The phrase "the Big Bang happened everywhere at once" emphasizes that the event was not localized to a specific point in space but rather marked the beginning of space-time itself. The Big Bang theory describes the universe expanding from a hot, dense state, with all points in the universe being the center of this expansion. The concept of a singularity, often confused with a point in space, indicates a breakdown in our mathematical models rather than a physical location. Inflation theory further refines this understanding by suggesting a rapid expansion that occurred shortly after the Big Bang, allowing for the uniformity observed in the universe today. Ultimately, the Big Bang is best understood as a moment in time rather than a singular event in space.