How to Make a Cosmic Pie

The universe started out with only hydrogen and helium. And astronomers call everything above helium a metal. So if your cloud has more heavy metals in it, heavier elements, carbon, oxygen, nitrogen, even iron, then it's easier for it to coalesce. If you have really, really big clouds without any heavy metals,. then it's harder for it cool down and to coalesce - which is why the first population of stars ever formed were probably like enormous mega stars.