Stars are matter going through a phase change. They are changing from a thin gaseous cloud to a white dwarf, neutron star or black hole. Why does this process take billions of years, not millions?
The secret is another phase change going on inside stars... the changing of hydrogen atoms into helium atoms.
That's what I talk about in this video. See this discussion in text at http://www.whiteworld.com/technoland/stories-nonfic/2008-stories/why-stars-shine.htm