What Is Antimatter?

You may have heard about antimatter in the context of science fiction or particles accelerators, but antimatter is a part of the everyday world. Here is a look at what antimatter is and where you might find it.

Every elementary particle has a corresponding anti-particle, which is antimatter. Protons have anti-protons. Neutrons have anti-neutrons. Electrons have anti-electrons, which are common enough to have their own name: positrons. Particles of antimatter have a charge opposite that of their usual components. For example, positrons have a +1 charge, while electrons have a -1 electric charge.

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Atom Definition and Examples

By Anne Marie Helmenstine, Ph.D.

Antimatter Atoms and Antimatter Elements

Antimatter particles may be used to build antimatter atoms and antimatter elements. An atom of anti-helium would be comprised of a nucleus containing two anti-neutrons and two anti-protons (charge = -2), surrounded by 2 positrons (charge = +2).

Anti-protons, anti-neutrons, and positrons have been produced in the lab, but antimatter exists in nature, too. Positrons are generated by lightning, among other phenomena. Lab-created positrons are used in Positron Emission Tomography (PET) medical scans. When antimatter and matter react the event is known as annihilation. A great deal of energy is released by the reaction, but no earth-ending dire consequence results, like you would see in science fiction.

What Does Antimatter Look Like?

When you see antimatter depicted in science fiction movies, it's usually some weird glowing gas in a special containment unit. Real antimatter looks just like regular matter. Anti-water, for example, would still be H₂O and would have the same properties of water when reacting with other antimatter. The difference is that antimatter reacts with regular matter, so you do not encounter large amounts of antimatter in the natural world. If you somehow had a bucket of anti-water and threw it into the regular ocean, it would produce an explosion much like that of a nuclear device. Real antimatter exists on a small scale in the world around us, reacts, and is gone.