Alan Guth proposed an 'inflationary' theory of the early Universe in which, during the first split second of creation and before the standard model of the big-bang, the Universe expanded exponentially, i.e., 'supercooled,' and then, in a phase change, went to a less energetic state.  In this phase change, huge numbers of pairs of particles and very heavy monopoles were created and re-heated in the big-bang (Guth 1981:347-356).  The hypothesis obviates the problems of the Universe's homogeneity and its flatness: "The ultra-rapid expansion stretches out any primordial 'wrinkles' in the the curvature of spacetime, rendering the Universe almost smooth and isotropic [or similar in all directions] on the scale we can observe"