| Themes > Science > Physics > Elementary particle physics > Elementary particle physics Today > String Theory and the Unification of Forces > Surprises from Strings |
Researchers studying the equations of string theory soon discovered a wealth of surprises. First of all, among the particles arising as vibrations of the string, we find some which are very similar to electrons, muons, neutrinos and quarks -- the known matter particles. There are others similar to photons, W and Z bosons and gluons -- the known force carriers. And there is one particle similar to the graviton, the elusive fourth force carrier. Now since the structure of the theory is unique, we can work out (not postulate) what are the types of interaction between these particles. Astonishingly, at low energies the interactions are precisely of the type appearing in the Standard Model, and as a welcome bonus, we also get the gravitational interaction that Einstein originally discovered. So string theory predicts, roughly speaking, the right types of particles and the right types of interactions among them. The famous mathematical inconsistency -- which for decades made it impossible to incorporate quantum gravity in a theory along with the other interactions -- is conspicuous by its absence in string theory. It is almost as if gravity needs strings in order to exist |
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