The string/brane theories have fallen out of favor over the last decade. No particular reason, but they were always a little "flavor of the month", more math driven than physics.
In any event Brian Green's Elegant Universe is a good read on the subject. I believe that Brane theory has us living in a 10+1 dimension universe.
In any event Brian Green's Elegant Universe is a good read on the subject. I believe that Brane theory has us living in a 10+1 dimension universe.