A black hole does not have to have an incredibly large mass. It's not a large mass that makes a black hole, it's a large density.Stephen Hawking says that orbiting around a black hole would slow down time for those in orbit because of the incredibly large mass.
Why half? Are you just using that as an example?According to Hawking time would be cut down by half when in orbit.
Here I assume you mean "near the speed of light," rather than "at the speed of light."What happens? If light is constant, from Earth it would look like it's only orbiting at the speed of light, but in reality it should be going faster.
It's impossible for an object with mass to travel at the speed of light, but you could imagine the ship traveling at some large fraction of the speed of light, say 0.99999c. But note that even in the absence of gravity, if something is traveling at a large fraction of light speed their clocks will be slowed down in your rest frame, not sped up...so in the case of a black hole, the gravitational time dilation would just slow down their clock even further as measured by distant observers.I deleted the message because I thought I would find out myself. Since you replied already I'll try to explain further.
If the ship at the black hole appears from earth to be moving slower in time... then if they were traveling at the speed of light how would they look from earth? The black hole is slowing down time but they are still traveling at the speed of light, so how do they end up?