So, to the outside observer, light has traveled a bit further than 1 rocket ship length. Since the observer knows that it takes light 1 second to travel 1 rocket ship length, the observer measures the elapsed time for the event to be more than 1 second. He says that the clock in the rocket ship is running slow. The moral of the above story is that, due to relativity, time can slow down, as you measure it for other people. Now consider someone at the event horizon of a black hole.
Light travels away from that person at the speed of light.
General relativity states that there is no experiment that can tell whether you are standing in a gravitational field, or undergoing a constant, straight line acceleration. This latter statement has interesting consequences for the behavior of space. In effect, is says that even the path of a light ray can get curved by a gravitational field. This being the case, an alternative description is that space-time itself is distorted by the presence of mass. Normally, space is only curved a small amount, but strong gravitational fields can create large warps in space.