This chain reaction fuels the .
star for millions or billions of years depending upon the amount of gases there are. The star manages to avoid collapsing at this .
point because of the equilibrium achieved by itself. The gravitational pull from the core of the star is equal to the gravitational .
pull of the gases forming a type of orbit, however when this equality is broken the star can go into several different stages. .
Usually if the star is small in mass, most of the gases will be consumed while some of it escapes. This occurs because there is .
not a tremendous gravitational pull upon those gases and therefore the star weakens and becomes smaller. It is then referred to .
as a white dwarf. A teaspoonful of white dwarf material would weigh five-and-a-half tons on Earth. Yet a white dwarf star can .
contract no further; it's electrons resist further compression by exerting an outward pressure that counteracts gravity. If the star .
was to have a larger mass, then it might go supernova, such as SN 1987A, meaning that the nuclear fusion within the star simply .
goes out of control, causing the star to explode. After exploding, a fraction of the star is usually left (if it has not turned into pure .
gas) and that fraction of the star is known as a neutron star. Neutron stars are so dense, a teaspoonful would weigh 100 million .
tons on Earth. As heavy as neutron stars are, they too can only contract so far. This is because, as crushed as they are, the .
neutrons also resist the inward pull of gravity, just as a white dwarf's electrons do. A black hole is one of the last options that a .
star may take. If the core of the star is so massive (approximately 6-8 times the mass of the sun) then it is most likely that when .
the star's gases are almost consumed those gases will collapse inward, forced into the core by the gravitational force laid upon .
them. The core continues to collapse to a critical size or circumference, or "the point of no return.