The development of the Universe
I cannot pretend that the following is certain or the absolute fact. It is clear that no one knows with absolute certainty. However this is a simplified summary of current "best guess".
The huge period over which the universe has been developing and expanding is divided into very unequal sections. These are not absolute, we think that there was a good deal of overlap between the processes.
Rapid inflation
The diagram does look slightly rude but ignoring that, from the beginning of time, space, the universe and everything the new universe experiences super-fast inflation. From the size of a nucleus to the size of a grapefruit in a tiny fraction of a second. The Laws of Physics as we understand them did not seem to apply.
2 Inflation slows
The rate of inflation slows and the universe is a seething mass of fundamental particles such as quarks and
electrons. The fundamental forces begin to take effect.
3 Quarks and electrons
The rate of inflation slows and the universe is a seething mass of fundamental particles such as quarks and
electrons
4 Super hot fog
Still too hot for atoms to form the universe is a super-hot fog.
5 Atoms form
Electrons combine with protons and neutrons to form atoms (almost all hydrogen and
helium). At this stage the Universe is still dark. Any light is quickly absorbed by close packed excited atoms
6 Stars and galaxies begin to form.
Small variations in the density of the universe allows gravity to cause the gases to clump together into huge clouds which will form galaxies within which smaller clumps will form the first stars. At this stage the Universe is transparent but the first stars did not begin to shine until about 1 billion years from the Big Bang so until then there were no sources of light.
7 First supernova
The first huge stars die in supernovae exploding heavy elements into the clouds nearby. The shock waves and the heavy elements kick start the formation of
new stars and solar systems. The rate of expansion of the Universe is accelerating.
