Superstring theories are consistent with what we know, but critics, of which there are still quite a few, claim that they are too mathematically abstract to predict anything which can be experimentally tested and verified, as should be possible with a proper scientific theory. Its supporters claim that the theories suggest that there should be a class of particles called supersymmetric particles, where every particle should have a partner particle. CERN, the European Organization for Nuclear Research, recently opened their Large Hadron Collider (LHC), the world’s largest and highest-energy particle accelerator, near Geneva on the border between France and Switzerland. There are those who hope that the LHC will be able to detect signs of supersymmetric particles. If so, this finding will not by itself prove superstring theory, but it would constitute a strong piece of circumstantial evidence in its favor.- - - - - - - - -
Personally, I would still count myself among the skeptical half regarding string theory. The critics who complain that it is unnecessarily complex with precious little experimental evidence in its favor have a point. It does seem rather drastic to go from four to eleven dimensions, thereby nearly tripling the amount of dimensions in the universe. As it is now, the theory contains too many epicycles for my taste. However, just because a theory is complex and seemingly counter-intuitive does not necessarily mean that it is wrong, as quantum mechanics and to some extent the theory of relativity showed us in the twentieth century.
One humorous illustration of how hard it is to imagine extra dimensions was provided by the English writer Edwin A. Abbott (1838-1926). His satirical novel Flatland: A Romance of Many Dimensions from 1884 is narrated by a being who calls himself “Square” and lives in Flatland, a world populated by two-dimensional creatures with a system of social ranks, where creatures with more sides rank higher and circles highest of all. Women are merely line segments and are subject to various social disabilities. In a dream, Square visits the one-dimensional Lineland, and is later visited by a three-dimensional Sphere from Spaceland. The Sphere tries to convince Square of the existence of a third dimension and mentions Pointland, a world of zero dimensions, populated by a single creature who is completely full of himself.
Perhaps we are all a bit like Square, who finds it very hard to imagine extra dimensions. And most of us have encountered individuals who live in Pointland, occupied only by themselves.
Read the rest at Vlad Tepes.