Joint seminar organized by APC (University of Paris) and Service de Physique Théorique (ULB, Brussels)

Resonances are ubiquotous in nature. In this first part of this talk, I will focus on resonances due to the interaction of two black holes orbiting a central massive black hole. I will discuss both mean motion resonances and tidal resonances in EMRI spacetimes. The second part will be about the resonances in neutron stars. In particular, I will focus on the interface mode that lives near the core-crust boundary and can be excited in the final phases of a binary inspiral. When such a resonance occurs, orbital energy is transferred to the star resulting in the melting of the crust. This is likely observable by the third generation gravitational wave detectors.