The remarkable detection of gravitational waves by the LIGO/Virgo collaboration has opened a new window into the cosmos. In this colloquium we explain how particle theorists can help out with calculations directly relevant for gravitational-wave emission from compact astrophysical objects. The past decade has seen enormous advances in our ability to compute quantum scattering amplitudes making seemingly impossible calculations tractable. These advances include ideas such as the duality between color and kinematics, double-copy relations, generalized unitarity, and improved integration methods. The starting point in this approach is that gravity is transmitted by a massless spin 2 particle. After introducing these concepts, we explain how these ideas are transferred to produce new state-of-the-art calculations for the astrophysical binary black hole inspiral problem.
