I read that the determining factor of a Black Hole being created is when the mass of an object divided by its radius exceeds a critical point. If the number is more then this critical point then it is a Black Hole; if the number is less then this critical point then it is not a Black Hole. Also, I read that if you replay the expansion of the universe in reverse, it leads to an extreme amount of mass in a small amount of space and eventually leads to the Big Bang theory. My question is, if the only determining factor of Black Hole creation is mass divided by its radius exceeding a critical value, then it seems like the entire universe would have been a Black Hole for many of years after the Big Bang? And would remain a Black Hole until the universe had enough time to expand large enough until you could divide the mass of the universe by its radius and not end up with a number that is less than the critical value needed to be a Black Hole? Was the entire universe a Black Hole for many years?