His research now focuses on gravitational self-force, which is the force on a body moving through a gravitational field arising from the mass and energy of the body itself. This self-force is expected to play a crucial role in understanding the motion of a stellar mass black hole orbiting and eventually spiraling into a supermassive black hole such as those that reside at the centers of galaxies. These astronomical systems will be of special interest to space-based gravitational wave detectors such as Laser Interferometer Space Antennae when they are built, because they will allow precision measurements of the gravitational field of a black hole for the first time.