Snuff, it's one of those things that are out of our omprehension.
Relativity says that the total velocity realtive to an outside observer cannot exceed that of light. If you are travelling at 1/2 c, and shine a torch ahead, its beam still only moves forward at c according to the obseever. But ithe beam moves fward at c as far as you're concerned...
The answer (if you can call it that), is that, to the obsever, your clock has slowed such that the torch beam still moves forward at c
