Within that soup, what sort of chunks of complexity do we find?
In the first few seconds, almost none.
The most basic tiny particles just emerging.
There are about 200 elementary particles known to science.
Of these, the collection of quarks, the ingredients for the protons and
neutrons of atoms were not able to come together in that intense fireball to
form more complex structures or systems.
Without the ability of building blocks to come together,
you can't really have structures through which energy can flow.
Without flow of energy you don't really have any complexity.
After the first few minutes, quarks formed protons and neutrons.
And in turn protons and neutrons began to form the nuclei of atoms.
This is because of the expansion of the universe,
which made the first real complexity possible.
Over the next few centuries, the universe cooled to a temperature and
densely comparable to most stars today.
Nevertheless, because matter and radiation were intimately coupled,
the early universe remained a uniform highly structural blob.
Not a lot of energy flow.
Not a lot of structure.
Not a lot of complexity.
The reason why the early universe was so hot is because of pressure.
Throw all the ingredients of the cosmos into a concentrated heap and
heat is generated.
The same goes to a much lesser degree for the massive clumps of hydrogen and helium
gas that form a star, or the molten core of a sufficiently large planet like Earth.
But then, let us back up, why did any complexity emerge in the universe at all?
Why wasn't the universe born stillborn, uniform, dead, at equilibrium,
without any future for complexity in the cosmos?