In this theory the big bang is just the latest big bang in an endless stream of big bangs in the continual expansion collapse and renewed expansion of space and time.
Big bang theory timeline.
Timeline of the big bang theory.
Due to the extreme conditions and the violence of its very early stages it arguably saw more activity and change during the first second than in all the billions of years since.
The discovery of quasars supported the big bang theory and went against the steady state theory.
Models that aim to describe the universe and physics during the planck epoch are generally speculative and fall under the umbrella of new physics.
According to the steady state theory these quasars should be found all throughout the galaxy but they are only found on the outskirts which supports the big bang theory in which the universe is constantly expanding.
In inflationary models of cosmology times before the end of inflation roughly 10 32 seconds after the big bang do not follow the same timeline as in traditional big bang cosmology.
Since the big bang 13 7 billion years ago the universe has passed through many different phases or epochs.