Consider a boundless Universe in which voids form, for want of a
better analogy, much like bubbles form in Swiss cheese or cavitation
occurs in water. Further, consider our universe to be like one of
those bubbles into the vacuum of which matter outgassed from the wall
of the expanding void moves, and we have everything we need to very
satisfyingly answer three long-standing, nagging questions: Where is
the missing matter?, Why does the red shift increase with distance?,
and, Why is there a horizon beyond which we can't see?

--
John Fields