(cosmology) a universe in which there is sufficient matter to halt the expansion that began with the big bang and to cause the universe to collapse again; the visible matter is only 10 percent of the matter required for closure but there may be large amou
(cosmology) a universe that is spatially closed and in which there is sufficient matter to halt the expansion that began with the big bang; the visible matter is only 10 percent of the matter required for closure but there may be large amounts of dark matter