What happens when matter and antimatter collide?
Great question.
![simulated data modeled for the CMS particle detector on the Large Hadron Collider](https://www.ucl.ac.uk/culture-online/sites/culture_online/files/styles/large_image/public/case-study/matter.jpg?itok=ema7Ms5b)
10 March 2022
Matter and antimatter are collections of particles which form particle pairs with the same mass but opposite electric charge. For example, an electron (negative charge) and a positron (positive charge), or a proton (positive) and an antiproton (negative).
When matter and antimatter collide, the particles destroy each other, with a huge energy release. Depending on the colliding particles, not only is there a great energy release, but new, different particles may also be produced (such as neutrinos and various flavours of quark – see figure below). These new particles will have a lower mass than those in the original collision, due to the law of conservation of energy and Einstein’s very famous equation E=mc2 – some of the energy goes into heat and light, some into forming the new particles.
Antimatter is all around us – for example bananas emit antimatter. This is because they contain a particular type of potassium (called potassium-40) which undergoes radioactive decay releasing a positron every 75 minutes. But this positron is very quickly annihilated by a passing electron.
In fact, trying to artificially make and keep antimatter is a difficult and expensive business. Particle accelerators, like the Large Hadron Collider at CERN in Geneva, smash particles together in order to create antimatter – but it costs billions of pounds to make tiny amounts which are very difficult to keep for any length of time because they are quickly destroyed in a collision with their matter counterpart.
In the same way particles make up matter such as chemical elements – for example, hydrogen is composed of a proton and an electron – antiparticles make up antimatter – so a positron and antiproton make antihydrogen. In principle it is possible to have anti-anything - antihelium, antioxygen, anticarbon, antielephant, antiearth. We live in a predominantly matter universe. But who knows what secrets a hypothetical antiuniverse might hold and what a collision between an elephant and an antielephant would produce!
![Antimatter collision](https://www.ucl.ac.uk/culture-online/sites/culture_online/files/styles/medium_image/public/antimatter.jpg?itok=xEY6xzMd)
https://astronomy.com/magazine/ask-astro/2012/01/collisions-happen
https://www.symmetrymagazine.org/article/april-2015/ten-things-you-might...
https://newatlas.com/physics/what-is-antimatter-explainer-primer/