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"