Ifrared telescopes have observed starts orbiting our galaxy’s central black hole for decades. The ngVLA will reveal the faint signals of pulsars that also orbit the black hole. The motion of pulsars can be measured with a million times more accuracy than that of stars. These pulsars can be used as celestial clocks to study the effects of gravity on motion and time. This will let us test Einstiens’ theory of gravity in new ways, and may provide clues to physics beyond the standard model.