we had to develop to build and operate our accelerators is spreading out and is having many practical applications as well. For example the superconducting magnets now used in medical imaging (MRI scanners, PET scanners), particle detectors used to secure ports by scanning freight containers for illegal nuclear material, the world wide web now used to run most of the economy – it’s all coming from particle physics and their machinery!