The basic concept of a black hole is that you're either in or you're out. Anything that falls into a black hole is lost to the outside universe -- it can never come back out. Yet there's a sort of transition zone between a black hole and the rest of the universe. This region swirls with matter and energy, and with monstrous magnetic fields. And it can have an impact on the stars around it, on the entire galaxy, or on the entire universe.
The transition zone is particularly impressive around a supermassive black hole -- one that's millions or billions of times heavier than the Sun. These black holes are found in the hearts of many galaxies -- including our own.
The gravity of a supermassive black hole accelerates the stars around it like pats of butter in a blender. It can also pull in stars and gas, forming a broad, flat disk around the black hole. As matter in the disk spirals closer to the black hole, it gets hotter and hotter. As it heats up it emits ultraviolet light, then X-rays -- energy that may clear out a cavity around the black hole.
The spinning disk produces a powerful magnetic field that can fling particles back out into space -- in essence, creating a giant particle beam. Some may become cosmic rays -- particle "bullets" that can cross the universe. More about that tomorrow.
All this activity can transform the space around a black hole into a hot, busy, deadly zone -- a turbulent transition between in and out.
Script by Damond Benningfield, Copyright 2007
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