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Have you ever wondered what a person who is the exact opposite of you would look like? How would they be different or contrast from everything about you? If you were a particle, this would already be a reality! Every particle has an antiparticle, a subatomic particle with equal mass to the original particle, except it has an opposite electric charge or magnetic movement. For example, a particle like an electron has an antiparticle called the positron. The positron is just a positively charged electron and is also called the antielectron. Another example is the proton and the antiproton, the neutron and the antineutron, and so on. The main feature of antiparticles is their interactions with their original particle-selves through a process called annihilation to release energy. Annihilation, in physics, is defined by the collision and disappearance of a particle and its antiparticle to release energy. One of the most common annihilations occurs between the electron and its antiparticle, the positron. The two particles combine very briefly to form a quasi-atom called positronium. After that brief moment, the annihilation releases 2-3 gamma rays from the collision point. A quasi-atom is when two ions of opposite charge form a particle. This signifies that the annihilations between particles and antiparticles will collide and briefly form their combinations of quasi-atoms before the annihilation completes. There are different cases of particles and antiparticles, for example, where they do not have opposite charges. The neutron has a zero net charge, and it is the same for its antiparticle, the antineutron. Instead, they have opposing magnetic moments. So, the antineutron will have a magnetic moment opposite to the neutron's magnetic movement. This remains the case for the neutrino and its antiparticle, the antineutrino. The neutrino, seen from behind at relativistic speeds, matches the antineutrino, which spins clockwise as seen from behind at the same speed as the neutrino. Although it was discovered in 1932 by Carl D. Anderson, Paul Adrien Maurice Dirac predicted the existence of the antiparticle in 1928 due to his relativistic quantum theory of the electron. This theory stated that the electron has a spin quantum number of ½ and a magnetic moment. Although his hypothesis had unexplained and extra solutions, Dirac had not realized the importance of this unexplained phenomenon, which would later be known as the antiparticle. This only became known after Anderson discovered the first known antiparticle, the positron, also known as the antielectron. The discovery of antiparticles through Dirac’s quantum theory of electrons is very significant because, in theory, it establishes the existence of an antiparticle for every existing subatomic particle.



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