What the soup looks like.
Well, the pool is not made of rock... entirely.
I guess I've been thinking that 'space', interstellar space, is pretty much void of any rocks to think otherwise for so long, but, as for the soup contents (actual rocks/matter, visible light, radiation, etc., this is how most people see that 'soup':
http://www.anzwers.org/free/universe/universe.html
Marcia