Why are Black holes often shown like this? What is with the 900 bend?
There we go.
It’s an artist’s impression possibly aided by CGI, based on what the physics of the situation imply a black hole would look like. The first thing to note is that this particular example is of a black hole, possibly a spinning one, that is surrounded by an accretion disc, similar to Saturn’s rings, composed of interstellar dust and gas. The glow is the result of gas particles fluorescing as they are accelerated in the fierce gravitational field. The glow is also red-shifted by gravity. All the visible features are of course outside the black hole’s event horizon, below which no light can escape.
The actual view of the black hole is side-on with the accretion disc and the viewer (almost) in the same plane. But the intense gravity near the black hole also explains the strange appearance of the accretion disc. Basically, light rays are curved by gravity (the closer to the event horizon, the greater the curvature), so the images of the parts of accretion disc that are behind the black hole are smeared around the periphery of the hole.
'Luthon64
Thank you for the explanation.
A while ago I watched a very well explained description of what you see when looking at a black hole.