Antimatter: everything you'll never be

If any of you are familiar with Dan Brown’s book Angels and Demons, or if you've been around any physics anything in the past few years, then you might know a little bit about something called antimatter. You get one thing, grab its natural opposite, smash them together, and things explode. But really, what is antimatter? How does that even happen? Well, I'm glad you asked.

As common in almost all of the most interesting physics concepts, the science was predicted before it was discovered. It was no different with antimatter. In 1928, Paul Dirac published a paper outlining the connections between Albert Einstein’s Theory of Relativity, which worked on a large scale, and Erwin Schrodinger’s equation of quantum physics, which worked on a small scale. Now, understand: Dirac was freakin’ brilliant. His mathematics was spot-on, and his explanation connecting these two branches of physics made perfect sense if one analyzed his equations. 

Perfect Sense.

However, this perfect math implied something strange. Given the setup of the equation, both an electron and a similar particle of opposite charge could be used as solutions. This further implied that every particle, not just electrons, had its own natural opposite, an 'antiparticle'. With this revelation, the task now was to prove that Dirac’s theorized ‘antimatter’ particles actually existed. 

Lucky for us, things started happening quickly in the world of quantum physics. Jump four years, to 1932: Carl David Anderson was playing around in his cloud chamber, shooting radioactive gamma rays through a lead plate, when he noticed that the electrons that were supposed to be traveling the same way (due to their similar charge) were actually going in opposite directions. After a bit of investigation, Anderson concluded that he had just saw anti-electrons, or positrons, in action, being split off from their counterparts through the gamma ray's energy. Just as Dirac predicted, quantum mechanics really did allow for two oppositely-charged particles of the same mass to exist. Moreover, when these two particles touched, they destroyed one another in a burst of energy. Interestingly enough, this explosion could be predicted by Einstein’s most famous equation, E = mc². Basically, Einstein stated that all matter is just super-condensed energy, the precise parameters of which were given in the equation. Therefore, when an electron and anti-electron touch, each releases exactly 511 keV worth of energy, the equivalent of their charge. The bigger the particle, the bigger the blast. 

A classic matter-antimatter interaction.

Later on in the ‘50s, the antiproton was found using similar methods. These discoveries opened the door to a whole new world of science. As experiments developed, scientists found that matter-antimatter pairs were fairly common, being produced every time enough energy hit a particle. We now know that this type of decay happens all the time in Earth’s atmosphere, where cosmic rays hit everything in sight. Regardless, it was still hard to study something that was instantly annihilated the moment it was produced. Real research couldn’t be conducted until magnetic chambers were developed that were strong enough to hold a positron, antiproton, or other antiparticle for a long period of time. Once this was achieved, scientists were able to delve into antiparticles wholeheartedly. 

Even so, keeping around a whole atom of antimatter is tough; atoms are electrically neutral, and so they cannot be kept in magnetic chambers under normal conditions the same way their smaller parts can. Yet scientists circumvented this issue by doing something quite clever: super-chilling the atom. An anti-hydrogen atom created in near-absolute-zero temperatures actually demonstrated weak magnetic properties. In this way, the atom could be captured and successfully controlled. As the process was refined, the duration of capture went from a couple of milliseconds to a full 16 minutes, completed just last month. With these leaps and bounds being made in the field, science could be on the verge of some huge discoveries about a side of the universe we know next to nothing about. 

Small differences in the properties of matter and antimatter, like their makeup and interactions with one another, have enabled us to recreate the beginning of the universe, find amazing properties about our own galaxy, and predict what might still be undiscovered in the universe. Even more, we might one day be able to solve the great mystery of why we ourselves are not made of antimatter right now. What happened in the beginnings of this universe to make the distribution so lopsided? How is there so much of one, and not the other? Are there antimatter galaxies after all? 

Yeah, I know; physics just blew your mind. That’s why I’m here. 

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Discussion questions: 

1. How many Nobel Prize winners are mentioned in this article? Hint: Dan Brown did not win a Nobel.

2. Wouldn't an antimatter spaceship be awesome? No, seriously, dude. Dude.