What’s the Matter, Antimatter?

Matter is what makes up all the stuff we can touch. In the standard model of particle physics, all matter is made of combinations of the twelve fundamental particles of matter. (Most matter is made up of just three: up quarks, down quarks, and electrons.)

Matter has properties like mass, charge, spin, and (in the case of quarks), colour charge.

But every matter particle has a mirror counterpart. These are the antimatter particles. (You might have heard of them in “antimatter drives” from sci fi.)

An antimatter particle has the same mass as its matter counterpart, but otherwise its properties are opposite, which leads to some exciting potential.

For instance, an electron has a mass of 0.0005 u, and a charge of -1 e. A positron — the anti-electron — has the same mass, but a charge of +1 e.

It’s easy to see what the opposite electric charge would be for an antimatter particle. Electrons and positrons don’t have colour charge… but what about those that do? What is the opposite of “blue”? Well, it’s antiblue, which seems to mean there are actually six options for colour charges: red, green, blue, antired, antigreen, and antiblue… but the first three only apply to matter quarks, and the second to antimatter quarks.

That’s not the fun part, though.

If an electron and a positron meet up, they annihilate each other.

Because they’re opposite particles, they cancel each other’s existence out, and create a blast of gamma radiation (if you can call two hugely energetic photons a “blast”…) This burst of energy is the scientific idea behind the sci fi antimatter drive.

If annihilation with matter isn’t enough, mathematically at least, antimatter can be taken as travelling backwards in time.

A Model Family: The Leptons

Bottom row, left to right: electron, muon and tauon.
Top row, left to right: electron neutrino, muon neutrino, tau neutrino.

In the standard model of particle physics, there are two families of particles that make up all matter. These are the quarks, which combine to make particles like protons and neutrons, and the leptons.

Leptons have charges of 0 or -1 e, so they can interact through electromagnetic forces. They also interact through the weak force. They do not have color charge, so they don’t interact through the strong force, which means that unlike quarks, they aren’t very good at joining up to create other particles.

What’s Going On Here?

Poster science is an experiment in turning science topics into quirky art.

The current topic is particle physics. This site gives a bit of background information on what these pictures are all about.

In Particle Physics:
Particle Physics?
A Particular Heirarchy
A Model Family: The Quarks
The Strong Force
Quantum Uncertainty
A Model Family: The Leptons
What’s the Matter, Antimatter?

Quantum Uncertainty

Werner Heisenberg

In the mid 1920’s, Werner Heisenberg worked out a mathematical description of quantum mechanics.

One new concept he introduced was the uncertainty principle. This is the surprising idea that it is impossible to know with absolute precision both the position and the momentum of a thing, or to know the exact energy of a thing at a certain time.

The Strong Force

Gluons make the strong nuclear force happen.

Many particles have electric charge. Electric charge comes in many sizes, but two types: positive and negative.

Some particles, like quarks, have another charge-like thing that comes in three types, called colour charge.

A Model Family: The Quarks

Particle physics uses something call the standard model, which describes the fundamental particles, and how they behave and interact.

It divides the fundamental particles into three families, the quarks, the leptons and the gauge bosons… and one loner, the Higgs Boson.

There are six different quarks, which get organised into three pairs because their properties follow a bit of a pattern.

A Particular Hierarchy

An atom is made of protons and neutrons, with electrons around the outside. Protons and neutrons are made of up and down quarks.

Particle physics basically deals with things that are smaller than atoms – that is, subatomic particles.

Many subatomic particles are made of smaller particles again. If you try to break a particle down into its constituent pieces, you eventually reach a particle that can’t be broken down further (as far as we know!) These basic units are called fundamental particles.

Particle Physics?

Two up quarks, one down quark, and a bunch of gluons… that’s a proton!

Particle physics is what they do at CERN. It’s why they built the Large Hadron Collider, that big experimental facility built underneath France and Switzerland that fired up a few years ago and managed not to destroy the whole world with a black hole.

The Large Hadron Collider remains the biggest, most complicated piece of science equipment ever made.

… Which seems almost ironic, as it’s made to study the tiniest, most basic pieces matter is made of.

That’s what particle physics is all about: the study of the bits of matter that are smaller than atoms. It’s a weird world down at the subatomic level. There are forces that act over such small distances that you can’t detect them on our scale, but which are absolutely crucial to keeping the fundamental building blocks of everything stuck together. There are things with silly names, like “strange quarks”, or “gluons”, and there are weird ideas, like colour charge, which doesn’t actually have anything to do with colour.

Are you ready for a trip down the rabbit hole into the world of particle physics?