Is There a Quantum Theory of Gravity?

Newton's law of universal gravitation is a good enough model to send spacecraft to the outer edge of the soler system, land people on the moon. We add another model, which is einstein'smodel, which is more accurate. It produces more accurate descriptions and more accurate predictions. So you can rest assured that the predictions of einstein's theory match all observations that we've made. But they also match all the rather more exotic observations we've made of the universe,. like pol sars, orbits around each other, black holes - if it didn't, it would fail.