I will describe an ongoing program to apply tools originally developed for computing cross sections in collider physics to problems in classical general relativity. By leveraging on-shell techniques, effective field theory, and modern loop integration methods, this effort has enabled state-of-the-art computations relevant for current and future gravitational wave detectors. As examples, I will describe recent results for the conservative two-body Hamiltonian at the fourth order in Newton’s constant, G^4, (or fourth post-Minkowskian order), and the G^3 radiated energy in binary black hole orbits.