The electric dipole moment of a pair of virtual particles (a PVP), particle-antiparticle, produced in the physical vacuum by an electron, is discussed. The emergence of superconductivity in a medium can be attributed to the formation of pairs of electrons with the total electric dipole moment of the PVPs produced by the electrons in such a pair being less than a certain critical value. In this case the medium viscosity will decrease due to the disappearance of the electric dipole interaction of pairs of the electrons. It is supposed that the Cooper pairs in superconductors are such pairs. An equation is derived which establishes a relationship between the critical value of magnetic field strength and the temperature of the superconductor. The role of the electric dipole interaction of the PVPs in the Cooper pairing is discussed.
