This has been asked before, but I still don't get some points about all this.
From what I've gathered so far, it's something like this:
A molecular cloud with some initial spin starts collapsing due to gravity. Because it collapses it starts spinning faster, following conservation of angular momentum. This eventually creates bigger centripetal forces, thus pressing the mass outwards. Also, up and down / vertical movement cancles itself out, so all movement is horizontal.
I dont't really understand why this explains that the original sphere flattens into a disc, though. Why can't it be multiple disc shaped objects "stacked" over each other, creating a cylindric shape, rather than a single flat disc?
Bonus question: Where does the initial spin from the collapsing gas cloud come from?
Maybe you can help me with this question!
Cheers Anton
