The goal of this project is to perform stringent tests of fundamental physics using both the strongest gravitational fields in the universe and relativistic binary radio pulsars. Advances in LIGO technology have meant we are now routinely witnessing the merging of stellar-mass black holes, where the gravitational field at their horizons is ten billion times stronger than in the solar system. Our team’s expertise in general relativity, Bayesian inference, and signal processing are allowing us to test Einstein’s theory in these ultra-strong-field regimes. We are measuring strong-field effects predicted by Einstein’s relativity and providing robust constraints on physics. We are gaining insights from the exquisitely precise timing measurements of relativistic binary pulsars using the MeerKAT, Parkes and ultimately SKA telescopes. ​