Learn about astrophysical sources of gravitational waves in this lecture from the "Hearing beyond the standard model with cosmic sources of Gravitational Waves" program at the International Centre for Theoretical Sciences. Explore the groundbreaking field of gravitational wave detection, focusing on waves produced by merging black holes and neutron stars. Examine how gravitational waves can probe physics beyond the Standard Model, including phenomena like inflation, Primordial Black Holes, Phase Transitions, and topological defects. Discover the significance of Stochastic Gravitational Wave Background (SGWB) signals and their detection by collaborations like NANO-Grav and InPTA. Understand the implications of these discoveries for high-scale physics research and potential modifications to general relativity theory through the expert insights of Parameswaran Ajith.