It still boggles my mind that all of this began as a Singularity...a single, dimensionless point in time and space...and expanded into what we see today. Given that we know the universe is still expanding, what’s it expanding into? I’m not smart enough to understand this.
The big bang, despite its acceptance is still just a theory. My biggest problems with it are the fact that science has removed certain physical properties to explain its earliest seconds.
Think fireworks.