Frankly, the world as we know it is going away, soon.

[kurt_cagle]

116. Um, no .. sorry

Sorry to be pedantic here, but the sun will never become a black hole.

1.2 billion years from now, the sun will get hot enough to start evaporating earth's oceans (water vapor becomes energetic enough to escape earth's gravity well), with the earth going through a Venusian Greenhouse stage before eventually losing all of its volatiles by 3 billion year. Figure the biosphere has maybe 1.5 billion years left in it.

In 4.5 billion years, the sun will go nova, becoming a red giant as it begins consuming it's built up helium. The earth at that stage will likely be consumed as the sun expands out to about 110 million miles (still inside the orbit of Mars, which will be about where Venus is now). This will continue for another 1.5 to 2 billion years until helium gets depleted and pressure induced carbon to start fusing. With the mass of the sun, the initiation of the carbon cycle will cause the outer layers of the sun to blow off into space.

What remains will be a white dwarf, which is a star where the material is degenerate (with extreme densities). You can think of a white dwarf as a highly condensed diamond lattice. That white dwarf is different from a red dwarf, which is simply a low mass star such as Proxima Centauri or Gliese that has just enough fusion process to burn for upwards of 100 billion years (one reason Gliese is so much in the news lately, as it is also a star system with at least five and maybe six planets, including one that could be earthlike). Brown dwarves are even lower intensity stars that are at the very threshold of viability as stars - much smaller, and they would up as giant planets.

White dwarves have energy due to gravitational attraction and high density, but it no longer undergoes fusion. This means that it will slowly lose energy and eventually will become a black dwarf, but that process takes a long time - some hundred billion billion billion billion years. Our universe is comparatively young - there are no black dwarves out there yet.

A neutron star is formed when the initial star is between 1.4 and 3.2 solar masses. These are more dense than white dwarves - you can think of them as essentially being giant singleton atoms. They are noted for their incredibly rapid spin, often spinning on its axis several dozens or hundreds of times a second, and their energy jets as the intense magnetic fields of these start draws in material from elsewhere and then redirects it along its rotational axis.

A black hole is not the end state of a black dwarf. The initial star would have to be greater than 3.2 solar masses for one to form. These become so dense that eventually light itself is unable to escape.

Finally, there is a theoretical hyper-dense object known as a quark star with neutron starts close to the 3.2 solar limit (the Chandrasekhar Boundary) where the outer layers of the neutron stars actually degenerate into a quark "crust". This is one of the candidates for dark matter in the universe.