For centuries, scientists believed that atoms are made up of three subatomic particles, electrons, protons, and neutrons. However, advanced research has proven the presence of three fundamental particles that actually compose the atom. They are quarks, neutrino, and gluon.

What Is A Gluon?

As mentioned, gluons are elementary particles that transmit a strong nuclear force between quarks. Just like the photon particles that transmit electromagnetic force between two charged particles, gluons are the exchange particles between quarks. So, they are responsible for binding protons and neutrons together in atomic nuclei.



  • Gluons are massless.
  • They travel at the speed of light.
  • As they are a type of vector boson, their spin is 1.
  • Gluons possess a property called color, which is of three varieties, arbitrarily designated as red, blue, and yellow. They also have three anticolor varieties.
  • Depending on the interaction between quarks, gluons are of eight types.


Quarks change their color within the atomic nucleus by emitting and absorbing gluons. This exchange of gluons maintains proper quark color balance. Unlike electromagnetic force, the attraction between quarks increases with the increasing distance between the quarks. Up to a certain distance, i.e., the diameter of a proton, quarks behave as if they were free of one another. This condition is called asymptotic freedom.

As the quarks move farther apart, the gluons that move between them utilize the energy drawn from the quark’s motion to create more gluons. The larger the number of gluons exchanged among quarks, the stronger the binding force. As a result, these gluons lock the quarks inside the hadrons (protons and neutrons). This phenomenon is known as confinement, which effectively limits the range of the strong interaction to 1×10−15 meters, nearly the size of an atomic nucleus.

Although in the normal phase of quantum chromodynamics (QCD), single gluons may not travel freely. However, research has predicted the existence of hadrons formed entirely of gluons, called glueballs.

At extreme temperatures and pressures, i.e., beyond the normal phase of QCD, quark-gluon plasma forms, devoid of any strong attraction. In such plasma, there are no hadrons; quarks and gluons become free particles.

Article was last reviewed on Thursday, December 2, 2021

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