A black hole is defined as a region of spacetime with a gravitational field so intense that its escsape velocity is equal to or
exceeds the speed of light. A black hole is not in the casual past of the infinite future and is excluded from some portion of the
universe. Some theories say that the universe is one giant black hole but this definition contradicts those theories.
Black holes are formed from stars. A star is defined as a self-luminous celestial body consisting of a mass of gas held together
by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface,
and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures. That characterizes a
stable star, but there are certain types of stars that are not stable, which are dying stars. A dying star has burned out all of it's fuel,
(hydrogen) when this happens it becomes unbalanced and the inward-directed gravitaitional forces take over causing the star to
collapse under it's own extremely intense pressure. After collapse, what once was a star now has no measurable length or width, this
is called a singularity. Now even though it can not be measured or even seen, the mass from the original star still exists and creates
massive gravity, any matter near will be drawn into the singularity, even light.
Many scientists believe there is at least one black hole in the center of our galaxy. But if so, it is far enough away for us or any
of the other planets to be completely safe from its or their gravitational pull. It is not likely that a black hole could form within our solar
system in our lifetime. On the other hand, there are roaming black holes and possibly even micro-black holes that roam through
interstellar space, if one of these roaming black holes were to come close enough, we would not be safe from it's...