>It’s also worth noting (and I’m not that up to date on this so someone correct me) that the Big Bang isn’t like everything just started expanding from a single point at the speed of light. It’s more like all of a sudden everything just was. Not instantaneously, but in a matter of seconds the early universe just was, and it was big (millions? Billions? of light years big). And from that point it began to rapidly span outwards.

The idea is that all the energy and space started out packed together densely, then rapidly expanded everywhere at once similar to how space is expanding everywhere at once today. Even when it was packed together densely, it could have been infinitely large. Just denser than it is now.