In particle physics, annihilation is the process that occurs when a subatomic particle collides with it’s antiparticle. Its antiparticle is a particle of the same mass but with opposite charge. The collision of a particle and its antiparticle produces other particles. In everyday speech, annihilation means to destroy, although in physics that description is not as accurate. Indeed, the two original particles disappear, but they produce other particles. The total energy of the reaction is conserved, meaning the energy contained in the original particles is maintained in the resulting particles.
What’s all this talk of particles? What kinds of particles?
The most common annihilation event on Earth occurs when an electron collides with its opposite, the positron. The electron is the negatively charged particle responsible for electricity and chemical reactions, and positron comes from natural decay of radioactive elements. When these two particles slam into each other, the produce photons, the particle responsible for light!