Everything we can observe in the Universe appears to be moving away from everything else.
So, we can logically deduce that at some point back in time, everything was closer to everything else.
Take it back far enough, and it appears that everything would come to 1 point.
A super dense, super energetic point.
The laws of physics that we know, wouldn't exist at that point.
Then everything 'exploded' from that point. But if I understand it correctly, it isn't exploding into anything, ie there is nothing outside our universe, it's just expanding within itself.
Does it make sense? No. Is it correct? Maybe not. But it does appear that everything we can see, once came from a single point.
It wouldn't have been a hydrogen atom, it wouldn't have even been a sub atomic particle, not one that we can observe now, anyway.
It would have been something akin to the centre of a black hole, but even denser and more energetic.
