Gravitational radiation reaction

Summary

Gravitational radiation reaction is the effect on a source of the gravitational waves it emits. The waves carry away energy and angular momentum, and the source loses them. For a binary system the orbit shrinks and the two bodies spiral together. In the post-Newtonian expansion it first appears at order $(v/c)^5$ beyond Newtonian gravity, as a dissipative force consistent with the quadrupole formula.