The Big Bang was not (or not only) an expansion of matter, it's an expansion of space itself; the known universe is an enormous place that expanded out of a mic

The Big Bang was not (or not only) an expansion of matter, it's an expansion of space itself; the known universe is an enormous place that expanded out of a microscopic one. If there was space before the Big Bang, presumably it's been displaced by the sudden appearance of the entire universe as we know it. Not just the things in it but all the empty parts too, especially the empty parts.