Possibility of the development of explosive instability in a two-stream gravitating medium

An expression for the energy of the density wave in a multicomponent gravitating medium is obtained that is similar to an appropriate expression in electrodynamics of continua. The possibility of birth of a wave triplet including both positive and negative wave energies in a nonequilibrium gravitating medium is demonstrated. It is shown that such a resonant interaction of waves leads to the development of explosive instability. An expression for the characteristic growth time of instability within a one-dimensional model is obtained by a method developed in plasma physics.