Italy/USA and France
Alessandra Buonanno and Thibault Damour
2021 Balzan Prize for Gravitation: Physical and Astrophysical Aspects
For their leadership in the prediction of the gravitational-wave signals produced when compact objects like neutron stars and black holes spiral together and eventually merge. Their work was instrumental in the detection of gravitational waves, providing an extremely accurate confirmation of general relativity as the theory of gravitation, and allowing the LIGO and Virgo detectors to promote a type of astronomy which uses gravitational waves as new, powerful messengers of the universe.