The initial hyper inflation of space from the size of a grape fruit onwards would have expanded as a balloon would expand at the speed of light.

A micro black hole event horizon would stay in that expanding balloon of energy.
All the energy gamma rays and such would have been expanding.
The micro black hole would have been drawing that energy in.

As soon as the micro black hole gained mass would fall behind.
Its event horizon would stay with the expansion.
The mass would not and would form a structure like a worm hole.

These structures went on to be the filaments of density detected in space.

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