What are Nucleons?
Nucleons -- protons and neutrons -- are atomic particles that make up the majority of mass in the matter around us. Atoms -- the building blocks of everything -- are made of up nucleons, that is, protons and neutrons, and electrons, which orbit the nucleus. An atom can be viewed as a miniature solar system, with "planets" (electrons) orbiting a central "star" (the nucleus, composed of nucleons). Electrons only have 1/1836 the mass of protons, and 1/1837 the mass of neutrons. Neutrons and protons have about the same mass.
Nucleons are rarely found independently -- they are usually tightly locked in the nucleus of atoms. They are held together by the strongest force in the universe, called (fittingly) the strong force. The strong force is about 100 times stronger than the electromagnetic force, but it only operates on extremely tiny distances -- the scale of nucleons. But when its power is released, by breaking or fusing together atomic nuclei, the results are amazing -- as in the case of atomic bombs, or the Sun, which both operate by manipulating nucleons. This is commonly known as "nuclear energy."
Nucleons are usually found in matter, but occasionally they exist independently. Radioactive decay, found in substances like uranium, slowly emit protons and neutrons in forms known as alpha radiation. This, coupled with other forms of radioactive radiation, can be harmful to humans. Space is filled with such radiation -- energetic particles traveling in straight lines at velocities close to that of light. These particles are emitted in small amounts by every star.
In particle accelerators, physicists accelerate atomic nuclei into each other at great speeds, to blast them apart and liberate a shower of particles which can be analyzed. Various exotic particles have been found in this way. For instance, in 1969, it was verified that nucleons were in fact composed of smaller particles, called quarks, held together by force-mediating particles called gluons. Before these high energy experiments, quarks had been used as a convenient theoretical construct, but it was only after the experiments that it was determined that these were in fact real particles.
Written by Michael Anissimov
