it has transitioned from so many ideas and theories it's hard to know what really came first. these are me favorite theories: it's been said the earth is flat.
that earth is as if we were turned inside out! and the stars and everything we see in the sky was the center. (like those gumballs that are hollow and have nerds or another type of candy in them) and when you opened it up we were the outer walls and the candy in the center was all we can see when we look up.
then there is the normal theory that rocks and such clumped together. therefore we are not smooth and round. and the universe is everywhere, spinning, creating, and breathing.
hoped I answered that correctly.