In 1898, Arthur Schuster, a British physicist, coined the phrase "antimatter" when he hypothesized that there existed entire cosmological systems composed of antimatter that were identical to our own solar system. He suggested that matter and antimatter, upon collision would annihilate each other, producing an enormous quantity of energy. His suggestion anticipated the concepts of special relativity and quantum physics.

At beginning of the 20th century, the appearance of two new theories, relativity and quantum mechanics, shook the world of physics.

In 1905, Albert Einstein revealed his theory of Special Relativity, wherein his renowned equation E=mc² explained the correlation between space and time, and between energy and mass. In the interim, experiments had established that light sometimes behaved as a wave, and other times as a particle. Max Planck postulated that this was because every light wave came in a small packet of energy, which he called a "quantum," hence, light was not just a wave or just a particle, but rather both.

By the end of the 1920's, Erwin Schrödinger and Werner Heisenberg developed the new quantum theory of physics; however, it was not relativistic, meaning that the quantum description did not work for particles at high (relativistic), near the speed of light, velocities, but instead at low velocities.

Paul Adrien Maurice Dirac

In 1928, Paul Dirac, a British theoretical physicist, derived an equation, which combined the new quantum theory and special relativity, to describe the behavior of the electron, and hence solving the problem. On the other hand, the equation posed a different problem in that it could have two solutions, one for an electron with negative energy, and one for an electron with positive energy (positron). Dirac theorized this to mean that for every particle there exists a matching antiparticle with opposite charge. His equation won him the Nobel Prize in 1933.

Carl David Anderson

In 1932, as Carl Anderson, an American experimental physicist, studied showers of cosmic particles in a cloud chamber, he saw a track left by "something positively charged, and with the same mass as an electron". He concluded that the tracks were actually anti-electrons. He called them "positrons," for their positive charge. The discovery earned Anderson the Nobel Prize in 1936 and confirmed Dirac's theory of the existence of antiparticles.

In 1930, Ernest Lawrence, a Nobel Prizewinner in 1939, invented the cyclotron, a machine that eventually could accelerate a particle like a proton up to substantial energy. The project was driven by the effort to discover the antiproton. In 1954, Lawrence also built the Bevatron at Berkeley, California. Meanwhile a team of physicists, headed by Emilio Segre, designed and built a special detector to see the antiprotons.

Emilio Segre

In the 1955, Segre and other physicists at the Lawrence Radiation Laboratory used the Bevatron accelerator to create an anti-proton. In order to create the anti-proton, protons were accelerated to a very high energy and then smashed into a proton target. The energy that was brought into the collision resulted in the emergence of a proton-antiproton pair in addition to the original two protons. With the discovery of the antiproton, Segre and the other physicists had succeeded in providing further evidence for the essential symmetry of nature, between matter and antimatter. A few years later, the antineutron was also discovered at the Bevatron.

After the discovery of the positron, anti-proton and anti-neutron, Dirac's Theory of Symmetry speculated on the existence of anti-planets, and anti-stars.

Since matter is made up of atoms that contain their specific quantities of protons, neutrons and electrons, the discovery of antiparticles for each of these constituents to the atom, warranted the creation of antiatoms, and in the long run antimatter.

One of the foremost institutions involved in the creation, development, and study of antiparticles is the European Organization for Nuclear Research, commonly known as CERN. It is the world's largest international particle physics laboratory, and is situated in Geneva. Founded in 1954 its main function has been to provide particle accelerators and other infrastructure needed for high-energy physics research.

Brookhaven National Laboratory (aerial picture)

In 1965, two teams of physicists, one led by Antonino Zichichi, using the Proton Synchrotron at CERN, and the other led by Leon Lederman, using the Alternating Gradient Synchrotron (AGS) accelerator at the Brookhaven National Laboratory (BNL), New York, simultaneously achieved the creation of the antideuteron, a nucleus of antimatter made out of an antiproton plus an antineutron.

Unique to CERN, physicists used the Low Energy Antiproton Ring (LEAR), which contrary to an accelerator, actually "slowed down" antiprotons, and forced a positron to stick to an antiproton, resulting in an antihydrogen atom, and actual antimatter atom. In 1995, a team of German and Italian physicists at CERN produced the first such antiatoms. The LEAR was afterward replaced with the current Antiproton Decelerator (AD), which can produce, collect, cool, decelerate and eventually extract antimatter to the experiments. In 2002, the AD made headlines around the world when its ATHENA and ATRAP experiments successfully created and trapped thousands of antiatoms in a "cold" (slow moving) state.

As physicists using particle accelerators periodically discover ever more exotic particles that are unstable and rarely or never seen in nature, the discovery of the corresponding antiparticle is usually quick to follow. Sometimes the antiparticles are the ones discovered first.