Particle physics – science doesn’t get much bigger or more exciting than this.
It involves the biggest, most complicated experiments in the history of science, with the fastest computers, the coldest temperatures and the strongest magnets on Earth.
Particle physics re-creates the universe just after the Big Bang and hopes to answer the questions that humans have been asking for eternity; “Where do we come from?” “What are we made of?”
So what exactly is particle physics? Find out, from atoms and particles to accelerators and detectors in our introductory pages.
You can link direct to the biggest particle physics experiments around the world and visit our news section to see what goes on in particle physics in the UK and worldwide.
Atoms and Particles
So what is particle physics?
Particle physics is a journey into the heart of matter.
Everything in the universe, from stars and planets, to you and the chair that you're sitting on, is made from the same basic building blocks - particles of matter.
Some particles were last seen only billionths of a second after the Big Bang. Others form most of the matter around us today.
Particle physics studies these very small building block particles and works out how they interact to make the universe look and behave the way it does.
We see that atoms consist of a nucleus, ten thousand times smaller than the atom, surrounded by a cloud of electrons. The nucleus is a collection of particles called protons and neutrons. And inside protons and neutrons we find particles called quarks. Quarks are so small that we haven't yet been able to measure how big they are - we just know that they are at least ten thousand times smaller than the nucleus. They are so small that we treat them like mathematical pinpoints in our theories.
Zooming down in scale from a person to a fundamental particle like a quark or an electron is like shrinking the diameter of the whole earth to the size of a 5p coin. And then shrinking the 5p by the same amount again. This is what we mean by really small.
How do we do particle physics?
We recreate the conditions just after the Big Bang, when particles roamed freely through the Universe. We do this with powerful particle accelerators which accelerate particles close to the speed of light and smash them together. Particle physicists then look at what happens in the high energy collisions.
Particle physics is a bit like trying to find out how a watch works by bashing together two very expensive Swiss watches and then learning to rebuild them from all the bits of glass, cogs and springs. In place of Swiss watches we use particles so small that you could fit about ten thousand million of them across a watch face, and despite their tiny size, the collisions between these particles have as much energy as a large aeroplane taking off!