Hunting Black Holes

Black holes are pitch black celestial objects which suck in even light. Matter and light that are pulled in are unable to ever escape again. But is it possible to use observations to find these dark celestial objects known as black holes? The gas which is pulled in by the black hole forms a radiant disk right before it is consumed by the black hole. There are also cases where strong jets are ejected from the disk. By observing these jets and the light radiated by the disk, we can find black holes which should be invisible.