More universe (uni is singular)...
My conjecture is that light decays into cosmic background radiations and further, and we simply can not see beyond the "visual limit" of the universe, not because there is not more like space or matter, but simply because it is sufficiently decayed to no longer be in visualized light spectra.
It seems that black holes would be the cosmic recycling centers, recomposing the natural entropy of matter/energy, into the cosmological constant which I believe to be the apparent opposite polar force of gravity, only at immense distance, though they are the same force - relative scale alone can cause these apparent polarity...
Certain focal points of this gravitation/cosmological constant (which isn't found to be constant BTW) would cause the conversion of energy back into matter, by the same basic means that complex matter is recycled into radiative force, e.g. light energy. This process would appear as the inverse of energy's apparent outward motion, i.e external force would be focused into an inward conservation of energy, creating the particles of matter, in the same fashion that gravity causes the accretion of star and planetary matter from the gaseous, et al., components of material debris.
Now in regard to what lies beyond this universe, there is not really anything in one sense, and everything in another. That is to say: this universe, as it appears, is a universe of polarities, contrasts, relativity etc., but this is not fundamental. These variations are in fact ultimately dependent upon the existence of the invariant reality, undefined, unlimited, immutable Existence, for even the notion of this engendered universe to be rational, and explainable. If it were not for this illimitable, and unengendered reality this universe could have no discernible reason, but instead existence itself would be a self contradicting non-sense, utterly incomprehensible, not explainable by science in any meaningful way. Since it is rational, the undefinable absolute is a certain originating first Principle.
This is a cause for much debate, but there is a certain origin, definably unknowable, and completely grand origin, whether this be limited to evolutionary, or or implicitly all-encompassing, which is what's most argued. This can be summed by whether potential ideal completeness is essential, or non-essential. Because we realize this potential, it is clearly essential, or it could never even be guessed at. Stimulus-response, or more accurately primitive, cause and effect, in all degrees of complexity, would be the highest truth, and no comprehension of its own rational nature could exist otherwise. (again this is widely debated, my position, fully conscious of all the opposition's presented arguments, is stated as is)
The universe is essential, ever-existing, and eternal, with all manner of appearing rational effects, including apparent variation of its stature, composition, and cumulative energy, which are all derivatives of the essence of reality, or the core primitive/principle which is absolute, and not rational, or definable.
God bless.