noun
Big Bang theory
Refers specifically to the cosmological model of the universe's origin.
ビッグバン宇宙論は、宇宙が約138億年前に誕生したと説明する。
The Big Bang theory explains that the universe was born about 13.8 billion years ago.
From English 'Big Bang' + 宇宙論 (uchūron, 'cosmology').