cosmos - everything that exists anywhere; "they study the evolution of the universe"; "the biggest tree in existence"extragalactic nebula, galaxy - (astronomy) a collection of star systems; any of the billions of systems each having many stars and nebulae and dust; "`extragalactic nebula' is a former name for `galaxy'" closed universe - (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 amounts of dark matter natural order - the physical universe considered as an orderly system subject to natural (not human or supernatural) laws nature - the natural physical world including plants and animals and landscapes etc.; "they tried to preserve nature as they found it" |