DIAGRAM OF A BLACK HOLE

An artist's conception of a supermassive black hole with accretion disk (matter swirling into the black hole) and jets (beams of charge particles moving away from the black hole). A supermassive black hole most likely powers the intense brightness characteristic of Active Galactic Nucleus, or AGN. A quasar is one example of an AGN. The black hole pulls matter from nearby stars with such fury that the energy produced in this relatively small region (the size of our solar system) outshines the entire galaxy. Supermassive black holes contribute to half the energy output in the Universe.

NASA ANIMATION:

A larger version of this image can be found here.