The analysis of comparison between of Ihe planetary system of the Sun and a water molecule model is carried out. The surprising similarity of atomic orbitals in the oxygen atom as a constituent part of the water molecule and the Sun with the orbits of 8 planets has been discovered: nucleus Sun; Is orbital Mercury and Venus; 2s orbital Earth and Mars; Rp orbital Saturn, Uranus and Neptune. The analogy between two hydrogen atoms in the water molecule composition and planets with their satellites has been discovered also: nuclei Pluto and Triton; sp orbitals 1) Neptune and Nereid; 2) Uranus and Charon. A similarity is shown to exist between the tetrahedron formed by the arrangement of charges around the oxygen ions and the tetrahedron constructed by the coordinates of the positions of the corresponding planets and their satellites. The equality of some quantitative correlations in the water molecule and the solar system is ascertained: parts of planets and electrons; relative dimensions of atoms and the planetary system. The conclusion about the necessity of a thorough study of celestial bodies in the solar system is drawn, the planetary system being a possible key to the structure of atoms and molecules and to the discovery of general objective laws of the formation of similar structures.