This incredible story is available free here. Why not load the page, save it, and read it offline. A giant disk of cold gas and dust fuels a possible black hole at the core of the galaxy. The dark, dusty disk represents a cold outer region which extends inwards to an ultra-hot accretion disk with a few hundred million miles from the suspected black hole. This disk feeds matter into the black hole, where gravity compresses and heats the material.
Hot gas rushes from the vicinity of the black hole's creating the radio jets.
The jets are aligned perpendicular to the disk, like an axel through a wheel. This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. One of the explosions to which Gentle refers. These occur because the nuclear reaction within the collapsing gasses and matter is not stable. The nuclear reaction occuring within our sun is stable but the gasses and matter within it have undergone numerous explosions and modifications in astronomical events like supernovas before they became capable of collapsing into a stable reaction.