Originally posted by Ace
Hey... aren't black holes black for a reason? So why does the event horizon have a texture? j/k 
That's not the event horizon. The even horizon is the radius at which light can no longer escape from the black hole. That texture is the
Accretion Disk.
The accretion disc around a blackhole can be 'hot', and thus give of visible and invisible (but detectable) wavelengths of energy. The accretion disc exists from the very edge of the event horizon, out to a fixed distance determined by the size (mass) of the black hole in question.
A very good example of a hot accretion disc would be a collapsar in a co-orbit with another massive stellar object, like I yellow giant. The singularity pulls matter from the upper atmosphere of its partner. The stolen matter spirals into the event horizon, accellerating unto its own oblivion. Acceleration adds energy to the matter, which must be given up as light and heat (usually in the form of X-rays and gamma rays, but also as visible wavelengths).
Of course, I could just be paying too much attention to details in a kickass render (even if it should have been a Raziel).
