The atomic nucleus

Beginning in 1911, starting from the instant of the discovery of the atomic nucleus by Rutherford, physicists have made attempts to gain an understanding of the constitution of the atomic nucleus. Each nucleus is a complex unique object that consists of a finite number of neutrons and protons. It is shown in this review that the concept of the atomic nucleus changed as a large amount of experimental data was accumulated, understood, and theoretically analyzed. As a result, new types of interactions that were previously unknown in physics, such as the strong and weak interactions, were discovered; new phenomena associated with the mutual transformation of the particles were revealed; new types of symmetry, particularly spatial symmetry, were found; and new experimental methods were developed. As well, accelerators, which made it possible to observe the variations of separate atomic nuclei for the first time, were designed. Investigation of the properties of atomic nuclei opened a new world, viz., the subatomic quantum world. This knowledge is important in natural sciences, from the investigation of living organisms to astrophysics.