The carrier particle of the strong interaction There are 8 different gluons with colour charge 2, i e the gluons are by themselves strongly interacting particles Gluons bind quarks inside proton and other hadrons
a predicted state of matter, containing deconfined quarks and gluons, present in the very early universe (first millionth of a second), and recreated at extremely high energy densities, such as those in the collision of heavy atomic nuclei as speeds very close to the speed of light