Problematic questions of internal structure of stars on the example of the Sun and their formation are considered. The Sun consists of two main heliospheres: the inner solid and cold core, composed of rock fragments of silicate composition, adequate to the average composition of meteorites, cemented by ice of hydrogen (predominant), oxygen, nitrogen, CO2 and others. The second heliosphere is represented by silicate melts, it is overlapped by a low-powered photosphere (essentially a boiling layer), quiet in years of a quiet Sun, fragmented when the Sun is active. The molten heliosphere is the main energy source of the Sun and other stars. Thermonuclear reactions in the cores of stars are excluded. All self-luminous cosmic objects were formed as a result of accretion from solid bodies. (correction and abbreviations are allowed).