noun
expanding universe
Scientific term used in cosmology to describe the expansion of the universe.
膨張宇宙の理論は、ビッグバン宇宙論の基礎です。
The theory of the expanding universe is the foundation of Big Bang cosmology.
宇宙膨張 is a more common word order for 'cosmic expansion', while 膨張宇宙 emphasizes the universe itself as expanding.
Compound of 膨張 (expansion) and 宇宙 (universe).