Antimatter particles are sub-atomic particles with properties opposite those of normal matter particles. For example, a positron is the antiparticle equivalent of the electron and has a positive charge. When a particle and its antiparticle meet, they annihilate, releasing massive amounts of energy, according to Einstein's famous equation E=mc^2, where E is equal to energy, m is equal to mass, and c is the speed of light.

Antimatter particles are created in ultra high-speed collisions. In the first moments after the Big Bang, only energy existed. As the universe cooled and expanded, particles of both matter and antimatter were produced in equal amounts.