Weird Matter, Part 2: Antimatter
Welcome to part two of the Weird Matter series, where we are exploring the strange substances that make up our universe. In part-one, we talked about dark matter and dark energy. Today, we will talk about antimatter, something that is as real and important as it is fascinating.
What’s so “anti” about antimatter?
“Anti” is a word we use to show that we are against something. Someone who is opposed to drugs might say they are “anti-drugs.” Sometimes you might even announce that you are “anti-homework.” So, what is antimatter, and what is so “anti” about it?
Well, you might know that matter is made from particles like atoms and that atoms are made up of protons, neutrons, and electrons. Maybe even that protons and neutrons are made up of quarks. It turns out that each of these particles also has an opposite twin. Protons have antiprotons, neutrons have antineutrons, quarks have antiquarks, and electrons have positrons. These twins, including other twins of other particles, make up what we call antimatter, and they are basically the same as their normal matter siblings. But, there are a few really big differences between them – the most important being that they have opposite charges. So, for example, while an electron has a negative charge, its antimatter positron twin has a positive charge. You can think of antimatter almost as an “evil reflection” of normal matter.
In fact, the particles of antimatter can combine in all the same ways that normal matter can – you could make an antimatter computer, house, or even a planet. But there’s a reason why you never see these things… Whenever antimatter particles touch their normal matter twins, they explode!
Why the explosion?
Antimatter and matter explode when they encounter each other because their charges are opposite. When this happens, energy gets released in the form of gamma rays. Gamma rays are just a type of energy.
Where can I find antimatter?
Because antimatter and matter explode on contact, antimatter is extremely rare. But that doesn’t mean it’s never been seen before. In fact, some people see it all the time! All around the world, there are particle accelerators – giant machines that scientists use to smash particles into each other. When they do this, a lot of energy is crammed into a small space, which can create antimatter! Even though the antimatter particles only exist for less than a second, we can still study them. In fact, in 2010, some clever scientists found a way to trap antimatter in containers for 15 minutes!
Another cool fact – did you know that you actually release antimatter every day? When you eat, drink, and breathe, you naturally ingest this substance called potassium-40. When potassium-40 breaks down in your body, it releases positrons (the antimatter twins of electrons)! While the positrons do explode, there aren’t enough positrons released by potassium-40 to harm you in any way.
Why is antimatter so important?
Antimatter is a big subject in science because it can tell us a lot about our universe. When the universe did begin with the Big Bang 13.8 billion years ago, an equal amount of matter and antimatter should have formed, come into contact, and destroyed each other. But this clearly didn’t happen, because there’s normal matter all around us! So how did this happen? How did normal matter win? We think that answering this question can tell us some really important, fundamental things about our universe.
Antimatter is also extremely important in the medical field. Positron Emission Tomography scans, or PET scans, allow doctors to take precise images of the inside of your body and brain, which can show them whether everything is healthy or not. And as the name says, PET scans actually use positrons (the antimatter twins of electrons) to create these images! When certain radioactive substances are inserted into the body, they release positrons, and these positrons, as we mentioned earlier, release gamma rays when they die. The PET scanner detects these gamma rays, creating images of certain body parts. Antimatter matters!
