Although their existence is a virtual certainty now, black holes are still elusive objects with some strange characteristics and structure. The best candidate for a possible black hole is an object called Cygnus X-1, since that object is a strong source of x-rays. The physics of black holes tends to seem a little unbelievable. You do not want to get too close to one! Light does not travel in a straight line, in fact, it gets trapped in a black hole. Time is affected near a black hole. Something called frame dragging has apparently been confirmed around Earth as well. We have given names to the structure of a black hole. Here are some of their characteristics. Is there any way to know what goes on inside a black hole? Do they have hair? Early in the last century, Albert Einstein put forth his theory of General Relativity, which describes how matter affects space. One of the consequences of the immense gravitational field near a black hole, is that the predictions of general relativity become easy to observe. Is there evidence that Relativity is correct in its predictions?