Q:
How long do we have before the Sun goes supernova and fries us? Supposing this does happen, are any other planets capable of maintaining human life?
A:
Astronomers believe that our star, the Sun, is not massive enough to become a supernova. Instead, in about 5 billion years it should dramatically expand to become a red giant and will fry the Earth in that way. It's less dramatic than with a supernova, but the Earth will eventually be destroyed. There are probably many other planets in our galaxy that are capable of maintaining human life, but astronomers haven't detected any planets like this because our telescopes are not yet powerful enough.
Information on Tidal Disruption in the Milky Way:
http://chandra.harvard.edu/photo/2004/rxj1242/tidal_disruption_in_milky_way.html
Revised: September 05, 2008