In the beginning, says one school of cosmology, there was "ylem"*: a featureless mass of protons and neutrons containing all the matter in the universe. A little later (perhaps during the second microsecond of Creation), a "great event" took place. The ylem exploded with enough force to toss most of its matter a billion light years away. During the early moments of the resulting confusion, the protons and neutrons reorganized themselves into the chemical elements that form the present-day universe.
Cosmologists, of course, do not know that there was ever any such thing as ylem. What they do know with fair certainty...