Abstract <p>A new representation for the field strength of the quasiclassical gravitational field of a continuous medium is proposed, which makes it possible to describe the effect of hidden mass or dark matter in a new way. The connection of the new representation with the properties of a continuous medium and the role of these properties in the formation of the hidden mass effect are discussed. Based on the results obtained, a new model of the structure of disk galaxies and their own evolution under dynamic equilibrium conditions is being investigated. A general classification of possible types of spatial structures of disk galaxies is given. The existence conditions of disk galaxies with bulges and jets, as well as ring structures, are considered. A qualitative analysis of possible variants of the galaxies’ own evolution and the conditions of their spatial oscillations is carried out.</p>