Modelo estándar, un manual de instrucciones para entender el universo

Grand unification and its even grander super-extensions all point to the stunning conclusion that the relative strengths of the particle forces, the masses and species of particles, and perhaps even the mere existence of matter and forces aren’t mathematical truths carved in stone but fossil relics of an ancient and largely hidden epoch of evolutio

Certain special arrangements of hidden dimensions correspond to universes with laws nearly identical to the ones we observe, differing, say, only in the precise values of a few particle masses. Such universes could be equally biofriendly—if not more.

in all, the model contains about twenty parameters, key numbers such as particle masses and force strengths, whose often surprising values are not predetermined by the theory but must be measured experimentally and inserted into the formulas by hand. Physicists usually refer to these parameters as constants of nature,