How to Create a Black Hole Out of Thin Air

> Dr. Natarajan and her colleagues propose that UHZ-1, and so perhaps many supermassive black holes, began as primordial clouds. These clouds could have collapsed into kernels that were precociously heavy — and were sufficient to jump-start the growth of overmassive black hole galaxies. They are another reminder that the universe we see is governed by the invisible geometry of darkness.

That’s cool but - what mechanism causes the primordial gas cloud to collapse? Wouldn’t a gas cloud be characterized by matter spread very thin, as opposed to a collapsing star, characterized by extraordinarily concentrated matter packed very tightly? The path from super dense matter to black hole makes sense, the dense thing gets denser - what’s the path from super spread out thing to black hole?

"Thin air" is a weird metaphor for something that happens in space, where there is no air.