The concept of the Big Bang refers to the rapid expansion of the universe from a highly dense and hot state. It is important to note that the Big Bang did not occur at a specific point in space. Rather, it involved the expansion of space itself. This means that all points in the universe were incredibly close together at the time of the Big Bang, and as the universe expanded, these points moved away from each other.
When scientists talk about the "beginning" of the universe in the context of the Big Bang, they are referring to the start of this rapid expansion and the subsequent evolution of the universe as we know it. However, our current understanding of the Big Bang doesn't provide insight into what might have triggered or caused it. It is a subject of ongoing scientific research and investigation.
While the concept of a singularity—where the universe is thought to have been infinitely dense and hot—is often associated with the Big Bang, our current understanding breaks down at such extreme conditions. The Big Bang theory describes the evolution of the universe from an extremely dense and hot state to its present state, but it does not provide information about what might have preceded it or whether there was a definitive "beginning" in the conventional sense.
Scientific understanding and theories about the origins of the universe are continually evolving as researchers gather more data and develop new models.