And Nothing Else (Anti-)Matters

Passionately CuriousAntimatter“And now, puny generic sci-fi superhero, I shall charge up my hyper-flux-capacitated antimatter bomb, and annihilate your entire planet! Lawrence, cue the evil-laugh tape!”

Anti-matter (or, alternatively) antimatter is an age-old favorite power source among writers of scifi and superhero comics alike, which is probably why most people you’ll talk with will at least admit to having heard of it. It helps that Dan Brown also used an antimatter weapon as a main plot point in Angels and Demons (2003), which was turned into a fairly successful motion picture in 2009. However, while most people at least have some sense that it exists (which certainly is an accomplishment in and of itself), relatively few people have any clue as to the essence of the thing. Today, I’ll be taking a short foray into the ins and outs of antimatter, showing you what it is – and what it is not.

First and foremost, everything you see around you is composed of ‘normal’ matter1 – which is at the very smallest level built from ordinary protons, neutrons, and electrons2. However, for each of these, there exists an evil twin! That’s what antimatter really is: they’re ‘opposite’ particles. As such, most relevantly, there exist anti-protons, anti-neutrons, and anti-electrons (which we call positrons). These particles all have the exact same mass, but their charges are opposite: where protons have a charge of +e3 and electrons have a charge of –e, anti-protons carry a charge of –e and positrons carry a charge of +e. As opposite charges attract, this means protons are attracted to electrons the same way they are attracted to anti-electrons.

Of course, that’s not the most interesting bit. You see, something very interesting happens when a bit of matter meets a bit of antimatter: they annihilate each other, turning the entirety of their mass into a giant burst of energy! How much energy is generated in this process is dictated by Einstein’s famous E = mc2, as the entire mass of both is converted into pure energy. For comparison’s sake, you would only need a blob of antimatter weighing as much as a single grain of rice to release as much energy as the bombs that leveled Hiroshima and Nagasaki.

This is also the reason that everything we see is only made up of normal matter: at the time of the Big Bang, somehow more matter was created than antimatter4. After this, in our (at this point in time) still very tiny universe, every time a bit of antimatter met a bit of normal matter both were annihilated, until the less plentiful antimatter was completely depleted.

However, we humans are a clever bunch: we’ve managed to create such high-energy reactions that we’re very capable of creating anti-matter in a lab, for example at the CERN particle accelerator in Geneva.

“But,” I hear you asking, “isn’t that super duper dangerous? Isn’t that the whole thing that happens in Dan Browns book, where they stole the supply of antimatter and tried to blow up the Vatican?”

No, no, no! There is absolutely zero need to worry about antimatter terrorist attacks, trust me. First and foremost, it’s incredibly difficult to isolate any antimatter whatsoever. The bits that are made in particle physics laboratories around the world tend to zip away the instant they are made, because of a very simple reason: everything around you will cause them to explode! In what kind of container would you keep an antimatter bomb of any respectable size? Surely, a container made from ordinary matter would be rather problematic: the instant the contents touch the sides, the entire thing (and your lab/town/country/planet) is blown to smithereens. There’s the option of putting the stuff in a strong magnetic fields, but our technology is currently not advanced enough to allow for the transportation of antimatter. In addition, this is the reason why particle physicists don’t just have bottles of antimatter lying around to be stolen in the first place, so I really wouldn’t worry too much about it. In fact, ordinary bombs, sadly enough, are much, much cheaper to produce, and have proven perfectly capable of leveling places as is.

And now you know all that you need to know about antimatter, really. There’s lots of fascinating theory behind it all: the model of the Dirac Sea, first dreamt up by Paul Dirac, for example, which predicted antimatter should exist for the (then current) understanding of physics to be correct. There’s also the ramifications of the existence of antimatter in the context of the whole of particle physics to consider. But these tend to delve rather too deeply into the nitty gritty particle physics theory and formulae. For now, know that you know a good bit more about antimatter than you did yesterday.

Sadly, this will (at least for now) be the last article I write as editor for Writer’s Block. I hope to still be bringing you all some science-y fun occasionally in the months to come though – I’ve still got a series on quantum physics just begging me to write it 😉

See you all again soon, and remember to stay curious!

Paul

Footnotes

1. And a good thing too, as we’ll see in a little bit.

2. These three particles make up the vast, vast majority of ‘stuff’ around us. There are other particles, but they’re much rarer to be observed in nature. Maybe I’ll ever get around to writing an entry in this series about quarks, which are in turn the building blocks of protons and neutrons, but until then, hopefully this Wikipedia article can tide you over somewhat.

3. e is what physicists call the ‘elementary charge’: this is amount of charge carried by a single proton or positron. Electrons and anti-protons carry –e: the same charge, but with opposite sign.

4. Why this happened is still an open question in physics, though much work has been done over the past few decades in an effort to solve this mystery. If you’re interested, you could try this article, for example.

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