Now that we know where the idea of antimatter came from, we can talk about how the stuff itself is created. In the early 1900s, Albert Einstein put forth the idea that energy and mass were somehow connected, which he summarized in his famous equation E=mc2. This is where we find antimatter. Matter and energy are one and the same, and it is possible to switch between the two forms. Einstein's formula tells us the energy present in the mass of a particle at rest. This energy gives the threshold for the creation of antimatter in a process known as pair production.
Pair Production
In pair production, a photon (the basic unit of light) interacts with a nucleus. During this interaction, if the photon has energy equal to at least twice the rest of an elementary particle, such as protons and electrons, it will produce a pair of particles. This pair will consist of the elementary particle and its antimatter equivalent. For the production of an electron-positron pair, a photon would need to have around 1.6x1013 Joules. This may not seem like much, but it would require light at a frequency of 2.5x1020 Hertz. As a point of reference, visible light has a frequency in the range of 400x1014 to 800x1014 hertz. We need approximately one million times that energy to cause the phenomenon of pair production.
With energy requirements this high, antimatter production is quite difficult. However, laboratories in California recently managed to build a laser that could produce 10 billion positrons by firing at gold nuclei. While this is an impressive stride, a kilogram of antimatter would require a billion trillion times as much.
Check out the animation below for a demonstration of pair production
Animation created by Dr. Joe McCullough, Cabrillo College. Copyright 2004.3
Interacting With Antimatter
Pair production also occurs in a reverse process called annihilation. When a particle and its antiparticle collide, they annihilate, releasing all of the mass contained within them as energy. The formula E=mc2 returns to play here. This formula gives the energy released by this process. For even a single kilogram of combined matter and antimatter, the energy produced is exceptional, measuring a thousand times more than the energy from a kilogram of uranium in a fission reactor.
