According to the Big Bang model, space and everything in it was squeezed into a infinitely small point which subsequently expanded.
But if everything is squeezed into a point of zero size than there should be no distinguishing features. i.e. everything should be crushed into a perfectly homogeneous "thing" as there are no differences of features in a point since its size is zero.
How can we understand the subsequent differentiation?
Singularities are an artefact of inadequate mathematical theories. There is no evidence they really exist. They are an indication our physical models have become inadequate at describing the physics involved.
Here is a possibility without any references, in fact there are no references available per my info on why/how big bang would have happened.
We know that singularities are formed when huge amount of matter comes together due to gravity.
It would not be unreasonable to think that the mother singularity would have formed same way - by accumulation of matter/energy due to gravity.
For big bang to happen, gravity must have somehow disappeared for just a moment. In that sense, gravity has to be self destructing given certain scenarios just like the mother singularity.
Disappearing of gravity would have resulted into the big bang. Like releasing a stretched cord.
Gravity must have re-appeared soon after big bang, but before it had time to act, inflation would have already taken place. And the expansion would have gained more momentum than what can be stopped by new appearance of gravity.
The structure formation can be attributed to the randomness in nature. There is nothing perfectly homogeneous. Things may appear to be homogeneous but at some level, they are not.
Universe is known to have gone through cycles of accelerated/slowed down expansion. Last switch from slowed expansion to accelerated expansion is believed to have happened 5 billion years ago. This cyclic observation may possibly be a hint towards an oscillating universe.
