Exploring the dark Universe with gravitational waves
Abstract
More than a century after Einstein formulated his theory of gravitation, general relativity remains at the center of our understanding of the Universe. LIGO-Virgo's detection of gravitational radiation from coalescing binaries of stellar-mass black holes and neutron stars opens a new observational portal to previously inaccessible astrophysics and fundamental physics. The planned space mission LISA will extend our reach to the massive black hole at the centers of galaxies, while efforts to detect gravitational waves using arrays of millisecond pulsars are on the verge of revealing nanohertz radiation from even heavier black holes.