Editing M-theory (section)

===Second superstring revolution===

[[File:Limits of M-theory.svg|upright=1.6|thumb|alt=A star-shaped diagram with the various limits of M-theory labeled at its six vertices.|A schematic illustration of the relationship between M-theory, the five [[superstring theory|superstring theories]], and eleven-dimensional [[supergravity]]. The shaded region represents a family of different physical scenarios that are possible in M-theory. In certain limiting cases corresponding to the cusps, it is natural to describe the physics using one of the six theories labeled there.]]

{{main article|Second superstring revolution}}

Speaking at [[Strings (conference)|Strings]] '95 at the [[University of Southern California]] in 1995, Edward Witten of the [[Institute for Advanced Study]] made the surprising suggestion that all five superstring theories were in fact just different limiting cases of a single theory in eleven spacetime dimensions. Witten's announcement drew together all of the previous results on S- and T-duality and the appearance of two- and five-dimensional branes in string theory.<ref>Witten 1995</ref> In the months following Witten's announcement, hundreds of new papers appeared on the Internet confirming that the new theory involved membranes in an important way.<ref>Duff 1998, pp. 67–68</ref> Today this flurry of work is known as the [[second superstring revolution]].<ref>Becker, Becker, and Schwarz 2007, p. 296</ref>

One of the important developments following Witten's announcement was Witten's work in 1996 with string theorist [[Petr Hořava (theorist)|Petr Hořava]].<ref name="Hořava and Witten 1996a">Hořava and Witten 1996a</ref><ref>Hořava and Witten 1996b</ref> Witten and Hořava studied M-theory on a special spacetime geometry with two ten-dimensional boundary components. Their work shed light on the mathematical structure of M-theory and suggested possible ways of connecting M-theory to real world physics.<ref>Duff 1998, p. 68</ref>