Antimatter

Antimatter is material composed of antiparticles. Every particle, has a corresponding antiparticle. Antiparticles have the same mass as their corresponding particle partners, however, an opposite electric charge. An example of a particle and an antiparticle would be the electron and the anti-electron (commonly referred to as the positron). The electron has an electric charge of -1, thus, the positron, will have an electric charge of 1. However, a particle, such as the photon, that does not carry electric charge, or has 0 electric charge, will be it’s own antiparticle. Another thing to note about particle-antiparticle pairs, is that, when they come into contact, they can annihilate. Both particles will disappear in a flash of energy. In the case of the electron and positron, they will collide, and produce two photons. In addition, antihydrogen atoms can be formed, by means of a positron, orbiting an antiproton.

An unsolved problem in particle physics and cosmology, is also, why, at the formation of matter at the instant of the Big Bang, did the universe consist of almost entirely matter, as opposed to antimatter. This problem is known as baryon asymmetry: the imbalance of ordinary matter (baryonic matter), with anti-baryonic matter. The Big Bang should have produced both in an equal amount and the Standard Model of particle physics cannot account for why this is the case. There is no definite explanation at the present moment.

The modern idea of antimatter began with Paul Dirac, in his formulation of the his famous Dirac equation, in 1928, an attempt at a relativistic approach at the quantum theory. Out of the equations emerged the prediction of anti-electrons. Dirac, was attempting to reconcile special relativity with quantum mechanics, by showing how an electron could move at a relativistic velocity. The equation, however, has two solutions, one for the electron, and one for the positron. Thus, antimatter, was theoretically possible. However, Dirac himself, did not use the term “antimatter”. This prediction will be confirmed in 1932, when Carl D. Anderson, discovers the positron.

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