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'''String theory''', (or super-string theory when coupled with [[Supersymmetry]]), is a class of models in [[theoretical physics]] which replace zero-dimensional points (particles) in four-dimensional spacetime with one-dimensional strings in an eleven-dimensional spacetime as the fundamental building block of the universe. The elusive goal is to develop a set of equations that unify all known natural forces (gravitational, electromagnetic, weak, and strong), according to some preconceived philosophical beliefs about how they ought to be unified. Leading proponents of string theory have been Edward Witten of the [[Institute for Advanced Study]] and [[Brian Greene]], the renowned author of ''The Elegant Universe''.
'''String theory''', (or super-string theory when coupled with [[Supersymmetry]]), is a class of models in [[theoretical physics]] which replace zero-dimensional points (particles) in four-dimensional spacetime with one-dimensional strings in an eleven-dimensional spacetime as the fundamental building block of the universe. The elusive goal is to develop a set of equations that unify all known natural forces (gravitational, electromagnetic, weak, and strong), according to some preconceived philosophical beliefs about how they ought to be unified. Leading proponents of string theory have been Edward Witten of the [[Institute for Advanced Study]] and [[Brian Greene]], the renowned author of ''The Elegant Universe''.
String theory (and its alter ego M-theory) is currently the most viable candidate for a unified theory of physics which describes all forces of nature, encompassing the physics of gravity as well as quantum field theory. Major research centers include, for example, MIT, with five faculty members and numerous postdocs and graduate
students working in this area.<ref> see [http://ctp.lns.mit.edu/research-strings.html MIT Center for Theoretical Physics]</ref>
Princeton University researchers have found new mathematical evidence that some of string theory's predictions mesh closely with those of a well-respected body of physics called "gauge theory," which has been demonstrated to underlie the interactions among quarks and gluons, the vanishingly small objects that combine to form protons, neutrons and other, more exotic subatomic particles. The discovery, say the physicists, could open up a host of uses for string theory in attacking practical physics problems.<ref>See [http://www.princeton.edu/main/news/archive/S17/80/32S21/index.xml?section=newsreleases "Princeton physicists connect string theory with established physics," May 1, 2007] </ref>
==Falsifiability==
There is much debate on whether string theory is truly scientific. Under the [[positivist]] philosophy, models must be falsifiable (i.e. it must be possible to define an experiment which could contradict the theory) for them to qualify as science, and then they must survive these tests. In more general terms, a model is not scientific unless we can use it to make predictions about the world we observe, and it is consistent with those predictions. String theory has yet to yield a particular definitive test, or to produce any models that resemble any known particles or forces.
There is much debate on whether string theory is truly scientific. Under the [[positivist]] philosophy, models must be falsifiable (i.e. it must be possible to define an experiment which could contradict the theory) for them to qualify as science, and then they must survive these tests. In more general terms, a model is not scientific unless we can use it to make predictions about the world we observe, and it is consistent with those predictions. String theory has yet to yield a particular definitive test, or to produce any models that resemble any known particles or forces.
==External links==
==External links==
[http://www.pbs.org/wgbh/nova/elegant/ ''The Elegant Universe''] (Nova TV Series discussing Strings)
* [http://www.pbs.org/wgbh/nova/elegant/ ''The Elegant Universe''] (Nova TV Series discussing Strings)
* [http://athome.harvard.edu/programs/sst/ "String Theory, Black Holes, aand the Fundamental Laws of Nature" (Harvard@Home 2007)]
====references====
<references/>
[[Category:Physics]]
[[Category:Physics]]