Antimatter, Y'all

When I was a kid, few words conjured up the fantastical better than antimatter. The idea seemed fanciful: for every type of matter, there was an evil twin with the opposite electrical charge, and if the two came into contact, there would be terrible destructive consequences.

This concept was prevalent in comic books, science fiction novels and TV shows, and even mainstream movies during my youth. Antimatter was presented as unbelievably exotic, and unimaginably dangerous. Typically, some evil supervillain would get their hands on some antimatter, and the threat of incredible destruction forced the superhero to intervene.

Imagine my joy when, as a slightly less young kid, I discovered that antimatter was very real.

Let me try my best to explain what it really is. The description I gave above actually isn’t too far off from the reality. It’s accurate to say that every charged particle has an antimatter particle with the opposite charge, and it’s also true that contact with a particle of the opposite charge would produce a lot of energy.

In addition to charge, there may be other more subtle differences related to the weak force and gravity, but I’m going to focus on the charge for now.

Charge, you say? What on earth does that mean? What even is a charge?

At its core, charge is a fundamental property of matter, just like mass. That means we can’t explain what it is in terms of anything else. These are called axioms in physics and mathematics: things that are self-evidently true all the time, but which can’t be proved or explained any further.

We say that electrons have a negative charge and protons have an equal, but opposite positive charge. This means that electrons push one another away with the same force that protons push one another away, and it also means they attract to the same extent that protons attract one another.

There’s not really anything inherently negative about the charge electrons have, nor is there anything positive about protons, but ever since Ben Franklin called one charge negative and one charge positive, the convention has proven to be useful enough.

Protons and electrons are very, very different in another notable way, too: their mass. A proton weighs roughly 2000 times more than an electron. However, there is a particle that seems to be the same size as the electron that is exactly opposite in charge.

This particle should probably be called a positron, but instead the name anti-electron has stuck. Oh, physicists!

Even still, the name anti-electron conveys everything you need to know: it’s just like the electron, but with the opposite charge. If an electron and an anti-electron touch one another, they really do annihilate one another instantaneously, and there’s a lot of energy released.

Thanks to Einstein’s famous equation E=MC², we know that all of the rest energy of both particles is turned into gamma rays, creating an incredible burst of energy. As far as we know, there is no more efficient mechanism for producing energy in the universe.

So, why don’t we have antimatter guns capable of greater destruction and more precision than nukes? How come there aren’t antimatter-powered flying cars and power plants?

Well, it turns out that antimatter is hard to come by. During the Big Bang, it seems as though roughly equal amounts of matter and antimatter were created, but that word roughly is very important here. For every billion parts of antimatter, there were a billion and one parts of regular matter. It was immediately after this moment that the two types of matter created a photon swarm that took hundreds of thousands of years to clear out.

That tiny bit of leftover mater—the one extra part per billion—is everything in the universe we can see. The rest of the matter has been annihilated, turned into unimaginable amounts of energy.

The good news is that we can manufacture the stuff! The bad news is that producing a gram of antimatter would take more energy than the entire planet uses in a year. In fact, if you put it all together, a gram is much, much more antimatter than we’ve ever produced.

Now imagine trying to store the stuff, and remember that any contact with ordinary matter is going to result in a catastrophic explosion. Magnetic fields can be used to contain tiny amounts today, but doing this at any kind of scale is tough to imagine, given our understanding of physics today.

So, no, we probably won’t be filling our cars up with antimatter any time soon, but it’s intriguing to know that there’s an ultra-efficient way to unlock energy from matter, and you can bet that we’re going to do everything we can to figure out if we can use it one day.

And here’s where science fiction jumps in! I remember how the sci-fi media of my youth slowly educated me as to the wonders of the universe, and antimatter was at the top of the list of cool phenomena. If not for sci-fi, including comic books and TV shows, I’m not sure I would have become this curious about things.

Science fiction today speculates about how antimatter might one day fuel great voyages across the cosmos, harnessing the most efficient way to produce energy. Great technology is indistinguishable from magic, and writers have often fantasized about antimatter.

If you’re a writer here on Substack and you’ve written about antimatter, let me know in the comments! If you’re a fan of sci-fi, you might consider joining this conversation over on Notes where we talk about different science fiction topics every week. As usual, curiosity is the key to understanding. Join in and let’s have a little fun!