My understanding of the Big Bang Theory (BBT) is that approximately 13.77 billion years ago a certain singularity came into existence “with a bang”. It was incredibly – infinitely? – dense and small, and it exploded into existence. The explosion was the beginning of the expansion.
The Big Bang (BB) has been held to be the beginning of everything. It doesn’t even make sense to say “what happened before the BB” because there was no before the BB. Time began “with a bang”. It doesn’t even make sense to say “where there was nothing, there arrived something” because there
. . . → Read More: Death By Trolley: Help Me Better Understand The Big Bang Theory