Black holes are the result of the gravitational collapse of a massive star (at least 10 to 15 times more massive than our sun).  When the star is no longer able to create outward energy to balance the strong inward gravitational forces, the star collapses into an infinitely dense black hole.  The escape velocity needed to overcome the gravity of the black hole is faster than the speed of light, hence the blackness.  One common misconception I hear is that black holes suck things in.  Black holes do not suck anymore than any object of similar mass in the universe.  If our sun was to magically turn into a black hole of the same mass (although realistically its ultimate fate is to become a white dwarf), the earth’s orbit would not change.  The gravitational energy depends on the object’s mass.  We would not be pulled into its powerful grasp unless we entered the event horizon, which is the point of no return near a black hole.  So everybody quit hating on black holes, saying they suck.  You suck.  You white dwarf.

Note:  A friend just brought this to my attention—  as white dwarfs (dwarves?) lose energy and they are no longer able to emit light, they become the hypothetical black dwarfs.  There are no known black dwarfs in the universe, because it takes longer than the age of the universe in order for a white dwarf to become a black dwarf.  That’s a long time.  But it makes sense.  Because once you go black, you never go back.